Hey guys:
i really don't get how to pick the right a/r ratio for the turbo for my fiero. its an 88 formula with a bored and stroked 2.8. which makes it approximently 3.2l or 190cid. from what I've read I need either a .63 or a .84 a/r. I am getting a garret t3 super 60 because my calculations show i can make 10psi by 2500 rpm with this turbo. that is as long as have the right a/r. PLEASE HELP ME!

For my turbo project, i'm also putting a t3 super 60 (AR .63) on my 3.1 engine. A .63 would probably be perfect for ya too....not as much turbo lag from a .84... The project should be starting very shortly

-Coop

That turbo is too small. It will produce a ton of intake heat. I would go bigger.

T3 is really small for a 3.2L block... you would do better w/ a TD06 or a T67... you might have a little more lag but not much...

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'86 Fiero GT

www.KylesFiero.tk www.XoticRydz.tk

too small? hmmmm.... I was looking at a t3/t4, but it seemed like there would be more lag to make the same amount of boost. i was going to get a t3/t4 with a t04E 60 trim compressor housing. would that be a better plan?

actually you can do that since my friend CT26 in his MR2 Turbo will make full boost at 3k when its set to 10psi and thats a 2L engine... hes getting ready to put on a Garrett turbo thats like a T03/T04 and it will spool at around 4500 rpm making 15-18 psi... so you might get away will that small of a turbo if you dont rev the crap out of it... if you really want exact numbers tehen you need to go to www.turbocalculator.com and buy that software...

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'86 Fiero GT

www.KylesFiero.tk www.XoticRydz.tk

well i correct myself. after looking at it again i think that to make 10psi by 2500 rpm i might want to go with a t3/t4 with a t04e-40 compressor side and a t3 .63 exhaust side. wow. i'm losing it. how does that sound to you guys?

The A/R ratio is the air/radius ratio. The R is a measurement of the wheels (from the center shaft to the discharge area (average) in both the exhaust or compressor ports. As such it is simply a measurement of turbocharger size. Rather than get into an academic study of turbocharger theory, here is my recommendation. For a 2.8L use a .63 compressor A/R and .48 A/R exhaust for a Garrett T-3 size turbo. That should give you 10 psi without any problems. I've tried it an it works!.
For the 3.4L you can have the .84 A/R compressor wheel from the Buick Grand National installed in a T-3 compressor housing. There are three size wheels that will fit. .48, .63, and .84. . Stay away from a T3/T4 hybrid unless you know exactly what you are doing . Make an error here and you'll be waiting years for the turbo to spool up. All kidding aside it is better to err on the side of too small a turbo than than too large a turbo. I have supplied a chip to a guy in upsate NY who used a Garrret w a 57 trim compressor and his reports lead me to believe that it's too large. When you are building an engine for serious street competition, fast spool up will help you win those races.

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87GT 3.4 Turbo Best 0-60 5.2 seconds
http://www.turbochargerpower.com/turbo.htm

quote Originally posted by v6fiero: Hey guys: i really don't get how to pick the right a/r ratio for the turbo for my fiero. its an 88 formula with a bored and stroked 2.8. which makes it approximently 3.2l or 190cid. from what I've read I need either a .63 or a .84 a/r. I am getting a garret t3 super 60 because my calculations show i can make 10psi by 2500 rpm with this turbo. that is as long as have the right a/r. PLEASE HELP ME!

I believe we had this conversation before.

If you can give me an accurate measurement of what the peak torque is coming out of that motor, then I can figure out your Volumetric Efficiency, and figure out what turbo you need.

Computer dyno, G-tech pro, I don't care, something that can tell me the torque coming out of the motor.

*edit: What redline are you aiming for? This is the equation figure out the airflow:

Displacement (190ci) -X- RPM (???) -X- Targeted boost pressure (.6895 Bar) -X- Volumetric Effeciency (???) = your airflow in CFM

Then you need the pressure ratio:

14.7 + Target psi, then divide that by 14.7.

14.7+10/14.7=a pressure ratio of 1.68

Now that you have the Airflow and the Pressure Ratio. Compare the two, and you look at where it comes out on the compressor map. You want to get on the "Fantasy Island," which is where the turbo will acheive peak effeciency.

Here's an example. This is the map for my turbo, compared with what my motor puts out, and the calculations I made resulted in this.

