For those of you who have done LT1/LS1 swaps into your Fieros, which transmissions did you use and what was the degree of difficulty in using them or any major problems you ran into and what you had to do to overcome?

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1985 Pontiac Fiero 2M4

As far as transmission is concerned, the LT1 is similar to a regular SBC, and can use Archie's adapter plate. The LS1 is entirely different and requires a different adapter plate. LS1Swap is the only person I know of who's successfully completed an LS1 swap. You can get a kit from Archie to do an LT1 swap, you just have to move the engine/tranny slightly to the left to clear the OptiSpark and water pump on the front of the engine.

Can you use any other transmissions with the LT1 besides the Fiero ones and the Buick 4T60 3-spd auto?

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1985 Pontiac Fiero 2M4

4T60 nomenclature:

4: Four forward "gears"
T: Transverse mounted
60: How "beefy" the tranny is. The 40 is weaker and the 80 is stronger.

quote Originally posted by Formula88: You can get a kit from Archie to do an LT1 swap, you just have to move the engine/tranny slightly to the left to clear the OptiSpark and water pump on the front of the engine.

Don't let the words "slightly to the left" mis-lead you into thinking that this is easy to do. Right now, I'm working the trial fit of my LT-1/Getrag into the engine bay so I speak from experience. This conversion is certainly doable, many on this forum have, but it is not for novices. Not to imply you are a novice, just trying to caution you.

Anyhow, on an LT-1 conversion using Archie's kit, not only do you have to weld 3 new engine/tranny brackets to the cradle, but you also have to cut about 6" +- from both frame side rails to get everything to fit into the engine bay. You also have to cut a window in the wheel well so the water pump can be installed, which is done after the engine and cradle are in place.

Bottom line is if you are a novice, don't have metal working and/or welding capability, stay with the conventional SBC conversion. If I had to do it over again, I would go this route instead.

If you still want to go the LT-1 route, PM me and I'll send photos of the cuts that will need to be done.

Good luck.

Karl

quote Originally posted by tejas: If you still want to go the LT-1 route, PM me and I'll send photos of the cuts that will need to be done. Good luck. Karl

Actually, as my name suggests, I am going the LT5 route. Been extensively sourcing an LT5 crate motor, but probably won't start on the project until next fall or winter.

I was just wondering how involved an LT1/LS1 swap is, since they would be the closest motors near to what the LT5 is.

Did you know the ZR-1 Corvette topped out at 196 MPH and still got 30 MPG on the highway? Imagine that in the much lighter Fiero... at least MPG wise.

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1985 Pontiac Fiero 2M4

quote Originally posted by tejas: Don't let the words "slightly to the left" mis-lead you into thinking that this is easy to do. Right now, I'm working the trial fit of my LT-1/Getrag into the engine bay so I speak from experience. This conversion is certainly doable, many on this forum have, but it is not for novices. Not to imply you are a novice, just trying to caution you.

Good advice. Yeah, I said you had to move the engine. I didn't say what you had to do to do that. It does require notching the frame and getting custom axles. V8Archie's website has more info on what's required.

quote Originally posted by Formula88: The LS1 had a different bolt pattern than previous SBC engines.

No, it doesn't. It uses a different flywheel/clutch form factor, but the trans bolt pattern is the same.

quote Originally posted by LT-5Fiero: Actually, as my name suggests, I am going the LT5 route. Been extensively sourcing an LT5 crate motor, but probably won't start on the project until next fall or winter. I was just wondering how involved an LT1/LS1 swap is, since they would be the closest motors near to what the LT5 is. Did you know the ZR-1 Corvette topped out at 196 MPH and still got 30 MPG on the highway? Imagine that in the much lighter Fiero... at least MPG wise.

Of course thats with a 6 speed tranny too and different rear gearing. My C4 auto gets 19.6 around town, 27-28 on the road. Be nice if my new V8 Fiero got just 1/2 of that.

