Sounds odd considering the issues with the other Fiero... But I just purchased another one and happen to have a spare LS3 lying around (the wife took the car but I took the motor) From a 2012 2Ss Camaro.
What all needs to be done for me to drop it into the other 85 I just got. Currently is a 4 cylinder. Money isnt necessarily an issue but anybody have relative estimates for what it would take? Thanks
I keep reading people on this forum say that there is not a manual trans and/or axle setup for the Fiero that can handle the horsepower that an LS3 makes.
I've chased Jacks car, it's fast! The LS3 power is incredible on the Fiero chassis and when turned loose on the track at Watkins Glenn gives an unbelievable ride. He also has the one of the cleanest LS swaps out there, much to the credit of V8 Archie and Jack.
I keep reading people on this forum say that there is not a manual trans and/or axle setup for the Fiero that can handle the horsepower that an LS3 makes.
Is that wrong?
Well obviously the GM FWD transmissions are not designed for such high torque. But the F23 and F40 seem to be the favorites while staying with "economy" transmissions.
If you want to flog your V8 car with impunity, then you'll probably need one of the beefier longitudinal transmissions. Not that longtitudinal is inherently more robust than transverse, it's just that the available beefier transmissions happen to be longtitudinal.
Thanks guys. I'm going to get in contact with them soon than. I have been debating this project for awhile, but am stuck on getting a twin turbo 3800 setup on the other Fiero. I'm just happy to know that it can be done and its not a pipe-dream.
I keep reading people on this forum say that there is not a manual trans and/or axle setup for the Fiero that can handle the horsepower that an LS3 makes.
Is that wrong?
There are over 25 LS3/F40 Fieros running around the country. Only the LS7 with a supercharger has broken an axle (but he is also running something like 20x10 wheels too). Jack and I did multiple 1/4 mile passes on our LS Fieros few years ago at LS Fest in Bowling Green.
I have the smaller LS4 (382 whp, 420ish fwhp) with the F40, but I am over 42K miles on the swap, fourteen 1/4 mile passes, 30+ autocross events, and countless WOT blasts while driving. All w/o any transmission or axle issues. Eventually I will break an axle, but the combo has been very reliable for a long time. There are stock Fieros that haven't seen the reliability I have seen with the LS4/F40 combo.
Know what you mean, but hardly a pipe dream. Ask Jack. You might also check with him on the trans. I know it's a stick, just not sure if it's a Muncie or Getrag.
There are over 25 LS3/F40 Fieros running around the country. Only the LS7 with a supercharger has broken an axle (but he is also running something like 20x10 wheels too). Jack and I did multiple 1/4 mile passes on our LS Fieros few years ago at LS Fest in Bowling Green.
I have the smaller LS4 (382 whp, 420ish fwhp) with the F40, but I am over 42K miles on the swap, fourteen 1/4 mile passes, 30+ autocross events, and countless WOT blasts while driving. All w/o any transmission or axle issues. Eventually I will break an axle, but the combo has been very reliable for a long time. There are stock Fieros that haven't seen the reliability I have seen with the LS4/F40 combo.
The LS3 is great engine. I would have considered it, if there was a way that I could use the 4T65eHD. Those transmissions have been built to hold 1000 HP.
Isnt that the transmission from the GTPs? I want to be able to stay at the (roughly) 600 horsepower that this LS3 is currently at without snapping an axle and dying on the road, I wish that 1000 was a realistic number for this car. Unless it is and Im unaware haha.
Ive enjoyed the answers, they've been very helpful. This forum has saved me so many times haha. I appreciate the detailed responses y'all.
Isnt that the transmission from the GTPs? I want to be able to stay at the (roughly) 600 horsepower that this LS3 is currently at without snapping an axle and dying on the road, I wish that 1000 was a realistic number for this car. Unless it is and Im unaware haha.
Ive enjoyed the answers, they've been very helpful. This forum has saved me so many times haha. I appreciate the detailed responses y'all.
A stock LS3 is about 430hp, what did you do to get 600hp? If it is turbo, then you will have to replumb the turbo system. I like the supercharged version, not saying it is better, just saying that would be my preference.
I have an LS4 on the stock 4 speed 4tHD auto that came with it in the donor car, Mote Carlo SS. Not that different from the GTP, mainly mine has no "tap shift".
Originally posted by Rickady88GT: A stock LS3 is about 430hp, what did you do to get 600hp? If it is turbo, then you will have to replumb the turbo system. I like the supercharged version, not saying it is better, just saying that would be my preference.
Camshaft upgrade, some headwork, and RPM will get the LS3 over 600 flywheel hp naturally aspirated.
Camshaft upgrade, some headwork, and RPM will get the LS3 over 600 flywheel hp naturally aspirated.
So after boar and stroke are addressed, the same mods can be done on an LS4? I know 800hp is easy enough on race engines, but how streetable or "practical" is this on a street car?
[This message has been edited by Rickady88GT (edited 12-27-2017).]
Most ultra high HP production cars use a variety of stability and traction controls to make the cars streetable. Some of them even change the tune of the motor depending on the setting you choose. Most of that electronic wizardry is not available to us, so I would think you would need to have one tune for the street and one for the track if you you built up a monster HP motor. Easy to do with HP tuners and a laptop. Most of the high HP cars also can select all the aids to off, but they are not completely shut off.
