Hello everyone. Been lurking for a while and gathering info. Awesome site to come to for a Fiero education. Can someone tell me if the 4.5l install is basically the same as the 4.9? The engine is out of a 1991 Allante. I've found tons of info on the 4.9 swap but nothing on the 4.5. I have a 1984 four cylinder. I'm not even sure if the swap is feasible at all on that year Fiero. Any info would be appreciated.
Welcome friend. You've come to the right place. Lots of engine swaps have been done on this site. First we need to know what transmission your 4 cylinder 84 Fiero has. Automatic or stick?
** I'm sure others will chime in with useful information for all your questions as well.
If it's a stick go to the front of car and lift hood. On driver side fender well you will see a white sticker with a bunch of numbers & letters on it. Look very carefully for 3 characters showing MY8. Take pic and upload it. If you see the MY8 designation all is not lost. This was the 4 speed Economy transmission for 1984 only. It has a weak case and the thought of connecting a more powerful engine to it is frightening at the least.
I have a spare M17 4 speed with 88k gentle miles on it that is a much stronger transmission. If interested just PM me and perhaps we can cut a deal or swap, trade, etc. If you have an automatic or don't see MY8 anywhere then I refer you back to line ** of this post.
Again welcome to the forum. Spoon
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
If you're into 4 speeds, a franken-gearbox with the M17 case, 1st gear and 2nd gear with the MY8 3rd, 4th and final drive is basically the ideal stickshift transmission for a 4.5/4.9.
The Allante 4.5 will have the Allante intake, which is different than the PFI 4.5/4.9 intake. Beyond that, the 4.5 & 4.9 swaps should be identical.
All 84 manuals have a smooth case. The ribbed case was introduced in 85.
One issue you will have is the location of the 84 C-500 connector, it should be moved to the later model location by extending the wiring. The 84 also has only one fuel injector power feed, and no Battery Junction Terminal, which is easy to add.
My Fiero is a standard four speed. The only designation i could find with "m" as a starting letter were M19 and MM4. Thank-you for responding. This is gonna be a winter project but I don't want to get too far over my head.
The standard 4-speed (M19) has a 4.10/1 final drive. Its not ideal for a low revving, torquey engine like the 4.5. I would suggest going with the later 4-speed (M17, 3.65/1), as no changes to the shifter, cables, mounts or backup light wiring will be needed.
Hi Pauljt, The Allante engine you speak of is a great engine for a Fiero swap. It has the same big valve heads and compression as the 4.9 but has a shorter stroke. This allows for more revs. Swap is the same between the 4.5 and 4.9 unless you go manual. The 4.5 engine is externally balanced on the back half of the crank and internally balanced on the front part of the crankshaft. Therefore the two engines have different balance requirements. Bring your 4.5 engines flexplate and the flywheel you plan on using to your local machine shop and have them match balanced. Now you can pretty much use any of the Fiero and related transmissions. Good luck! Cheers, John
[This message has been edited by Johns 4.9 (edited 09-20-2019).]
My research tells me that the M17 transmission is from the 86 model . What about the 85 four speed....or is that one the same as the 84 with the exception of the beefed up casing?
Ay yi yi!!! Thank-you. I sure don't mind getting schooled on this particular playing field. I'm generally accustomed to having the answers (31 years as a millwright and 10 as a motorcycle mechanic) but I am definitely on "terra non firma" with this project that I'm hoping to get into. I'll keep doing research and asking questions here to verify.
Thank you Johns 4.9. I've decided the next swap I'm going to do will be a 4.5 Allante engine with the Getrag in my Formula. I've done a 4.9 in the past so I'm familiar with the process but that bit about the balancing is very helpful.
Also, with the ISC on the Allante, what are my options for fuel injection control? Am I relegated to the Caddy ECM?
