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Advice on camshaft for turbo 3800 build by crashmydaytona
Started on: 04-05-2015 08:29 PM
Replies: 47 (1361 views)
Last post by: nocuttt on 05-22-2015 03:36 AM
crashmydaytona
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Report this Post04-05-2015 08:29 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
What is the largets cam (not sure if that is correct terminology or not) I can use with stock heads? I was thinking of putting in an st4 cam but not sure if head work is required or not. my thoughts were to put in a cam, bigger springs, and a double roller since i have the engine apart. I think the st5 is to much cam for me just watching vids of them. At the same time i think the st1 is not enough. If you have a recommendation on a cam let me know all the parts needed with it springs, retainers, push rods and so on thanks.
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Report this Post04-06-2015 10:36 AM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
A ST1 will give better throttle response and make boost at a lower rpm. I wouldn't, personally, put anything larger than a ST2 into a 3.8L.

If your planning on a 76+mm turbo and spinning to 7000rpm or more and making 600+ rwhp, then a bigger cam might help. Only other reason for a cam that big is if your looking for the sound at idle.

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

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crashmydaytona
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Report this Post04-06-2015 05:06 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks I will go with the stattama ST1 cam, PAC 130# springs, rollmaster double timing chain. Is there any other parts I need to replace running this cam? I have never put a cam in so not sure what valve train parts I need to order to have everything on hand. Thanks for helping.
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Report this Post04-06-2015 05:12 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
I agree with LFiero67. I'll go further and say your money would be better spent in a good cylinder head porting job and buying a good turbo and intercooler and keep the cam selection conservative. You can make very good power with a decent turbo and intercooler while using a relatively small cam.

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LFiero67
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Report this Post04-06-2015 05:34 PM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
Need retainers to match the springs, 3800 retainers will reduce installed height, which increases spring pressure and reduces seal clearance. I'd suggest modified steel retainers from ZZP when you order the cam. New locks would't hurt either. I put new lifters in mine as well, but not a necessity. If you do change lifters, the replacements now are "LS7" style. They will work with stock pushrods, but do increase preload. I measured for correct preload and ordered pushrods to match. If your engine is a lower mileage unit, I'd probably just leave them alone.


What turbo are you looking at?

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

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crashmydaytona
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Report this Post04-06-2015 07:14 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
Darth can the average local machine shop port heads? This is the reason i want to leave them stock I dont want to spend the money
on zzp heads and i am not sure if local guys no what to do.

Lfiero67 my original turbo selection is a diesel turbo off a late 90's GM pickup but i am now open to suggestions. Assuming an st1 cam, 130 spings double roller and possibly some head work what turbo or turbos would you guys recommend?
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Report this Post04-06-2015 07:34 PM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
I wouldn't bother porting the heads, unless your going all out build, it's not worth the money. I wouldn't take the heads off the engine if possible. Hard to get a better head gasket seal than factory. The Zzp CNC heads are a decent deal if they are still 1000. By the time you pay someone to port the heads, valve job, guides, seals etc, it ends up being pretty close to that anyway.

Turbo totally depends on goals. 58-62mm compressor in a new style billet wheel are capable of breaking transmissions all day long. Not familiar with the 6.5 diesel turbos, could try it and see how it performs. I would put money into something like a 5858 for up to 450 WHP or a 6262/6266 for 450-600 whp before I would spend money on the heads.

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

[This message has been edited by LFiero67 (edited 04-06-2015).]

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crashmydaytona
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Report this Post04-06-2015 08:19 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
Unfortunately the heads are already off do to mice. Here are the specs on the turbo.
Brand: Borgwarner / IHI
Model: 51T-32
Size: T3/T04E
Compressor A/R: 0.7
Compressor trim: 46
Turbine A/R: 0.6
Turbine trim: stage II
Flange type: standard t3

Is 6262/6266 sizes? If so what brands would you recommend? the brands I know are Garrett, Borg Warner, Holset and chinese.
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Report this Post04-06-2015 08:33 PM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
Those are sizes in Precision Turbo terms. Both are 62mm inducer compressor, with either a 62 or 66mm turbine exducer. Can be purchased in a wide range of turbine housings from t3, t4, buick style, syclone etc. I run a t3 0.63 to achieve maximum throttle response,and a low boost threshold, but have a transmission that cost more than the car did. I was looking to be able to make boost easily while staging the car at the track, I can make 18+ lbs of boost with the car sitting still. A t4 will spool slightly later and slower which could be easier on the transmission and may or may not make slightly more power in higher rpm. The new turbines flow so well that housings are less of an issue than older style turbos as far as top end performance. Ported "S" compressor cover will reduce part throttle surge, which can happen with a turbo that moves a lot of air at lower rpms.

