Which motor makes more horsepower. From what I’ve read the 4.9 is 200 H is that right? It doesn’t sound right so wanted to confirm how much horsepower the 4.9 caddy motor produces. Looking at eventually doing a motor swap and right now the 4.9 and 3800 supercharged is what I’m looking at.
The 3800SC (Series II L67) has 240hp and 280 ft/lbs of torque.
The 3800SC is going to be easier to do mods if that interests you at all. The potential output for this motor is very high. There are a lot of swap threads about both these motors. I would suggest searching and reading to figure out what it is you like best.
[This message has been edited by Spadesluck (edited 03-30-2019).]
The 4.9 is a cheap, lightweight, high torque V8 that is a lot of fun to drive, quite fuel efficient with the matching 4 speed auto, and almost always sounds good. It is not a high hp engine and those who have tried to make it into one, haven't been impressed with the results (head flow is the primary issue, followed closely by the intake, eventually the loose cylinder sleeves that are only held in place by the head bolt clamp pressure will limit reliability as hp increases).
The 3800SC is easily the most common swap. Over the years it has had the most vendor support for mounts, harness, performance upgrades, etc. It is a very versatile engine that can be built to 400+ hp and in stock form is very fuel efficient. The biggest two drawbacks are weight and and exhaust note.
I recommend you find people local with both swaps and see if you can get a ride in them and see which one you like better. There is more to enjoying a swapped car than the peak hp numbers.
Thank you for the info! My car has 204,000 miles on the original motor and still runs like a champ but always dreamed of putting a 3800 SC engine in it. I don’t have the capability of doing it but am looking at vendors that could do it eventually.
The 3800 has much more potential than the 4.9. It also has pretty good aftermarket support. But there is very little aftermarket support for the 4.9 V8, and it doesn't respond very well to performance upgrades. If you just want a cheap easy way to get V8 noises out of your Fiero, you might like the 4.9 V8. But if performance is more your thing, you'll do better with the 3800.
I have a 4.9 Formula and have built/driven several 3800SC. 4.9 power is instantaneous, due to the big torque at low rpm. And it sounds really good. The 3800SC takes longer to build power, they are fast, but then there is the exhaust sound and the whine of the supercharger.....two noises I personally don't like. Both are good drivetrain upgrades.
The 3800 has a pretty bland sounding exhaust note. Some people are OK with it, and some aren't.
Edit to add: You might want to visit YouTube and watch some 3800 Fiero videos to hear it for yourself.
Also note that some of the fastest Fieros (on the Quarter Mile List) are 3800 V6's. The fastest ones have turbos instead of blowers, but the supercharged ones are pretty fast too.
[This message has been edited by Blacktree (edited 03-31-2019).]
I have driven both the 4.9L and 3800SC and my driving impression is that the 4.9L gives you a better 1/8 mile ET while the 3800SC.may edge it out in the 1/4 mile. Now if you use the higher FDR of the 4T60e tranny as Joe is using they might be comparable. My 60K mile 4.9L powertrain will end up costing about half of what my 3800SC cost. Its also a much easier swap and in a cost per power comparison it wins out. The only thing that I dislike about the 4.9 swap is that the distance between the front firewall and the front exhaust manifold is very small, maybe an inch or so. This makes routing wires, fuel and and heater lines back there more difficult.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
The only thing that I dislike about the 4.9 swap is that the distance between the front firewall and the front exhaust manifold is very small, maybe an inch or so. This makes routing wires, fuel and and heater lines back there more difficult.
Your engine is mounted too far forward. I have plenty of room between manifold and front firewall. Do your drive axles have a slight forward angle?
I like a good exhaust sound but that’s not the number one priority.
If the #1 priority is power (hopefully with a reliable engine build), ask yourself how often you'll actually make use of all that power while puttering around town.
Now ask yourself how often you'll be hearing your engine while doing the same puttering around town.
I'd say for a lot of us older guys who grew up with V8's, the sound of a 3800sc is... ummm... less than desirable.