Glad I could help, Rick. You don't want to use an aluminum flywheel with the 4.5 engine. Not enough material mass to remove to balance the engine. My engine balancer/machinist had to add Tungsten to the rear crankshaft weights to get it to balance. It was worth it and my customers 4.5 Stage III with the aluminum flywheel just screams! I can't help you out with your fuel injection. Just not my thing, 90's fuel injection. But there are several guy on this forum that are very good with the Allante FI. Radar is very helpful and others. Cheers
If you're going manual for sure, avoid the isuzu 5spd from the 87&88 4cyl cars. I was told I'd kill mine, and I did. 2nd gear is a weak spot and unfortunately the most fun gear to lean into. I documented my swap to try and help others doing the caddy 4.9 swap here; https://www.fiero.nl/forum/Forum2/HTML/122389.html
Being allante and 84, there will be differences, but hopefully the rest might be useful to you
Reallybig, I must be the luckiest guy in the world. I have had 4 SBCs and one Cadillac 4.9 in my Fiero all using the same 1985 Isuzu transmission. I have never had a problem in over twenty years. Is there a difference between early Isuzu 5 speeds and later model ones? Thanks Cheers
Thank you Johns 4.9. I've decided the next swap I'm going to do will be a 4.5 Allante engine with the Getrag in my Formula. I've done a 4.9 in the past so I'm familiar with the process but that bit about the balancing is very helpful.
Also, with the ISC on the Allante, what are my options for fuel injection control? Am I relegated to the Caddy ECM?
-Rick Stewart
The ISC's on both th 4.9L and 4.5L Allante engines are the same. As you've seen on your 4.9L they are actually idle speed motors and the only ECM's that can control them are the specific Cadillac ECM's. I could be wrong, but I doubt that the popular Chevy GM's like the 730 are capable of controlling them. On the plus side I see nothing wrong with the Cadillac ECM's as they can be programmed almost as easily as most other GM ECM's. With the Allante ECM you should be fine.
------------------ " 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 PCM that will work the Caddy ISC is the Caddy PCM. I've got a 7730, that I'm planning to adapt to my 4.9, but it will require a different throttle body. I'm thinking 3800SC or Northstar. Keep in mind that the Allante intake has a 2 barrel "staged" throttle body (like half of a quadrajet), that orients one port above the other. You will need an adapter to mount any kind of "round" throttle body to the intake. (Or a dual blade 305 or 350 TPI throttle body may work. The adapter should be much less complicated.)
Dennis, my 4.9 had an Allante intake but back in the day, the only one who could program it was Rockcrawl. We only got a very basic tune, just enough to get the car running (and running VERY rich) before Rockcrawl disappeared. But I've been in touch with a forum member in Indiana recently who can program Allante chips so I should be good to go this time around.
Originally posted by V8 Formula: ... just enough to get the car running (and running VERY rich) before Rockcrawl disappeared....
The "running rich" was due to the fact that the 4.9 IAT sensor is in the lower intake, and the Allante IAT sensor is in the upper plenum. The 4.9 tune is looking for much higher temps than the Allante sensor was providing. The ECM thought that the engine - or at least the ambient air - was very cold. I imported the IAT tables - and most other tables - from the Allante tune, into the 4.9 tune. It was quite close, after a slight upward tweak to the Base Pulse Constant. My 4.9/Allante runs ~127-128 BLM while cruising. At least it did the last time I scanned it. I also recently saw 24+ mpg, with a Getrag, on the way back from Asheville to west GA, at 80-85 MPH, or so.
[This message has been edited by Raydar (edited 10-13-2019).]
The only PCM that will work the Caddy ISC is the Caddy PCM. I've got a 7730, that I'm planning to adapt to my 4.9, but it will require a different throttle body. I'm thinking 3800SC or Northstar. Keep in mind that the Allante intake has a 2 barrel "staged" throttle body (like half of a quadrajet), that orients one port above the other. You will need an adapter to mount any kind of "round" throttle body to the intake. (Or a dual blade 305 or 350 TPI throttle body may work. The adapter should be much less complicated.)
Like yourself I have the tuning software for the Cadillac PCM. From what I have found on other tunes, if you change the TB the fuel tables must be adjusted as the TPS reading relative to air flow is different. I noticed this phenomenon on my 3800SC where the much larger N* TB gave more air flow at lower TPS readings (than the 3800 TB) but because it is OBDII I just had to adjust the TPS % table values and the problem was solved. .
------------------ " 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 "
At the risk of having "manual" purists boo and hiss at me I've got to ask. What about the Allante transmission? I think 4t60 f7 is the designation. I have the engine and tranny in my shop now. Also have the ecm and harnesses. I'm on a pretty steep learning curve right now and my brain is starting to hurt but enjoying the research side of this project just the same. Appreciate any thoughts or input on installing the 4.5 with its original transmission.
If everything is installed as it was removed from the donor, it ought to work as well as the 4.9/Deville package that most everyone has been using.