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

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crashmydaytona
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Report this Post04-06-2015 09:10 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
if I go precision 6262 how should i order it I already have a t3 flange welded to the manifold so t3. I will be using stock 4t60 or 4t65hd transmission. the car will be used mostly around town and very occasionally hit the drag strip. I see there are a couple different options when ordering thanks for helping i appreciate it.
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Report this Post04-06-2015 09:25 PM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
T3 0.63 will give quickest boost response, 0.83 will be slightly slower. I would go with v-band outlet housing, get a 3" vband flange and clamp to build your exhaust on, makes removal and installation easy and generally leak free. Buy a t3 turbine blanket to wrap around housing, helps keep the heat inside.

Should make around 400whp on 10psi with what you have listed in this thread. Trans life will vary.

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

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crashmydaytona
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Report this Post04-06-2015 09:32 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks thats just what i needed someone to spell it out for me. This stuff can be confusing for a newbie. Now to start the search for the best price.
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Report this Post04-06-2015 09:41 PM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
If you can find it anywhere for under 1099 shipped, that's a good deal. I purchased in 2011, when they were 899 at a few places, tough to find anyone under precisions MSRP now.

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

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crashmydaytona
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Report this Post04-07-2015 11:03 AM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
If I have the turbine housing ceramic coated will I still need the turbine blanket? Will ceramic even hold up to the temperatures turbos produce?
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Report this Post04-07-2015 11:17 AM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
Blanket ensures no burns if you or something touches it. Coating holds heat in, but still gets hot on outside. Turbine housing can get glowing hot, so only the 2000 degree or so rated coating will last if you go that way.

I've run the DEI titanium blanket and wrapped my muffler with the wrap in 2011, it's still all soft. I would recommend that over the cheaper DEI or other brands that require the silicone spray. They dry out and flake apart, and are very itchy lol.

DEI 010141 would be the kit I used for T3 turbine, $180 from summit, not sure how that compares to coating.

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

[This message has been edited by LFiero67 (edited 04-07-2015).]

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Report this Post04-07-2015 05:57 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by crashmydaytona:

Darth can the average local machine shop port heads? This is the reason i want to leave them stock I dont want to spend the money
on zzp heads and i am not sure if local guys no what to do.



I wouldn't trust just any shop or anyone to port heads unless they know what they are doing. It is very easy to make a port flow worse than stock if material is removed from the wrong location. I learned to port heads in college where we used a flow bench to test results of removing material in different places in the ports. What I learned there was removing even a little bit of material from the right areas of the ports can result in significant gains in airflow. We also learned that just simply opening the ports up (removing a lot of material) did not always produce gains. There are some excellent books on the subject if you want to learn to do it yourself. It isn't difficult, but it isn't for everyone either.

On the other hand if you do have a budget and don't want to attempt to port the heads yourself, it may be wise to spend the money on other mods rather than head porting. It really just depends on what you ultimately want out of this engine and how long you want it to last.

[This message has been edited by Darth Fiero (edited 04-07-2015).]

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Report this Post04-07-2015 10:14 PM Click Here to See the Profile for mr_coreanSend a Private Message to mr_coreanEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by LFiero67:

I run a t3 0.63 to achieve maximum throttle response,and a low boost threshold, but have a transmission that cost more than the car did. I was looking to be able to make boost easily while staging the car at the track, I can make 18+ lbs of boost with the car sitting still.



How much boost are you making at the top end with that setup? This is a great thread for noobs like me btw, thanks for the conversation gents!

