There are two aspects to the low end torque on the HF V6 engines. The VVT is part of it, but it's also the dual-mode intake. Also, the LY7 is 10.2:1 CR, not 11.5:1. I probably wouldn't go 11.5:1 on a 3.4 DOHC.
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08:24 PM
Feb 6th, 2011
bnevets27 Member
Posts: 264 From: Ontario, Canada Registered: Oct 2007
the tranny i have found that works with this engine are from a Cadillac CTS 6 spd standard for $650 on car parts .com so for about $1300 you can get engine and tranny
the tranny i have found that works with this engine are from a Cadillac CTS 6 spd standard for $650 on car parts .com so for about $1300 you can get engine and tranny
It's not a transaxle, what are you going to do with it in a Fiero.
well I think i will go back to the old school way bigger is better so I will be selling the 5 spd Getrag with low mile and the stock 2.8 with low miles
Originally posted by ghost187x: dumb question: can any of these engines produce power @ 9000 rpm like the s2000 f20c ?
Anything will produce power at 9000 rpm if you build it to. Just a matter of how much time and $$$ you want to put into doing so. And it's only useful if you're building an oval track or formula car.
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09:31 AM
Apr 5th, 2011
Xyster Member
Posts: 1444 From: Great Falls MT Registered: Apr 2011
After reading this thread I had to create an account just to get the info out. The LLT (in transverse config) uses the same bellhousing as many other GM engines. This bellhousing is the same as the Fiero's. This link is for the 6T75 mated to the LLT in the Acadia, Enclave and Traverse.
GM has actually used a very small number of bellhousing over the years, especially when compared to the broad variety of engines that have been offered.
Originally posted by Xyster: After reading this thread I had to create an account just to get the info out. The LLT (in transverse config) uses the same bellhousing as many other GM engines. This bellhousing is the same as the Fiero's. This link is for the 6T75 mated to the LLT in the Acadia, Enclave and Traverse.
GM has actually used a very small number of bellhousing over the years, especially when compared to the broad variety of engines that have been offered.
I hope this clarifies some of the confusion.
All of the High Feature engines (http://en.wikipedia.org/wik..._High_Feature_engine) use the High Feature bolt pattern for the bell housing. It is NOT the same as the Fiero which uses the GM metric pattern. The Wikipedia page on GM bellhousing patterns lists the longitudinal configuration High Feature engines as having the Metric pattern, but this is false. The picture you linked to is I believe just a generic picture of the 6t75, probably the version which was mated to the 3.9/3.5 High Value engines, which do use the Metric pattern, and are in several other GM cars.
And the only transverse configuration of High Feature engine in a USDM vehicle with a manual trans that I can find, is the Saab 9-3 2.8t, but they are extremely hard to find. It may be possible that some of the other foreign market cars such as the Opel Vectra may have manual transmission pairings with the High Feature V6, but the only info I've been able to find which seems to be a definite HF V6 with manual trans option other than the Saab 2.8t, is the Alfa Romeo 159/Spider/Brera. These Alfas also have a 6 speed Magneti Marelli Selespeed option, which could be interesting for anyone looking to have paddle shift with a real gearbox.
EDIT: After poking around a little more, it appears the Selespeed was only on the 2.2 Alfas, and not the 3.2 HF V6 cars, unfortunately. But with an adapter plate and a little engineering, any interested party could probably get one of the Selespeeds working with another engine in a Fiero.