Let me know the info I need. Peak torque, and desired redline.
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Petty Officer Michael C Casaceli
Patrol Squadron Ten, United States Navy
1988 Pontiac Fiero 2.5L, soon to be 2.2L ECOTEC TURBO (THE PROJECT HAS STARTED!!!)
1988 Oldsmobile Firenza 2.0L non-turbo (R.I.P.my beloved J-body. K.I.A. by a Ford)
1994 Chevy S-10 4.3, it's finally here, and it is gorgeous!

[This message has been edited by fieroturbo (edited 07-21-2004).]

yeah, i know fieroturbo. i have a dyno appointment next week

SWEEET!!!!

(any chance of a video of it? )

t3/o4E with a 60 trim wheel is a pretty good matchup for a 3.2 It will make 10 psi by 3500 rpm. Thats not lag at all and will flow a ton more air then a t3. Any t3 turbo is too small. get rid of it. Lag is overrated anyways.

a .48 exh housing on a t3 is way too small. You will choke your motor after 5k rpm. Will produce a lot of heat and hp will drop big time. Go with a .63 on a t3/4

The fiero already launches well down low. 0-30 times are in the 2.3 second range on a stock car. You add a 3.2 and a turbo and you are around 2 seconds. Thats impressive even if you dont' have a small turbo with quick spool. A t3/4 will build boost before 3500 and make 10 psi by that rpm. SO you will have boost down low but not all of it. I say big deal. 5 psi at 2500 rpm is better then none and the larger turbo will give you more top end instead of falling on its face like a t3 will.

Fiero owners like using t3 turbos cause they are so cheap to acquire even though they aren't properly sized. Backyard installers here. Be different. do it right

yea, you people don't realize that this is a T3 SUPER 60 he is talking about. Not a normal T3 with small AR. The super 60 has enough size to spool up quickly with a 3.1+ engine but also not so small that it will die out quickly. A .63 would be a great size for ya...nothing more than a .83, and don't even bother with a t4, that's just getting ridiculous

-Coop

A super 60 is still too small. its been plotted on a chart. Its way off too the even at 8 psi and this is on a 2.8!

But whatever, dont' beleive me. I am trying to help you. Go with a t3 and you will not like it. its just too small. They were put on 1.8-2.3 liter engines for a reason!

The Garrett T-3 series of turbos have been proven on a number of applications to deliver well over 300 HP.
Just a few comments:
. There is a guy that I burned a chip for in NY that runs a T-3 w a 57 trim wheel on his 2.8L and he is reporting rather slow turbo spool up.
The McClaren turbocharger setup on the Turbo Grand Prix 3.1L used a Garrett T-3 with a compressor A/R of .83. Those engines scream.
While I am not going to flame anyone for suggesting the T-4 size, I believe that the T-3 size is sufficient and will do the job. Remember a large turbo kills the bottom end. For a street/strip car that's where you want the power.

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87GT 3.4 Turbo Best 0-60 5.2 seconds
http://www.turbochargerpower.com/turbo.htm

if its a strip car your only in the bottom end once and the rest of the time you are up in the boost... so to make up for the lack of boost AND to help spool the turbo he could use a small shot of n20 for the bottom end he needs... i think thats what were doing w/ the new turbo going on the mr2turbo. ahh, i can just feel 300rwhp in that car now....

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'86 Fiero GT

www.KylesFiero.tk www.XoticRydz.tk

Well, i am looking to have a street strip car that will make 350hp+

There might be a video possibility, we'll see

[This message has been edited by v6fiero (edited 07-22-2004).]

Don't waste your money on a T3 for that size of engine. I built a T3/T61 for a 1.6lt SOHC civic and he got full boost by 4000rpm (with 1/2 the displacement). This car ran an 11.3@119 in the 1/4. The L36 (3.8 liter) kits I've built for both g-body and f-body cars uses a different T3/T4 and starts building boost at a little over 2k with full boost before 3k. The L36 grand prix went from 160hp to 325/369 non-intecooled and the f-body went from 165ish (don't remember the exact number to 349/415 despite the speed limiter not allowing us go over 4300rpm. Both engines have ZERO computer tuning and are internally stock. I have the f-body dyno sheet in front of me and we were over 200hp at 3000rpm.

I don't think you will have a spool problem with the hybrid and you will have a much larger compressor allowing you to support future upgrades better. I build and sell them and don't mind giving anyone on the board a good price on one (starting at around 375).

quote Originally posted by Dennis LaGrua: The Garrett T-3 series of turbos have been proven on a number of applications to deliver well over 300 HP. Just a few comments: . There is a guy that I burned a chip for in NY that runs a T-3 w a 57 trim wheel on his 2.8L and he is reporting rather slow turbo spool up. The McClaren turbocharger setup on the Turbo Grand Prix 3.1L used a Garrett T-3 with a compressor A/R of .83. Those engines scream. While I am not going to flame anyone for suggesting the T-4 size, I believe that the T-3 size is sufficient and will do the job. Remember a large turbo kills the bottom end. For a street/strip car that's where you want the power.