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crashmydaytona
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Report this Post04-07-2015 11:35 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Darth Fiero:


I wouldn't trust just any shop or anyone to port heads unless they know what they are doing. It is very easy to make a port flow worse than stock if material is removed from the wrong location. I learned to port heads in college where we used a flow bench to test results of removing material in different places in the ports. What I learned there was removing even a little bit of material from the right areas of the ports can result in significant gains in airflow. We also learned that just simply opening the ports up (removing a lot of material) did not always produce gains. There are some excellent books on the subject if you want to learn to do it yourself. It isn't difficult, but it isn't for everyone either.

On the other hand if you do have a budget and don't want to attempt to port the heads yourself, it may be wise to spend the money on other mods rather than head porting. It really just depends on what you ultimately want out of this engine and how long you want it to last.



That would be a great skill to have. What tools are used to port? I would guess without a flow bench learning would be difficult.
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Report this Post04-07-2015 11:43 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by LFiero67:

Blanket ensures no burns if you or something touches it. Coating holds heat in, but still gets hot on outside. Turbine housing can get glowing hot, so only the 2000 degree or so rated coating will last if you go that way.

I've run the DEI titanium blanket and wrapped my muffler with the wrap in 2011, it's still all soft. I would recommend that over the cheaper DEI or other brands that require the silicone spray. They dry out and flake apart, and are very itchy lol.

DEI 010141 would be the kit I used for T3 turbine, $180 from summit, not sure how that compares to coating.


The ceramic coating is an extra $100 sounds like the kit will be money better spent. This turbo stuff is really expensive. Is there parts that you can go cheap on? Such as blow off valves, waste gates, etc.
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Report this Post04-07-2015 11:58 PM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
10.2 @ 134 was on 18-19 lbs boost. Have run up to 23-24 lbs on the street, but not yet on the track.


I wouldn't cheap out on wastegate, but knock off BOV is ok. Wastegate failure can take out an engine in a hurry. Bov, some guys don't even run one.

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

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Report this Post04-08-2015 10:36 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by crashmydaytona:


That would be a great skill to have. What tools are used to port?


You need a die grinder (electric is better than pneumatic for this kind of task unless you have a really good compressor).

You need some carbide bits in various shapes (usually Christmas trees and footballs) that are suitable for grinding on cast iron. These will be used for removing the bulk of material. Follow up with a sand paper roll to knock off all the sharp edges.

You need hearing and eye protection. I also like to connect a wet-vac to the opposite end of the port I'm working on and have it going while I'm porting to keep the port clear of metal shavings - makes it easier to see what you are doing.

[This message has been edited by Darth Fiero (edited 04-08-2015).]

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Report this Post04-08-2015 11:10 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Darth Fiero:


You need a die grinder (electric is better than pneumatic for this kind of task unless you have a really good compressor).

You need some carbide bits in various shapes (usually Christmas trees and footballs) that are suitable for grinding on cast iron. These will be used for removing the bulk of material. Follow up with a sand paper roll to knock off all the sharp edges.

You need hearing and eye protection. I also like to connect a wet-vac to the opposite end of the port I'm working on and have it going while I'm porting to keep the port clear of metal shavings - makes it easier to see what you are doing.



Tools are simple already have them. I am going to see if i can find a flow bench in town I can use. Do you have any before and after pics of heads you have done? This could be a fun side project.
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Report this Post04-08-2015 11:22 PM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have some for the 3800. I've got a thread going on duke heads right now, same basic idea.

Around here it's about $15 a port for flow bench tests. Before and after is about the best you're gonna get, noone is gonna let you sit at it

I would get David Vizards book on porting. Ryan is right when he says you need to know what you're doing. You could trash your heads

[This message has been edited by Slammed (edited 04-08-2015).]

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Report this Post04-08-2015 11:55 PM Click Here to See the Profile for IanT720Click Here to Email IanT720Send a Private Message to IanT720Edit/Delete MessageReply w/QuoteDirect Link to This Post
Just to add... I have a ST3 in my 3800, it's otherwise stock besides 130lb springs and a double roller. I'm using a Precision 6776 turbo. 67mm with a .68 AR on the exhaust side. Can't tell you how good it runs since it's not yet . But that's my setup, I wanted low boost but high flow, plus it will be a semi daily driver, so instant boost isn't nessecary. Infact with the big cam and big turbo it should be a great cruiser with the stock gears. Not all high strung. But when you put your foot down.... Guess I gotta find out!