[This message has been edited by dobey (edited 04-10-2011).]
ya the tranny is the big thing i have found a few 9 3 Tanny's but like you said hard to find so they do want more for them I really feel that a well thought out 3.4 DOHC would make as much power it just would be 90 pounds more . the 3.4 had like 215 at the crank and the best LY7 has 275 but it has more compression and a better intake . I know that Micheal Smith took a 3.4 DOHC from 170 whp to 240 whp with just cam timing and home made intake but the intake killed low end i am thinking Individual Throttle bodies and the compression you could get about 300 at the crank and i think with the ITB you wont have the low end torque loss . i would like to try it to just see
Originally posted by engine man: ya the tranny is the big thing i have found a few 9 3 Tanny's but like you said hard to find so they do want more for them I really feel that a well thought out 3.4 DOHC would make as much power it just would be 90 pounds more . the 3.4 had like 215 at the crank and the best LY7 has 275 but it has more compression and a better intake . I know that Micheal Smith took a 3.4 DOHC from 170 whp to 240 whp with just cam timing and home made intake but the intake killed low end i am thinking Individual Throttle bodies and the compression you could get about 300 at the crank and i think with the ITB you wont have the low end torque loss . i would like to try it to just see
The LY7 apparently has a few different intakes, depending on which platform the engine is in. And the dual-stage intake on the LY7 isn't really designed with purely power in mind. It is pretty big and odd, which doesn't make for a great intake for making lots of power, no. The LLT intake is much better, and I imagine the intake on the new DOHC for the 2012 V6 Camaros will be even better. Lots more info in this thread I found:
The guy's heads in that thread were ported/polished to flow 327/203 cfm at 0.500 lift for intake/exhaust respectively. Those are some pretty good numbers, and I think the LY7 heads have the same casting.
the stock flow numbers for the 3.4 DOHC lift I E .05 52 52 .10 101 100 .15 150 138 .20 190 164 .25 220 184 .30 246 196 .35 266 203 .40 278 210 as you can see the 3.4dohc heads flow as well as the new LLT engine on intake and better on exhaust . LLT flow # "Intake .200 188 .300 255 .400 275 .450 281 .500 284
Originally posted by engine man: it just would be 90 pounds more .
Thats just a crack whore in your trunk... no reason to be concerned about that...
quote
Originally posted by engine man:I know that Micheal Smith took a 3.4 DOHC from 170 whp to 240 whp with just cam timing and home made intake but the intake killed low end
Don't forget the custom equal length long tube headers.
The LLT is a better engine. It's lighter, better packaged and can make that power stock, with stock driveability.
yes the LLT has better drivablity part of it is due to the DI & VVT and the rest is due to the dual intake + 11.5 to 1 compression and its not cairing that crack whore with that said the 3.4 dohc could make the same power due to its heads flow as well but it would lack some of the low end torque due to non VVT but a intake with dual runners could be made and i have a idea for that but not sure if it is a good idea or bad . pistons can be made for the 3.4 to any compression you want but the big thing is the 3.4 dohc has many transmission that fit it and ECU to work with the swap but I am sure that in time the 3.6 will be put in a fiero and it will be great
these are 96 & 97 heads the ones your looking at are 91-95 96 & 97 had better heads this is where i got my numbers from but the seems to be some discrepancies on what they are http://60degreev6.com/forum...p/46962-Flow-numbers
[This message has been edited by engine man (edited 04-11-2011).]
these are 96 & 97 heads the ones your looking at are 91-95 96 & 97 had better heads this is where i got my numbers from but the seems to be some discrepancies on what they are http://60degreev6.com/forum...p/46962-Flow-numbers
That post says they are for 91-95, and that is a huge difference. And even if they were the 96-97, I doubt the flow would be *that* much of an improvement over the 91-95 heads, in stock form. If those numbers aren't just flat BS from somewhere else, they are probably for ported heads, and not stock, would be my guess.
yes i think so to those # i got nust be ported or just BS . well in a feww weeks i will have the money to buy a LY7 the real ? is do i start down that road
yes i think so to those # i got nust be ported or just BS . well in a feww weeks i will have the money to buy a LY7 the real ? is do i start down that road
Well if it's going to be like the rest of your supposed projects, I guess you can take solace in the fact that you'll never finish it.
Originally posted by MadDanceSkillz: That engine also makes like 25hp or close to it at 2,000rpm. The Fiero 2.5l that produces about 75whp makes 30hp or so at 2,000rpm.