I honestly don't know that much about an LT5 I do know that it is a 32 valve DOHC engine. Typically these engine have giant heads I think you should get a cross measurement of these if I could. You will notice in the pic I am sending the heads go straight up from the block this leaves room for the exhaust manifolds. the 32 valve engine may not. I am not saying it won't fit ( I don't know) I am just saying this is something I would look into. It will be an impressive swap if you can get it to fit, but I think it will be a tight one. I would bet that it does have to be moved to the left just like the LT1 swaps. The ls1 doesn't by the way. My trans stayed in its stock position. I think the LT1 crowd could help you more than I. Actually as far as technically advanced the lt5 exceeds an LS1. The ls1 has allot of little tweaks over a SBC, but gains most of its advantages over a typical SBC by the angle of the valves, the head design in general, the ability of aluminum to wick away heat, and the ability to custom tune the computer any way you like. but t it is still a single cam pushrod engine. the LT5 is not. It probably shares more in common with a northstar. I hope it can be done it would be one heck of an engine in a Fiero.
You are both kind of right about the bolt pattern the LS1 has every bolt as the typical SBC except one, but it also has an additional two in the pan,. Which is more or less just another part of the block. You can even see a spot for the hole that is missing. The reason they didn't use it is because it lines up exactly with a head bolt

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LS1 in and running :)

http://ls1swap.tripod.com/

I am proud of you for attempting the swap with a lt5. I figure if in the 80's they had a way to fit a big block in there sideways then the lt5 should work also. I would try but college dosen't dictate funding for such a swap but that would be the ultimate swap if u ask me. Check the measurements of one of those against a big block and see if they are close to the same.

LS1Swap, what transmission and transaxles did you use in your swap? I was considering the 4T80E out of a Deville/Seville. I can get a remanufactured one through my job for about $1,900, but I will probably have to source the transaxles else where.

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1985 Pontiac Fiero 2M4

The N*'s a TIGHT fit and it's physically smaller than the size I'm guessing the LT5 is.

quote Originally posted by Will: The N*'s a TIGHT fit and it's physically smaller than the size I'm guessing the LT5 is.

I'm willing to lose the trunk if need be, I don't see any real use of it for me.

Is it possible to alter the firewall for the engine to fit, like you can do on front-engine cars?

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1985 Pontiac Fiero 2M4
Soon to become the LT-5 powered Pontiac Fiero ZR

I used the original getrag five speed that was in the car. I did switch from a type 3 CV joint (stock) to a type 1. In hind sight this wasn't an absolute necessity but it did make it easier for me.

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LS1 in and running :)

http://ls1swap.tripod.com/

quote Originally posted by LS1swap: I used the original getrag five speed that was in the car. I did switch from a type 3 CV joint (stock) to a type 1. In hind sight this wasn't an absolute necessity but it did make it easier for me.

What's the difference? What'sa type 2?

It has a longer barrel and the end of the splined shaft is flat instead of tapered. There is a flange that sticks out of the LS1 Block. The clamp hits it on a type I but the longer barrel of a type I places the clamp past it. The flat end also allows the clip to be mounted on the end easily, which moves the entire tripot joint out about 1/4" which is just enough to allow a 168 tooth flywheel to clear the tripot. I know not much of this seems to make much sense but it was one of the keys in getting my swap to work. It doesn't matter unless someone wants to use a 168 tooth flywheel.

The top tripot joint in the pic is a type III the bottom one is a type I. I don't know about a type II ????

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LS1 in and running :)

http://ls1swap.tripod.com/

my N* has *1/4th of an inch* of clearance to the rear trunk/chassis-menber. (if you get rid of this, be prepared to weld in a tubular replacement. It's the entire rear of the Fiero's chassis nearly!)

LT-5 could be made to fit I think, but trunk will have to go, and you may need to both notch the passanger compartment/firewall a bit (it can be done, sure, you may loose recline room.) and/or lay the engine back 5 or 10 degrees or so.

