4.5l Allante engine (Page 3/6)
V8 Formula OCT 07, 11:52 PM
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.

Will, good idea!

-Rick
olejoedad OCT 08, 06:09 AM
Ryan at Sinister Performance can tune the Caddy ECM.
V8 Formula OCT 08, 11:57 PM

quote
Ryan at Sinister Performance can tune the Caddy ECM.



Yessir, that's the one.
Raydar OCT 13, 01:46 PM

quote
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).]

Raydar OCT 13, 01:49 PM

quote
Originally posted by Will:

You could also keep the Caddy throttle, ditch the ISM and run a remote mounted IAC into a large vacuum port.



That's a thought. I like it.
Dennis LaGrua OCT 13, 08:55 PM

quote
Originally posted by Raydar:

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 "

Pauljt OCT 14, 08:37 PM
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.
Raydar OCT 14, 09:24 PM
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).]

olejoedad OCT 15, 07:59 AM
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).]

Pauljt OCT 16, 10:44 PM
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?