------------------
1987 Fiero GTX 3800 Turbo... My Build, ST3 Cam, Lowered, Wheels, and pics enjoy!http://www.fiero.nl/forum/Forum1/HTML/089483.html

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Report this Post04-09-2015 10:49 AM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
There is nothing "high strung" about a smaller setup.

I've done the big cam, ported heads, every mod under the sun thing with the m90 blower. Had XPZ cam, 2.6-2.8" pulley, ported blower, intercooler, port matched intake, fully ported heads, headers, full 3" exhaust with high flow muffler, you name it, I had it or had tried it. I can 100% say the turbo setup I have now is way nicer to daily drive than my blower setup was. Idle is smooth, lots of vacuum for brakes, cruises at a low rpm easily, never has blower surge, exhaust is barely noticeable until you get on it. it's just a all around nicer car. Yet makes far more power and can run over 1second quicker in the 1/4 mile, with a small cam, stock heads, stock intake with just a hv3 insert. The car will not make boost unless I want it to, but when I want it, it's there. Can change it from a mid 11 second to low 10 second car, while driving with the flick of a switch and turn of a knob. I would describe my big cam setup as far more high strung than the turbo setup any day.

The bigger the cam, the higher the power band is pushed, requiring more stall to allow the engine to perform. Problem is, the higher the converter stall is, the less likely it is to couple at higher hp. The custom Niel Chance and ZZP 3250 stall and converters I used originally with the turbo setup would slip over 20% at top end and near 40% at bottom of shifts. My 10.2 pass was about 21% slip through the traps. I've spent the last few years trying to get a transmission and converter combo that will last and couple efficiently. The trans I have sorted, hopefully the new converter in the garage will work also. The ST1 I have shifting at 6400 rpm, bigger cam would need more rpm, putting more wear and tear on engine and drive train. M90 setup was shifting around 6700-6800 rpm I hated spinning the stock components that high, but it needed it to stay in the power band.

You could run steeper gears, to increase the rpm and make the bigger cam more useable, however with the 4t60/4t65 the drive chain setup gets more likely to stretch with every increase in gearing. I had the 3.29 7/8 chain originally, against the suggestion of Dave at Triple Edge Performance, it lasted 1month. Listened to Dave this time and went with 2.93 gears, managed to last a summer, but still a yearly replacement item until I got the GMR 1" chain. Manual transmissions obviously won't have these issues.

Guys can run whatever they want, but I've seen a lot of people on Grand Prix forums suggest huge cams to guys looking for 400-450 whp, and it just doesn't make sense. It sacrifices drivability, narrows the power band, shifts it higher in rpm, makes it harder on parts, but why when the power can be made without those issues.

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

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Report this Post04-09-2015 10:50 AM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post

LFiero67

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Sorry for the novel lol.
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Report this Post04-09-2015 01:53 PM Click Here to See the Profile for nosracSend a Private Message to nosracEdit/Delete MessageReply w/QuoteDirect Link to This Post
ST1 cam + recommended assessories
Stock Heads.
BorgWarner EFR 7064 Turbo with internal gate T4 (NO need for Waste Gate or BOV)

Plog +
Rear mounted turbo with custom flange mated to stock rear manifold

http://www.ebay.com/itm/84-...em20c61e3c63&vxp=mtr
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Report this Post04-09-2015 03:57 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by nosrac:

ST1 cam + recommended assessories
Stock Heads.
BorgWarner EFR 7064 Turbo with internal gate T4 (NO need for Waste Gate or BOV)