[This message has been edited by wftb (edited 12-27-2017).]
Ok, did a short search for 600hp upgrades on the LS. Incredible to say the least. But my little LS4 is truly left behind on this train LOL.
I found a cartuning turbo kit that gets me 640 hp with 15lbs boost on my ls4. It's really streetable but I've been through three input shafts. One stock, one 3m, and one gm racing. I'm currently running a 3m input shaft cautiously.
Originally posted by Rickady88GT: Ok, did a short search for 600hp upgrades on the LS. Incredible to say the least. But my little LS4 is truly left behind on this train LOL.
There is very little difference between the LS family and the LS4, so nearly all the common upgrades will work for the LS4 as well. Max effort 5.3 NA builds just break the 500 hp mark, but the street manners on that engine will leave something to be desired. My LS4 has about 430 fwhp, but still has stock heads and stock LS2 intake and LS7 exhaust manifolds. If you want more cubes from the LS4, you can have the block re-sleeved, run a stroker crankshaft, or both... its just $$$.
A lot of people take bone stock 4.8 and 5.3L engines and throw an ebay turbo on them and make 600+ hp. If the engine lets go, they get another $500 engine and do it some more. There are quite a few 800+ hp 5.3s out there.
you can get new crate motors from GMPP. They have a stock LS3 - 430, a hot cam 480 and even a cam/heads - 525 version. Get an Archie kit. Here is a thread on my build.
There is very little difference between the LS family and the LS4, so nearly all the common upgrades will work for the LS4 as well. Max effort 5.3 NA builds just break the 500 hp mark, but the street manners on that engine will leave something to be desired. My LS4 has about 430 fwhp, but still has stock heads and stock LS2 intake and LS7 exhaust manifolds. If you want more cubes from the LS4, you can have the block re-sleeved, run a stroker crankshaft, or both... its just $$$.
A lot of people take bone stock 4.8 and 5.3L engines and throw an ebay turbo on them and make 600+ hp. If the engine lets go, they get another $500 engine and do it some more. There are quite a few 800+ hp 5.3s out there.
Do you have a link to a build thread for converting the LS4 block to an LS3 specs?
Originally posted by Rickady88GT: Do you have a link to a build thread for converting the LS4 block to an LS3 specs?
There have been a lot of people look into it, but no one has done it that I am aware of. Consensus is you have to wet sleeve the block (vs dry sleeving), which will set you back $3-4K + the rotating assy. Then you would still have to by the LS3 throttle body, heads, intake (another $1500 or so).
Several vendors sell a 4" stroker kit, which will make a 360 CID engine with the stock LS4 bore of 3.78. They run about $2200 and you will need the additional machining steps to shorten the crankshaft on both ends.
For the $$$, I would just get a 1/4" adapter plate, buy a LS3 (or similar RWD engine) short block (engine - heads and intake), cut the starter mount pad off the block, and install it with the LS4 heads, intake and accessory drive. You could likely just slot the holes in all your mounting brackets to get the extra space needed.
Any increase in displacement of the LS4 will also likely require upgrading many of the transmission parts ($3K rebuild)...
The most significant difference is bore and stroke.
Bore, yes. LS3 = 4.065 vs. 3.78 = LS4 Stroke, no. The LS1, LS2 (and all 6.0L engines), LS3 (and all 6.2L engines), and all 5.3L engines use the same 3.62" stroke.
There have been a lot of people look into it, but no one has done it that I am aware of. Consensus is you have to wet sleeve the block (vs dry sleeving), which will set you back $3-4K + the rotating assy. Then you would still have to by the LS3 throttle body, heads, intake (another $1500 or so).
Several vendors sell a 4" stroker kit, which will make a 360 CID engine with the stock LS4 bore of 3.78. They run about $2200 and you will need the additional machining steps to shorten the crankshaft on both ends.
For the $$$, I would just get a 1/4" adapter plate, buy a LS3 (or similar RWD engine) short block (engine - heads and intake), cut the starter mount pad off the block, and install it with the LS4 heads, intake and accessory drive. You could likely just slot the holes in all your mounting brackets to get the extra space needed.
Any increase in displacement of the LS4 will also likely require upgrading many of the transmission parts ($3K rebuild)...
Doesn't the LS4 have the LS6 heads, less the better valves and springs? CNC port and polish them and add better valves and springs, then swap the manifold to an LS6.
Originally posted by Rickady88GT: Doesn't the LS4 have the LS6 heads, less the better valves and springs? CNC port and polish them and add better valves and springs, then swap the manifold to an LS6.
Yes. I wouldn't spend the $ for the upgraded valves, they are just lighter. There are lots of engines spinning north of 7K rpm with stock non-sodium filled valves.
For the stock LS4 displacement, a $2500 set of ported/polished heads was good for 35 whp on a mild build. They would be worth more with larger displacement.
Once you start tallying up the cost to do a NA build for 500 hp, then tally up the cost for a turbo build capable of 600-700 with a bone stock 5.3L engine + camshaft, it is easy to see why turbos are so popular.
[This message has been edited by fieroguru (edited 12-31-2017).]
