Well, I figure since making "build-up" threads are the thing to do I might as well start one on my own 4.9 turbo build. Don't expect this project to finish too soon though....lol Here's a little history behind the project. Everytime I look at my Iroc-Z I say "man, that thing is too damn heavy in the front". I wanted to build a car that was everything my Iroc-Z wasn't but still keep some of that wicked power. What I wanted was to build a small, light, stick-shift, mid-engined sports car...which led me straight to the Fiero which I had always liked (and considered buying when I originally bought the Camaro). I had also been getting into turbochargers and forced induction in general. I used N20 with great results on the Camaro, such great results that I will never build a completely N/A car again! This plus the fact that Blow-off valves sound so sweet paved the way for a turbo Fiero. The project was originally going to be a 3.1 turbo. The plan was to use the 3.1 block with dished aluminum pistons and the Fiero iron heads to get a low enough compression for lots of boost, enough to make descent power out of the 3.1. As it turns out though the compression ratio was going to be 7.2:1, and although it could be done it would not work as well as I had expected. I could have bought forged pistons and all that jazz but money is an issue and I didn't want to spend alot on this project. This is when I came to the budget Fiero builder's favorite, the 4.9 PFI Cadillac motor. When inquireing into the sawp I had planned on using a turbo and asked if anyone had done this or knew if there was room, and that was when I stumbled upon PBJ's turbo 4.9 swap in the early stages. My mind was then set. It could be done and will be done. I set up a budget of $4,000 and not a penny more for this projects total (including the car, a paint job, and tools). So now the $4,000 4.9 Turbo project has begun, and I'll post all the updates right here.
Here's the car....a diamond in the rough. This is a 90,XXX mile 1986 Fiero SE 2m4. You can see I have a little fiberglassing and bondo work to do before the paint job, but the interior is really nice and the car actually runs. Not bad for only $700!
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07:12 PM
FieroGTT Member
Posts: 489 From: Hard Hittin' New Britain, CT Registered: Oct 2002
Ok, straight to the turbo. PBJ is using a GM4 unit with great success, he almost perfectly sized the turbo for his application. Since I am going to use an intercooler I needed a slightly smaller turbo to generate more boost (to account for the pressure drop across the intercooler). This is what I came up with. This is a Holset H2 turbo. In Garret equivalents It's close to a T4 or a big T3/T4 hybrid with a 1.00 turbine A/R wheel. Some Sy/Ty guys have used this kind of a turbo on their modded 4.3, which should be pretty close to a stock 4.9. The compressor map I read put me in a pretty good efficiency range but the turbo might prove to be a tad smaller than hoped for, but it will still work pretty well.
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07:42 PM
PBJ Member
Posts: 4167 From: London, On., Canada Registered: Jan 2001
Ummm.....no. I mean it can be done... and it would probably be cool... but its just not what I want.
The turbo is going to be cool. I've been doing a little research on import tuning, where a supercharger seems to make more sense. I dont think you are going to need any more low end on the 4.9 (reason for a SC), so the turbo really rounds out the power curve.
I'm in the process of doing a N/A 4.9L now. cant wait to see how your work progresses. Good luck, and keep us posted. -john
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11:24 AM
crzyone Member
Posts: 3571 From: Alberta, Canada Registered: Dec 2000
I'm throwing a 100 shot on my 4.9, for those occasional times I might find a faster car. Document your swap and keep track of materials and you may get some business selling turbo 4.9 kits
------------------ 4.9 in progress!
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02:01 PM
Apr 4th, 2003
FieroGTT Member
Posts: 489 From: Hard Hittin' New Britain, CT Registered: Oct 2002
Here is the intercooler and BOV I have decided to use. The intercooler is a Saab 900 unit with aluminum end tanks. It has a great efficiency for its size due to its "double thick" design. I've seen it used on Fiero's before with great success, almost looks custom made for the application. The BOV is a stock 1G DSM unit which is good to about 1 bar or a bit over. Since I won't be running close to 1 bar of boost this will work great for me. Once again this is a proven custom turbo item, (and I like the sound too ).
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11:10 PM
FieroGTT Member
Posts: 489 From: Hard Hittin' New Britain, CT Registered: Oct 2002
Here are some more of the swaps details. After much debate I have decided to use the 5-spd Isuzu transmission. I know alot of people don't like the Isuzu, but let's face it, the Getrag is not that much stronger. The Isuzu has higher gearing which will be a huge plus for me and this setup. Also it is cheaper to replace when it does get blown. So Isuzu it is. I have also decided on the SPEC stage 3 clutch, after calling many companies and heaing many testimonials. The SPEC clutch had the best customer service and customer satisfaction at the right prices. Special thanks to Jncomutt for pointing me in that direction. So I guess this will be the once and for all test of the clutch. Guys wanna place bets? No I won't be using slicks (I'm not THAT hell bent on breaking my drivetrain). Also keep in mind that balls out speed and 1/4 mile times are NOT what this car is being built for. If it was I would be using an automatic transmission. This is being built more for driving fun which is really what the Fiero is designed for in the first place. I had plenty of drag racing in the Camaro which is really setup more for that purpose than the Fiero.
[This message has been edited by FieroGTT (edited 04-04-2003).]
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11:18 PM
Apr 5th, 2003
Dennis LaGrua Member
Posts: 15145 From: Hillsborough, NJ U.S.A. Registered: May 2000
A turbo 4.9L in a Fiero should be a real performer. However, I am interested in seeing the level of reliability that this engine can provide while being boosted. I'm not saying that a turbocharged aluminum block 4.9L engine won't be reliable; it's just that having this setup is like crusing in unchartered waters. After these engines are run for a few passes at the drags, that should tell the story.