Plog +
Rear mounted turbo with custom flange mated to stock rear manifold

http://www.ebay.com/itm/84-...em20c61e3c63&vxp=mtr


That's one pricy turbo!
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mr_corean
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Report this Post04-11-2015 09:29 PM Click Here to See the Profile for mr_coreanSend a Private Message to mr_coreanEdit/Delete MessageReply w/QuoteDirect Link to This Post
So the general consensus I'm seeing here on the cams for the car is that the ST1 is plenty of cam and the other two are overkill or for sound. Also the stock cam has a separation of 112* and that by increasing that slightly can help a turbo motor a bit by not allowing boost to just be pushed straight through the cylinder when the valves open. Looking at the specs of the ST1 cam and I see that it has 112* lobe separation like the stock cam does. This brings me to the question of how much if any advantage does the ST1 have over a stock cam? I'm having a hell of a time finding the actual specs for a stock cam other than it has 112* lobe separation. I'm currently piecing together a build that I want to be very fast and very reliable while being easy to drive. The idea is to do it with very large boost number. If having an ST1 cam in that setup won't do anything significant over the stock cam then would I even need to go there? Not trying to hijack the thread, crash, but it seems we have similar goals and the information could potentially help us both save a few hundred bones.
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1fast2m4
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Report this Post04-12-2015 10:42 AM Click Here to See the Profile for 1fast2m4Send a Private Message to 1fast2m4Edit/Delete MessageReply w/QuoteDirect Link to This Post
Not to Hijack but........

When I assembled my engine last month I was using the totally stock 4t65e-hd that came with my L67 so I figured the trans would be my biggest limiting factor so I didn't worry about squeaking every ounce of power out of the engine and just did the 90lb valve springs and left the cam and timing chain alone. But now in a few hours I'll be headed towards Pittsburgh to pick up a Built trans & stall converter that's been a proven in our application.

Now that I'm dropping the cradle again to swap out the tranny, with only #90 valve springs do I have any suitable cam options? I was really thinking about the Yella Terra 1.9 roller rockers and calling it done. what do you guys think?

------------------
1986 SE 3800SC/4t65eHD (12.871@104.96)
HX-40, FrozenBoost I/C, 80lb injectors & E85 Coming soon.....

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crashmydaytona
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Report this Post04-12-2015 02:46 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by mr_corean:

So the general consensus I'm seeing here on the cams for the car is that the ST1 is plenty of cam and the other two are overkill or for sound. Also the stock cam has a separation of 112* and that by increasing that slightly can help a turbo motor a bit by not allowing boost to just be pushed straight through the cylinder when the valves open. Looking at the specs of the ST1 cam and I see that it has 112* lobe separation like the stock cam does. This brings me to the question of how much if any advantage does the ST1 have over a stock cam? I'm having a hell of a time finding the actual specs for a stock cam other than it has 112* lobe separation. I'm currently piecing together a build that I want to be very fast and very reliable while being easy to drive. The idea is to do it with very large boost number. If having an ST1 cam in that setup won't do anything significant over the stock cam then would I even need to go there? Not trying to hijack the thread, crash, but it seems we have similar goals and the information could potentially help us both save a few hundred bones.


Hijack away. Good question. It would be nice to know what gains the st1 cam gives over stock. I can't find the answer online so i will call zzp when i get a chance and find out.
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crashmydaytona
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Report this Post04-12-2015 02:57 PM Click Here to See the Profile for crashmydaytonaSend a Private Message to crashmydaytonaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 1fast2m4:

Not to Hijack but........

When I assembled my engine last month I was using the totally stock 4t65e-hd that came with my L67 so I figured the trans would be my biggest limiting factor so I didn't worry about squeaking every ounce of power out of the engine and just did the 90lb valve springs and left the cam and timing chain alone. But now in a few hours I'll be headed towards Pittsburgh to pick up a Built trans & stall converter that's been a proven in our application.

Now that I'm dropping the cradle again to swap out the tranny, with only #90 valve springs do I have any suitable cam options? I was really thinking about the Yella Terra 1.9 roller rockers and calling it done. what do you guys think?



I'm no expert obviously but have been reading a lot of threads on the subject and most would say that rockers are not the way to go on a turbo setup. The gains from rockers are very limited compared to even a very mild cam on turbo setups. Not sure why rockers give good gains on supercharged motors but not turbos. Just what i have read.

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mr_corean
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Report this Post04-12-2015 09:48 PM Click Here to See the Profile for mr_coreanSend a Private Message to mr_coreanEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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Originally posted by crashmydaytona:


I'm no expert obviously but have been reading a lot of threads on the subject and most would say that rockers are not the way to go on a turbo setup. The gains from rockers are very limited compared to even a very mild cam on turbo setups. Not sure why rockers give good gains on supercharged motors but not turbos. Just what i have read.