Technically the TGPs turbo is a T25, is it not? And stock, it's no screamer, the internals are actually the same as the NA version of the 3.1 (cam, pistons, etc). There is one sittin' in a junkyard down here, and there is a ten foot pole people are using to navigate their way around it.

I recently put a Garrett T3 on my 2.8 Compressor A/R .60 and exhaust A/R .48. I can report that there is very little if any turbo lag and will deliver 10psi of boost from 2500 to 6500rpm. The intake does get warm. I'm not intercooled yet but I am planning for one over the winter. Bottom line is it works and works well.

Steve

quote Originally posted by spearce: I recently put a Garrett T3 on my 2.8 Compressor A/R .60 and exhaust A/R .48. I can report that there is very little if any turbo lag and will deliver 10psi of boost from 2500 to 6500rpm. The intake does get warm. I'm not intercooled yet but I am planning for one over the winter. Bottom line is it works and works well. Steve

Exactly what i was looking for. some one who has done it on a fiero with a 2.8-3.2 any others?
Dennis what do you think for a 3.2?

quote Originally posted by spearce: I recently put a Garrett T3 on my 2.8 Compressor A/R .60 and exhaust A/R .48. I can report that there is very little if any turbo lag and will deliver 10psi of boost from 2500 to 6500rpm. The intake does get warm. I'm not intercooled yet but I am planning for one over the winter. Bottom line is it works and works well. Steve

I would love to see your turbo outlet charge temps with that small of a turbo. I say 300 degrees+ I think stating your intake gets warm is an understatement. Yea your turbo might work but a better sized turbo will work even better.

Its not about boost, its about cfm

In corky bells book he even mentions that a small turbo will produce no lag but the charge temps int he upper rpm range non intercooled will be atrocious! I would rather sacrifice a bit of lag for more cfm and lower intake charge temps esp in a nonintercooled application. But whatever. Its your engine run it on the ragged edge with too small of a turbo if you want, thats your choice. I am done helping in this thread. It seems you already have your mind made up cause you can prob get a t3 for next to nothing. Its the Fiero owners way. Why I even bother to try and help is beyond me.

I will say it again. T3 turbos were put on 1.8-2.3 liter engines from the factory for a reason.

Punisher, I agree that a better sized turbo would work better but spending $1000.00 plus CDN for a turbo wasn't an option. The only time that the intake gets hot is when I'm at the drag strip. The car seldom sees much boost when cruising. When the pocketbook can take it a new turbo will be purchased.

Steve

Sorry, since there are some many experts in here about turbos, I have a question:

I'm trying to turbo-charge my new engine, 3.4 DOHC and I'm aiming for 7-8 PSI Intercooler, and I'm trying to size the right turbo for the job!

The engine size is 207 ci
The red line is 7000 rpms
The car has 5 speed getrac
And the compression has being lower to flat 9.0 The stock one is (9.71)
I don't know the CFM for the motor, but I'm sure somebody could get it. Or guesstimate it?
The Torque will pic between 4300-4500 rpms

And I want to full spool by 3300 rpms, and no power drop until 6800 rpms at least!

I have being looking at a GT-32 with a .78 ar.

What do you guys think?

ok first off all there are tons of self proclaimed experts on this forum. Before you all go out and spend a ton of money on a turbo, plug your numbers into this http://www.turbofast.com.au/turbomap.html and see what you can come up with. Put all your engine specs in (calculate 85% for 2 valve/cyl engines and 90% for 4 valve engines) and start clicking next map. When you get one that puts your optimum setup down the peak of the island, you have found a suitable map. If it runs off the left side of the map across the dotted line, stay away. Thats the compressor surge zone and its too large. If the dots are out on the right side of the island, the turbo is too small.

As for turbine A/R, a .48-.63 will be fine for a 2.8-3.4L engine. I run a .70 A/R t3 turbine on my 3.8L and it lags. I could of ran a .63 on mine and got away with it. I just bought a 4000 stall so the lag will be decreased when its all back together.