Here is the intercooler and BOV I have decided to use. The intercooler is a Saab 900 unit with aluminum end tanks. It has a great efficiency for its size due to its "double thick" design. I've seen it used on Fiero's before with great success, almost looks custom made for the application. The BOV is a stock 1G DSM ...
I see youve decided on the Isuzu, also with the spec clutch, good choice. They say the tranny is weak, but the problem is not really with the case and design, but with how it handles the 'shock' in the diff.
I'd highly reccomend you do yourself a favor and invest in a phantom grip LSD. It'll only set you back a few hundred bucks in comparison to the time and money you will save having to replace your tranny. Plus it'll help out on those track times when the boost kicks in
As always, GOOD LUCK! I'm using a similar intercooler, btw, but mine is from an RX7 I believe.
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03:08 AM
BV MotorSports Member
Posts: 4821 From: Oak Hill, WV Registered: May 2001
Here is the intercooler and BOV I have decided to use. The intercooler is a Saab 900 unit with aluminum end tanks. It has a great efficiency for its size due to its "double thick" design. I've seen it used on Fiero's before with great success, almost looks custom made for the application. The BOV is a stock 1G DSM unit which is good to about 1 bar or a bit over. Since I won't be running close to 1 bar of boost this will work great for me. Once again this is a proven custom turbo item, (and I like the sound too ).
I have used the 1g DSM bypass valve on many turbo cars I have built over the years. Works really well. I doesnt like to be used as a BOV though on engines with over 12psi of boost. I had to crush the top hump of it in a vice for 14psi or higher or it would bleed off boost. Should be fine for you if you dont go boost happy
Steven
------------------ 88 Fiero coupe 2.5 5 speed, Custom IHI RHB6 turbo equipped, gutted and track abused 88 Coupe Project "F-88" has begun....Classified TOP SECRET **your gonna love this** 88 Fiero Coupe 2.5/auto Not sure what I am going to do to this one! 87 Fiero GT 14.9/ 89mph **4.9 PFI swap in progress** 87 Fiero Coupe 91k miles 86 Fiero SE 88 Mazda RX-7 'vert SBC v8 383/T-5 Always have engines, fiero parts and accessories for sale. Custom engine swaps and chassis modifications are available.
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04:08 AM
FieroGTT Member
Posts: 489 From: Hard Hittin' New Britain, CT Registered: Oct 2002
I don't think this car will see much track time if at all. Closet track is like 2 hours away and I want to stay away from a lot of drag racing to spare the drive train. It will see alot of G-tech runs and Pike time though, Jncomutt know what I mean
The mastermind behind everything will be the GM "749" ECM, the same one used in Sy/Ty's and turbo Sunbirds. I'm a firm believer that a boosted motor will be just as reliable as the same motor N/A as long as detonation is under control. Good tuning is the key.
I have used the 1g DSM bypass valve on many turbo cars I have built over the years. Works really well. I doesnt like to be used as a BOV though on engines with over 12psi of boost. I had to crush the top hump of it in a vice for 14psi or higher or it would bleed off boost. Should be fine for you if you dont go boost happy
Steven
You must have had a bad BOV, 1G DSM BOVs should be good to at least 19-20PSI some work to 22PSI. Yeah you crush them to run boost over 20 PSI usually. My 1G valve and thousands of others have passed leakdown tests over 18-19 PSI.
FieroGTT, Nice clutch! I love mine, it is however a little rough starting in 1st gear. Good luck!
Jim 87 GT T-TOP V8 87 GT parts car 95 Talon TSi AWD w/20g, GM MAFT, all supporting mods except FMIC
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12:00 PM
PFF
System Bot
Dennis LaGrua Member
Posts: 15145 From: Hillsborough, NJ U.S.A. Registered: May 2000
I don't think this car will see much track time if at all. Closet track is like 2 hours away and I want to stay away from a lot of drag racing to spare the drive train. It will see alot of G-tech runs and Pike time though, Jncomutt know what I mean
The mastermind behind everything will be the GM "749" ECM, the same one used in Sy/Ty's and turbo Sunbirds. I'm a firm believer that a boosted motor will be just as reliable as the same motor N/A as long as detonation is under control. Good tuning is the key.
I like your choice of ECM. It's well documented for boosted engines but as you know a new throttle body with an IAC will need to be adapted. I agree that good tuning is really key to optimizing power and engine longevity in a turbocharged engine. Reliability could also be affected by boost levels used. When I expressed my concerns about reliability it was only because I've never seen an engine of this type boosted. Floating steel sleeve cylinders, an aluminum block and an engine designed for a 4500 RPM redline could make for some very interesting results. Everything may work out perfectly but having few turbo 4.9L combos like this in the Fiero world;I'm sure that there will be many eager to see the result. What ET's are you shooting for?
Yes I have already spoken to PBJ on the subject and will be using a TBI throttle body with the injectors removed to get the IAC. The only concern I had with the motor was the floating sleeves, however, with the low boost I am using (well under 1 bar, 1/2 bar at most) I don't think the dynamic compression will reach dangerously high levels as to compromise the motor. but I guess PBJ and myself will find out the truth first hand soon enough. The 4,500RPM redline is due to the restrictions in the heads. It can rev higher. I feel the aluminum block to be an advantage rather than a hinderance. Too bad the heads aren't aluminum.
I am aware of the dangers of over revving a motor, especially the 4.9. I have purposely chosen a turbo that will make power BEFORE 5,500RPMS so that high revving won't be needed for power.
As far as ET's... I know its always a taboo.... but with some good tuning and traction I expect this to break 12's. However, whether this car will ever see traction or not is another story.
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10:53 PM
Jul 10th, 2003
PBJ Member
Posts: 4167 From: London, On., Canada Registered: Jan 2001