Either option should be fine. (I'd go dry sump in any event, so laying back motor won't be a big deal at all.)

I'm more concerned with legenth! Will the LT-5 fit in legenth?! My guess is yes, but it's gonna be tight, and you will have to relocate some elements (most likely; oil filter for one.)

Good luck to you sir! The LT-5 is one HELL of a motor, probally the best GM has ever produced. It's 405hp output was way under what it was capable of, I know several 6-700hp n/a ZR-1 owners....

I'd use the Getrag, it has a good record with 400hp SBCs, the 405hp LT-5 should do fine with it. QM clutch would be der-requir here.

Talk to V8Archie.

Best!
Ben.

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Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

I have no doubt a SPEC stage III would hold up to an LT5, and as much work as this project is gonna be the last thing I'd wanna deal with is QM's costly and complex setup. But it's irrelevant since LT5Fiero said he wants to do an automatic. (egads!!)

I don't think the trunk is what you'll have to worry about so much, though. You'll need to worry about the right side strut tower and, to a lesser extent, the decklid. The wiring is going to be a nightmare too, but it would be so cool to have a Fiero with a "Power Key". ZR-1 fanatics know what I'm talking about.

Anything is possible with enough money and ingenuity, and this one is going to take a lot of both. Five years ago LT5 crate engines were going for $26k apiece. If anything I bet they're more than that now, if they are available at all. It's rare even to find them used, since most ZR-1s are mothballed as collectibles now. You could put a Lingenfelter LS1 in for less than that. <moment of silence for speaking the name>

There are just much easier and less-expensive ways to get as much power from other engines, as demonstrated here by a few V6 and V8 owners who have taken it to those levels. The uniqueness factor must be higher on the priority list in this case.

Dave

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- Electron Blue '88 GT 5-speed (1 of 1): Before After ZZ430 Ram-Port FI--Wanna Race? Follow it here on the Forum!
- Silver '88 GT 5-speed (1 of 139) w/cammed 3.4
- '98 6-speed Corvette Coupe, '87 Coupe SOLD!

quote Originally posted by crazyd: But it's irrelevant since LT5Fiero said he wants to do an automatic. (egads!!) The wiring is going to be a nightmare too, but it would be so cool to have a Fiero with a "Power Key". ZR-1 fanatics know what I'm talking about. Anything is possible with enough money and ingenuity, and this one is going to take a lot of both. Five years ago LT5 crate engines were going for $26k apiece. If anything I bet they're more than that now, if they are available at all. It's rare even to find them used, since most ZR-1s are mothballed as collectibles now. You could put a Lingenfelter LS1 in for less than that. <moment of silence for speaking the name> There are just much easier and less-expensive ways to get as much power from other engines, as demonstrated here by a few V6 and V8 owners who have taken it to those levels. The uniqueness factor must be higher on the priority list in this case. Dave

There are a few reasons I originally picked the 4T80E:

1) I've grown up on an automatic, the Ford C6 3-spd, strongest auto tranny Ford every produced, practically a bullet proof housing.

2) I had heard of the Getrag only supporting up to 350 ft-lbs with serious care. When I'm through with it, it will be getting well over 425 ft-lbs.

If the Getrag will work, then I will use it. I was really looking for a 6-spd if at all possible. The thought of a 200 MPH Fiero is constantly dancing in my head , but then I remind myself I don't need a 6-spd to achieve that, the well-geared 4-spd/5-spd trannies in the GT40 took it to well above 200.

Explain this Power Key. I've never heard of it, and I've only recently had the fascination for the LT-5.

Crate motors on Ebay still go for about $14,000, but I can find some good motors from a junkers for between $7,000-$12,000. I'm basically going to tear down the engine and rebuild it from the ground up, so even a junker engine should be fine as long as there is no block damage.