Yeah both posts make sense. I’ll have to YouTube the sound of a 4.9. It also depends on the exhaust obviously. I have a flow master on my 2.8 and it sounds pretty good for a 6 cylinder.
I have a flow master on my 2.8 and it sounds pretty good for a 6 cylinder.
Oh, I agree. The 2.8 sounds remarkably nice, especially for a 6-banger. (I have a Formula I've autocrossed, and it sounds great.) However, the 3800 has a reputation (well deserved, IMO) for sounding awful. It has little to do with the exhaust system... it's the firing order of the cylinders. Add a whining super-charger to the mix, and... well, you get the picture.
Yes, listening to some engines on YouTube will help you understand what several of us have been referring to. Try and find some videos where the engines are actually under load. Revving the crap out of a parked car is useless for hearing the true exhaust note.
That’s very true. I appreciate the feedback! I do appreciate a great sounding car. I think I took for granted how nice my 2.8 sounds. I’ll definitely check out YouTube videos. I’d like more horsepower but want it to sound good as well.
Here's an angle I have not dealt with but have heard about. Mechanics do NOT like working on the Cadillac motor. Even the factory installs. That was more than enough to steer me from the caddy motor. If it had a problem, expect worse problems finding someone to fix it. My first drive in practice was a Northstar. Crazy power. Good luck getting it serviced!!!
Thanks for the info. My experience in the past mechanics don’t like servicing a Fiero period. Maybe it’s changed now but I’ve had problems in the past with mechanics.
If you are going to go through the trouble to V8 swap it you might as well put an LS in it. Sure its probably harder to swap in than the 4.9 caddy but at least you have the power to make it worth it and endless aftermarket options.
1) I bolted it to a 5 speed - while it was fun I suspect that going the auto route would have been a far better choice since the 5 speed is not geared correctly for the 4.9l power band. 2) limited rpm - doesn't pull much after 4200 rpm, so if you go to the track you will find this is a limiting factor in the 4.9l
That being said, it was a cheap and easy swap - and for people in the crowds they think it is cool having a V8 stuffed into a Fiero. Would I do another 4.9l swap? Probably not, I would lean more towards the 3800SC and use an auto.
I like the 4.9 swap. It's not a race car, but it's quick, reliable, gets good gas mileage and sounds good. And it looks good in the engine bay. Using the 4T60E transmission that Cadillac put with the engine ensures there won't be problems with the transmission breaking. The weight of the drivetrain doesn't upset the handling, as it doesn't weigh much more than the stock drivetrain.
If you are going to go through the trouble to V8 swap it you might as well put an LS in it. Sure its probably harder to swap in than the 4.9 caddy but at least you have the power to make it worth it and endless aftermarket options.
Doing an LS swap is easily 4x (could be 10x depending on parts used) more expensive that the 4.9...
Like I suggested before do a search on motor swaps. You may even find you dont want either motor. There is no "best" motor as it all depends on what your goals are.
i dunno, i watched a bunch of videos on youtube and i think that the 3800 has a great sound. i know what you mean by the supercharger whine tho. i think that the sound of the car has more to do with the exhaust and muffler than the number of cylinders or the displacement jon
------------------ Astronomy says we will find a coded signal from outer space. Then we'll KNOW that life exists there, for coded signals aren't by chance.
Biology says there are coded genetic signals in every cell, but we KNOW that no intelligence created life.
I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!
Your engine is mounted too far forward. I have plenty of room between manifold and front firewall. Do your drive axles have a slight forward angle?
Now you've got me thinking. I'll have to check that one out this week and measure up. The trans uses stock 4T60 brackets and a WCF front mount with a generic energy suspension mount on the A/C compressor side. I use the 93 Deville Manifolds.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I have 2 of the 4.9 conversions, one 4spd auto and one 5 spd manual. The auto car is more fun at the 60 ft Grand Prix (average distance across the intersection) but the 5 spd just has that manual transmission thing going for it. They are both a lot of fun to drive and I don't prefer one over the other. Plus they both have that V8 rumble as I idle thru the car show parking lot. Always get lots of comments, "Hey that's not a V6, what do you have in that thing?"