Peace!

quote Originally posted by The Punisher: I would love to see your turbo outlet charge temps with that small of a turbo. I say 300 degrees+ I think stating your intake gets warm is an understatement. Yea your turbo might work but a better sized turbo will work even better. Its not about boost, its about cfm In corky bells book he even mentions that a small turbo will produce no lag but the charge temps int he upper rpm range non intercooled will be atrocious! I would rather sacrifice a bit of lag for more cfm and lower intake charge temps esp in a nonintercooled application. But whatever. Its your engine run it on the ragged edge with too small of a turbo if you want, thats your choice. I am done helping in this thread. It seems you already have your mind made up cause you can prob get a t3 for next to nothing. Its the Fiero owners way. Why I even bother to try and help is beyond me. I will say it again. T3 turbos were put on 1.8-2.3 liter engines from the factory for a reason.

it's not like i have my mind set or anything. I'm jsut looking for people who have actually done it.... sorry....

Few questions, is the car an auto or stick? if it is an auto what stall is the converter? If you have a
loose converter (2200-3000 stall) then you can run a bigger exhaust housing and come out the whole pretty good, if it is less depends on the stall, you will start making boost after the car reaches like 20mph+. If the car were a stick I would stay with a smaller A/R for bottom end spool up unless you want slip the clutch like crazy. Combo is everything. For example when I went from a stock turbo setup on a GN with .63A/R exhaust housing to a .81 A/R 4 bolt exhaust housing P trim, the car didn't make any boost until about 15-20mph with 2000-stall converter. I switched to an Art Carr 9" 3300-3500 stall converter, I was able to launch with 10 psi off the line. I would run the small housing on the street, it is more fun but the bigger the exhaust housing will give you better top end power. If you worried about back pressure being too much on a smaller A/R run an external waste gate before the turbo on the cross over pipe on the header, that would eliminate most of that.

just my $.02

HTH

Prasad

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"Turbo Cars are like hot women. A little edgy, every guy wants one, some guys can't handle them, and if you throw a little alchohol in the mix they'll rock your world"
1986 GT (waiting for Buick GN setup trasplant)
1984SE 5 Speed W/SBC V8
1987 Buick GN(10.70@124MPH)
1987 Trans Am SBC 355cid Twin Turbo(no track times yet)
1992 GMC Typhoon(13.20@ 99mph)
Other cars; JaguarXJ6 & Mercedes AMG 500SEC

quote Originally posted by v6fiero: so i looked at the turbo calcutlator thing - will some one make sure that i am doing this right. I used the following information Point 1 6000rpm(redline) 10psi VE=85 CE=75 Point 2 2500rpm(max boost) 10psi VE=85 CE=75 Point 3 1250rpm(boost start) 1psi VE=85 CE=75 Bore=3.55 Stroke=3.31 Num of Cyl=6 Air Temp=25 Inter Eff=60 (its a fiero) According to what they say that means that i need a t62-1???? I thought that I needed to be in the middle island, but they say near the surge limit! which is right!?

62-1 is a T4 derived turbocharger built around a 62-1 compressor wheel. I'd highly recommend doing the math for yourself once you get a few turbos that look good. Turbocalc is a good quick and dirty tool but there is a TON of varience in it's results. The math isn't that hard to do if you just do it and map out your own compressor wheel. BTW, there is ALOT more to turbo design than compressor maps. Lots of things will put boost into an engine but to make it perfect, you have to take the time to work the numbers.

I don't know how many self proclaimed turbo experts there are on the board but with over a dozen turbo kits and hundreds of turbochargers spec to application all over the world, I've been down this road more than once. Take my advise and do the math for yourself.

I have done the math my self. but thats what led me to the t3 super 60.

CFM=CID/1728 x RPM/2 x VE

But i only have two questions: RPM is where i want to be at full boost right? and Whats the VE on a Fiero. I substituted 1...

If so CFM=190//1728 x 2500/2 x 1

CFM= .11 x 1250 x 1

CFM=137.5

PR= 14.7xboost pressure/14.7

PR=14.7+10/14.7
PR=1.68

CFM Boosted = CFM unboosted x PR

CFM Boosted = 137.5 x 1.68

CFM Boosted = 231

Lb/min = cfm boosted x .07
lb/min = 231 x .07
lb/min = 16.17

????s any one
thoughts...

as for the car:
Its a 5 speed getrag with a Spec Stage 3 clutch

[This message has been edited by v6fiero (edited 07-23-2004).]

quote Originally posted by v6fiero: and Whats the VE on a Fiero. I substituted 1...

If I remember correctly, the VE of the stock V6 peaks around 85% at about 3600 rpm.

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Doug Chase
Chase Race
Custom roll cage and exhaust fabrication

ok cool. I'll recalculate then