Uniqueness, sheer power, the potential, and just the plain awesomeness of the look of the LT-5. Ever seen an LT-5 with all 16 of those intake runners chrome polished? I'm sorry, but it puts the LS1/LS6's looks to shame

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1985 Pontiac Fiero 2M4
Soon to become the LT-5 powered Pontiac Fiero ZR

quote Originally posted by LT-5Fiero: I was really looking for a 6-spd if at all possible.

Aren't we all. This looks like the best possibility right now: http://www.eiptuning.com/transmissions/transmissions.html

(scroll to bottom)

quote Explain this Power Key. I've never heard of it, and I've only recently had the fascination for the LT-5.

Bascially, the ZR1 has a "Valet Mode" which limits the engine to 200 HP or so by never opening the secondary intake runners. Valet mode was toggled with a lock on the console, and the key was attached with a quick disconnect, so the owner could keep the valet key, but give the ignition key to the valet.

quote Originally posted by Will: Bascially, the ZR1 has a "Valet Mode" which limits the engine to 200 HP or so by never opening the secondary intake runners. Valet mode was toggled with a lock on the console, and the key was attached with a quick disconnect, so the owner could keep the valet key, but give the ignition key to the valet.

Thanks for the link, I've bookmarked it and will look into it, both the 6-spd transmission and the 6-spd change-over kit.

As for Valet Mode... like I would ever let anyone else drive my car! Heck, I don't let anyone else drive my 84 F-150

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1985 Pontiac Fiero 2M4
Soon to become the LT-5 powered Pontiac Fiero ZR

quote Originally posted by LT-5Fiero: 2) I had heard of the Getrag only supporting up to 350 ft-lbs with serious care. When I'm through with it, it will be getting well over 425 ft-lbs. If the Getrag will work, then I will use it. I was really looking for a 6-spd if at all possible. The thought of a 200 MPH Fiero is constantly dancing in my head , but then I remind myself I don't need a 6-spd to achieve that, the well-geared 4-spd/5-spd trannies in the GT40 took it to well above 200.

The Getrag, with a 7000rpm rev limit and 18" or larger wheels, will take you to 200mph if you've got the torque at 7K rpm to push all that air out of the way. The LT-5 doesn't make high peak torque out of the box, I believe it is only about 375fp. And it'll take it if you aren't trying to break it, my engine is rated for 430 ft-lbs and I haven't had any problems in 6k miles on street tires, but I also drive it intelligently. You might consider cryo or ultrasonic hardening if you insist on being abusive (banging gears, downshifting without rev matching, clutch pops, etc). Otherwise, it should be fine. And a SPEC clutch should be a drop-in.

quote Uniqueness, sheer power, the potential, and just the plain awesomeness of the look of the LT-5. Ever seen an LT-5 with all 16 of those intake runners chrome polished? I'm sorry, but it puts the LS1/LS6's looks to shame

It may look cool, but the sound of it would be even cooler. It is rare to hear an LT5 roaring by you wide open, but through my participation in Corvette club events with my '98 I've had the pleasure of watching and listening to ZR-1s blowing past me WFO at triple-digit speeds on the track. I even watched a beautiful black '95 be completely destroyed in an endo on turn 9 at Summit Point. They are awesome machines, but they'll bite.

You aren't the first one to consider this swap, though. I can promise you it's wrought with serious engineering challenges. You'd better start worrying right now about how you're gonna get that right-side head in there, you will have clearance problems even if you move it the standard 2 3/8" to the left. If you move it more than that you're going to have axle problems.

Dave

I've finally got some dimensions, thanks to CorvetteForums:

Length: 27"
Width: 27"
Height: 29"
Weight: 596 lbs

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1985 Pontiac Fiero 2M4
Soon to become the LT-5 powered Pontiac Fiero ZR

Holy crap, that thing's over a hundred pounds heavier than an iron SBC! I'd heard it was around six hundred pounds but nothing so precise. It's bigtime top-heavy too.

The other dimensions don't mean much without anything else for comparison, but I know it's a behemoth and those numbers sure sound like it.

Dave