There's a link to a dyno for one. It's pathetic...
I can't wait until HFV6's start showing up in Fieros...
I'm not so sure about that. That dyno chart you linked says that engine is making about 40hp at 2000 rpm…
And about 110 lb-ft of torque at 2000 rpm; which is about what the 2.5 Duke makes stock, ever.
They're not bad engines, but the kids with S2000s tend to beat the utter crap out of them. They apparently don't know they're allowed to shift past 3rd gear, and don't have to shift at 8000 RPM every time.
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06:25 PM
Doug85GT Member
Posts: 9482 From: Sacramento CA USA Registered: May 2003
I did more research and found that my formula is all wrong. The correct formula is completely different. Larry Meaux's formula can be found here and other places on the web:
For the LQ1 the formula is Peak_HP = Flow_CFM * .257 * Number_of_Cylinders
263.5 * .257 * 6 = 406 hp theoretical max
For the LLT the formula is Peak_HP = Flow_CFM * .285 * Number_of_Cylinders
275 * .285 * 6 = 470 hp theoretical max
The LLT uses the .285 factor because of the following:
quote
.257 Factor = for beginning engine builders and engines near 10.0:1 Comp Ratio
.285 Factor = would be for Professional engine builders with wet sump pans, lightweight rotating assemblies, low tension great sealing rings, deep oil pans, etc. and excellent use of inertia/wave tuning with 9.5 to 11.5:1 Comp Ratios or 11.5 to 13.0:1 CR ranges without fully utilizing inertia/wave tuning effects
.300 to .310 Factor = Current ProStock Technology with dry sump, unlimited carburetion, High Comp Ratio, ultra lightweight rotating assembly, etc, and maximum use of inertia/wave tuning, etc, 14:1 to 17:1 Comp Ratios.
(usually no better than .3200 efficiency or no worse than .2980 eff %)
[This message has been edited by Doug85GT (edited 04-21-2011).]
well acording to this site http://www.bgsoflex.com/flowcalc1.html the engines will need to ht over 10,000 rpm to make that max hp at that point those 6 bolt mains are needed with just a few xtra race parts but thats just a race engine at that point but it's cool i think just think off the sound that would make at that rpm yehaa
[This message has been edited by engine man (edited 04-21-2011).]
I did some research and it seems the LY7 & LLT are having timing chain stretch issues i think GM did a recall can anyone confirm this recall
There does seem to be a recall which changes the OLM calibration in the ECM. Apparently it's because people take too long between oil changes, and perhaps drive them harder than they should be, in the cars they're in, causing extraneous wear on the chains. And people using dino oil instead of synthetic blends.
Hmm not sure how to take that info is this due to keeping it at higher revs because the engine needs the lower gear when pulling a suv or there just trying to say it wears out due to lack of oil change
I think probably more related to oil life perhaps. Not entirely sure though as it's hard to find any real concrete information. And nobody wants to admit that they weren't maintaining the car properly, because then it would be their fault.
But what's interesting is that I can't seem to find the same complaints about the Saab 2.8t engines. I haven't actually found a single timing chain failure thread, even specifically looking for them. But the Caddy/Chevy/Pontiac forums with the LY7/LLT engines seem a bit more ablaze with them.
I think I might go with a Saab 2.8 for my swap, with some appropriate modifications. I wish I could find appropriate info for all the different High Feature heads, cams, intakes, and internal specs. If the rods are the same length in the 2.8 and new LFX, and have the same journal sizes, I might look at using the LFX rods in the 2.8. It's hard to find the right info though. The LP9 at least seems to be the only one with a decent looking upper intake, without having the cover on, though, which is nice.
I would love to do this swap but i know that i cant afford to due to i would need some one to do all the ecu pcm and we still don't know if the whole wiring harness plus gages need to go in yet so i will just be driving the stock 2.8 for this summer and making it look good but will keep a eye open for that person who puts one in first