Trying to adapt across platforms can sometimes be difficult. I had an Allante tune that I thought about using with my 4.9, when I converted to the manual trans. My reasoning was that the F7 seemed to have fewer inputs and controlled devices than the 4T60E, so, fewer inputs and outputs to be "missed" by the PCM when the automatic went away. The transition was not as "seamless" as I had hoped it would be. I ended up going back to the Deville tune, and modified it to work with the manual.
I suppose my point is that the closer to original the whole package is, the better it should work.
quote
Originally posted by Pauljt:
At the risk of having "manual" purists boo and hiss at me ...
I've got a manual but, to be fair, it's a huge compromise. The gearing is a long way from "ideal", for the Caddy's tractor-like torque. I can't fault anyone who prefers the automatic. I just find the manual more fun to drive (at least for me) even with its shortcomings. As always, YMMV.
[This message has been edited by Raydar (edited 10-14-2019).]
The 4T60 is a good transmission with excellent gearing for the application, better than the Deville gearing used with the 4.9. IIRC, the Allante used the same gearing used in the later Seville setup, with 35/35 chain sprockets and a 3.33 final. The transmission is a good choice and will take a beating.
[This message has been edited by olejoedad (edited 10-15-2019).]
Been continuing my crash course on this engine swap. I've done a hell of a lot of reading. Mostly on this forum, including archives. The 91 Allante would have been equipped with a bcm I believe. So I am assuming that my ecm would be looking for all kinds of inputs from that module if installed as is? Is this one of the issues that would be solved by having the ecm re-programmed?
Ran into a bit of a snag with the ecm . Talked to Ryan at Sinister and gave him my numbers. Serv #1227750 and chip ADBC 6501. Apparently these numbers are from a 1987 4.1l Allante. Doesn't make sense to me. It was included with the engine, tranny and wiring I got from the previous owner. Anyone know what should be the numbers for a 91 Allante?
Never mind. I found and verified the 1991 numbers. (2240). I'm beginning to get a real bad feeling about the engine and tranny I bought. Are there any physical differences between the 4.1 and 4.5 Allante engines? I have various numbers from the engine but can't seem to find out how to interpret them.
Pauljt, What are the part numbers on the heads and the part number on the lower intake manifold? I can tell from those number which engine it is. Cheers, John
Ok. I have verified those numbers as belonging to the 90-92 family of 4.5l Allantes. I have no idea why there is a discrepancy in the ecm numbers. I've spoken to the gentleman that removed it all and he verifies that it all came out of the same 91 Allante.
Could be the manufacturer just reused some stuff or it was replaced at some point with the wrong one.
Could be. And it may have worked fine in the 91 Allante, but the problem is that when I checked with Ryan at Sinister he could do nothing with that ecm as far as re-programming goes. Which leaves me doing more research ,I guess, to see if another ecm might work in my 4.5 Fiero swap.
Could be. And it may have worked fine in the 91 Allante, but the problem is that when I checked with Ryan at Sinister he could do nothing with that ecm as far as re-programming goes. Which leaves me doing more research ,I guess, to see if another ecm might work in my 4.5 Fiero swap.
The 2240 was used in the Allante, as well as the 4.9 Devilles and etc. They are pretty common and not absurdly expensive. (At least mine wasn't.) You should be able to start with the base Allante PROM, and run with it, from there. If you need a copy of the stock Allante tune, for the 2240, please let me know. (Ryan probably already has it, however.)
Edit - the 1227750 is all over the internet as a replacement ECM for the Allante, including the later years, like yours. There is a good possibility that it is a Service Replacement part for the 2240.
Check this out. These are all the Cadillac definition files available for the Caddy 4.5 and 4.9, from Tunercat. It does not list yours, but that doesn't surprise me. These files are just about always a work in progress, as they discover new combinations.
***This definition file lists "manual", but I believe that is an error. I looked at the PROM info, and there is no manual option. Not sure what that's about.
[This message has been edited by Raydar (edited 10-20-2019).]
Thanks much for the info. The ECM serv number 1227750 is only part of the problem I have. Although I'm glad to hear it's being used in later year applications. The chip in the darn thing is ADBC 6501. Which apparently is from an 87 4.1 Allante. Ryan says he can't do anything with this or any other 4.1. Not sure if that means it can't be done or just that he doesn't do it.
Hi Pauljt,
