Engine Swap Questions (Page 1/2)
1TrueJeff MAR 11, 08:00 PM
So, I am not actively planning to swap my engine at this time (I have the little 4 cylinder, and I don't need anything more than that at this time), but I do have some questions regarding doing them. How do you even research what kind of engine you can trade it out with? How do you know what fits? How do you know what engines can attack to the transmission? Do you typically swap the transmission too? Do you need to switch anything else out too? I knwo for some newer vehicles you have to get like a different fuel pump and injectors for some, so what other sorts of things need to be switched out?

I figure if the engine in mine ever dies I would totally consider putting something else in it, but i'm not just itching to switch it out.
FieroJimmy MAR 11, 09:12 PM

quote
Originally posted by 1TrueJeff:

So, I am not actively planning to swap my engine at this time (I have the little 4 cylinder, and I don't need anything more than that at this time), but I do have some questions regarding doing them. How do you even research what kind of engine you can trade it out with?



Welcome. For the most part, if you can think of it, someone has already swapped one into a Fiero. From a VW TDI or an Audi V8 to a Honda K series, to old school big block Pontiac V8s. Unless you are doing something really off the wall, or new, someone has already done the leg work.


quote
How do you know what fits?



As above, it has likely already been done, but basically, just measure the length and width of the engine and determine if it will fit inside the confines of the engine compartment. If it doesn't fit, can the engine compartment be modified to allow it to fit.


quote
How do you know what engines can attack to the transmission? Do you typically swap the transmission too?



It is usually easier to treat the engine and trans as a matched pair. Assuming the trans is a transverse unit. Bellhousing patterns for most engines and transmissions can be found on the internet. If necessary, you can run an adapter plate and custom flexplate/flywheel. With modern computer controlled transmissions, the controllers are frequently part of the engine control unit, so it is much simpler to just run the single computer.


quote
Do you need to switch anything else out too? I knwo for some newer vehicles you have to get like a different fuel pump and injectors for some, so what other sorts of things need to be switched out?



Do you NEED to switch anything else out? Outside of the typical powertrain related components (alternator, water pump, AC compressor, fuel pump if necessary, air intake, coolant lines, exhaust, etc.) No, not really. However, depending on your local emissions inspection regulations, you may have to swap a lot of other things. Rickady88GT has done some pretty well documented CA legal swaps. In CA you have to basically swap all the stock components from the air filter to the downstream O2 sensors, including the computers, in order to be legal. When you are doing work as extensive as an engine swap, it is often a good time to add or modify other things (project creep is a very real thing ).
1TrueJeff MAR 11, 09:25 PM
In Oklahoma we ditched vehicle inspections back when I was just a wee lad. So you can drive whatever redneck car or truck you want. I once saw someone driving about 25% of a car and the cops never pulled him over!

What about going from a manual trans to an auto?

Not having a garage or shop there is no way this is gonna happen for quite some time.
Patrick MAR 11, 10:01 PM

quote
Originally posted by 1TrueJeff:

What about going from a manual trans to an auto?



Why would you wish to reduce the fun of driving a sporty car?
FieroJimmy MAR 11, 10:42 PM

quote
Originally posted by 1TrueJeff:

What about going from a manual trans to an auto?



Manual to auto, or vice versa is a fairly complex swap. There are changes from the radiator to the cv shafts. A (non-exhaustive) list would include:

Radiator
steering column
shifter and cable(s)
ignition switch
trans cooler lines (if swapping to auto, clutch line if swapping to manual)
brake pedal
shifter surround
ecm (Auto ecms control torque converter lock-up, manual have the upshift light control)
wire harnesses as necessary (Manual has a clutch safety switch, and auto has a park/neutral switch on the trans. Also back-up light control is different)
CV shafts
transmission mounts
and probably a few other things I'm missing.

It's a great deal of work, but it is easily do-able. The hardest part of it is locating the necessary parts.
1TrueJeff MAR 11, 10:44 PM
Most things I saw online was that if you swapped it with a 3800sc that it was best to put an auto trans in, i have no idea why or how or anything like that, I just know what the internet told me
I plan to leave it as stock as possible

[This message has been edited by 1TrueJeff (edited 03-11-2022).]

Dennis LaGrua MAR 12, 07:43 AM

quote
Originally posted by Patrick:

Why would you wish to reduce the fun of driving a sporty car?



I won't claim that the Fiero autos with the three speed trans is the way to go but with the 4T60e or 4T65eHD that's a different story. Easier to drive, especially in traffic, and they eliminate typical problems with the Fiero clutch and shift systems that are not exactly excellent by any means. Then look at the availability of modern cars with manual transmissions and the choices are very few. You can't even order one on a new Corvette. Probably no demand.

------------------
" 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 "

FieroJimmy MAR 12, 09:04 AM

quote
Originally posted by 1TrueJeff:

Most things I saw online was that if you swapped it with a 3800sc that it was best to put an auto trans in, i have no idea why or how or anything like that, I just know what the internet told me
I plan to leave it as stock as possible




The thing about calling something "best" is that you really have to define the criteria you are using to establish your rankings.

Is it easiest/cheapest to run the 4T65E-HD that comes with the 3800SC? Yes. Custom trans mount brackets, shift linkage, and mix-and-match axles, and you're down the road.

To stay with the stock transmission you'll need custom PCM programming, a custom flywheel and a clutch that will hold ~400+hp.

With the 4T65E, you get a trans that is designed for the power levels developed by the 3800. The stock Fiero transmissions were intended to run behind an engine making ~150hp, and the 3800 starts at more than double that, and can easily go up from there.

There is a great deal of empirical evidence showing that the stock trans can survive much more power than originally designed for.

In the end, it mostly comes down to a question of which you prefer driving, and how much work you feel like doing. Starting with a stick shift it will be much less work to stay with a stick.

[This message has been edited by FieroJimmy (edited 03-12-2022).]

Patrick MAR 12, 05:07 PM

quote
Originally posted by Dennis LaGrua:

autos... they eliminate typical problems with the Fiero clutch and shift systems that are not exactly excellent by any means.



The biggest problem by far with Fiero manual transmissions was the single seal slave sucking in air. The dual-seal slave has eliminated that major issue.


quote
Originally posted by Dennis LaGrua:

Then look at the availability of modern cars with manual transmissions and the choices are very few. You can't even order one on a new Corvette. Probably no demand.



Automotive climate control, heated seats, collision avoidance systems... yes, I get it... people today are way too soft.
reinhart MAR 13, 06:53 AM

quote
Originally posted by Patrick:

Why would you wish to reduce the fun of driving a sporty car?



I know you're obsessed with the notion that stick over auto thing. However, I should point out that the stick of the 1980's is dinosaur technology. And it isn't even what is used in most high end sport cars or race cars today. Those cars use paddle shifting without a clutch, which is actually closer to an automatic than a stick. Pretend you're driving a Fiero automatic where you are moving the shifter from 1-2-D and downshifting via the shifter, and that's far closer to modern sports car paddle shifting than a 80's manual/clutch pedal arrangement.

So yea comparing a manual of 1985 to a modern sports car is not even close to the same thing. Nor is it even faster today. In fact if the Fiero automatic were a 5 speed with proper gearing rather than a 3 speed, it would be faster accelerating than the manual (the gearing of the 3 speed drops 3000 rpm? between shifts?) and auto not having to lift off the throttle between shifts. Or better yet a variable gear automatic would destroy an old school manual. Imagine the entire acceleration at peak power without having to shift any gears.