This is a good point I had forgotten about. I'm interested to hear the answer on this one too.
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Darth Fiero
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Report this Post04-13-2015 10:19 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by crashmydaytona:


I'm no expert obviously but have been reading a lot of threads on the subject and most would say that rockers are not the way to go on a turbo setup. The gains from rockers are very limited compared to even a very mild cam on turbo setups. Not sure why rockers give good gains on supercharged motors but not turbos. Just what i have read.


I have a set of 1.84 ratio roller rockers on my 3800 Series 2 Turbo. I can tell you that the addition of these rockers did increase performance of the engine (most noticeably above 4000 rpm) vs. the stock rockers.

However, these aftermarket rockers did have some flaws I had to correct.

The rockers I am using are made by Yellow Terra and the alignment on some of the valves was not correct when I first installed them. I had to modify the pedestals that came with the rocker kit to correct this alignment issue. This isn't an issue that applies only to turbo builds as it is a mechanical/design problem with the rocker kit. If you install a set of these rockers and don't check and correct the alignment issues, the result can be premature wear and even failure of certain valvetrain parts.

I have been told the modified GM factory rocker arms which are also sold for these engines by various vendors don't suffer from this problem.
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LFiero67
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Report this Post04-13-2015 10:33 PM Click Here to See the Profile for LFiero67Click Here to Email LFiero67Send a Private Message to LFiero67Edit/Delete MessageReply w/QuoteDirect Link to This Post
I think Justin's car showed that rockers work well on turbo setups too. A turbo specific cam that creates more turbo friendly valve events will obviously be better, but the stock l67/l36 camshaft has no overlap already, which is one of the goals of a turbo cam anyway.

------------------
10.263 @ 134.44MPH - 1.49 60'
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 130lb springs, comp pushrods, HV3, ARP Rod bolts, otherwise stock L36.


Old M90 XP Cam time -
11.425 @115.60
1.543 60'

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1fast2m4
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Report this Post04-14-2015 03:15 PM Click Here to See the Profile for 1fast2m4Send a Private Message to 1fast2m4Edit/Delete MessageReply w/QuoteDirect Link to This Post
Right or wrong I just pulled the trigger on the Yella Tera 1.9's I just couldn't make myself pull the cam and swap out springs. and it just felt wrong dropping the engine again to do the trans exchange yet do noting.

Datrh Fiero: what was the issue with your rockers? alignment of the roller tip on the valve? what was the cure?

------------------
1986 SE 3800SC/4t65eHD (12.871@104.96)
HX-40, FrozenBoost I/C, 80lb injectors & E85 Coming soon.....

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mitchjl22
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Report this Post04-15-2015 12:34 PM Click Here to See the Profile for mitchjl22Click Here to Email mitchjl22Send a Private Message to mitchjl22Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by nosrac:

ST1 cam + recommended assessories
Stock Heads.
BorgWarner EFR 7064 Turbo with internal gate T4 (NO need for Waste Gate or BOV)

Plog +
Rear mounted turbo with custom flange mated to stock rear manifold

http://www.ebay.com/itm/84-...em20c61e3c63&vxp=mtr


Would you be able to run this turbo without cam and stock heads? I was thinking...... I have a plog already.

-Mitch
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Darth Fiero
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Report this Post04-15-2015 03:11 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 1fast2m4:

Datrh Fiero: what was the issue with your rockers? alignment of the roller tip on the valve? what was the cure?



Yes, the problem was alignment of the roller tip with the valve.

To correct it, I had to modify the pedestals where they install into the supplied base plate (which aligns them). This required some grinding of the base of the pedestal where it inserts into the base plate (to allow the pedestal to be turned slightly, allowing me to align the rocker's tip correctly onto the valve) and staking the base of the pedestal using a chisel (to tighten up / lock the pedestal into the new position).

A dremel with a fiberglass cut-off wheel worked great for this; and this process can be done with most of the rockers installed on the engine (just remove and modify the pedestals beneath the rockers that are out of alignment and leave the other ones alone).
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nosrac
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Report this Post04-15-2015 04:27 PM Click Here to See the Profile for nosracSend a Private Message to nosracEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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Originally posted by mitchjl22:


Would you be able to run this turbo without cam and stock heads? I was thinking...... I have a plog already.

-Mitch


Sure, NO problems there.
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