I was wondering, I know the base hp on the 4.5 is 180hp and the 4.9 is 200hp...... but when the 4.5 was used in the Allante, it had 200hp....equal to that of the 4.9...... what was changed to get this extra power? and can those parts be put on a 4.9 to get even more power?
__________________ ~ Rick
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~1994 Isuzu Amigo - Everything but roadtrips (unless trailer is in tow)
~1996 Lincoln Town Car Signature Series - The roadtrip machine AKA "Mafia Mobile"
hehe, man your just like me when i first got my coupe. One of the biggest differances with the allante engine is the intake, its TPI insted of PFI, it also has more of a newer TB style unlike our carb looking TB. Iam not sure if thats where the 20hp comes from though. Also finding one would be really hard and wouldnt be cheap. That and i dont even know how hard it is to go from PFI to TPI. hey you still got 20hp on me, i have the 4.5 in mine, thinking about converiting it to a 4.9 some day.
Yeah the 4.9 has 20 more hp and 20 more ft lbs of tourqe..... I perosnally don't like the nose/hood of the '87-'90 DeVille..... just not my type, I like the grille/hood of the '91-'93, but I think it can be switched over...
Are you sure that's not a picture of the HT4100 instead of the 4.5?
I dunno if the intake gave it the extra power or what, maybe someone else does?
Yeah the 4.9 has 20 more hp and 20 more ft lbs of tourqe..... I perosnally don't like the nose/hood of the '87-'90 DeVille..... just not my type, I like the grille/hood of the '91-'93, but I think it can be switched over...
Are you sure that's not a picture of the HT4100 instead of the 4.5?
I dunno if the intake gave it the extra power or what, maybe someone else does?
I have some limited experience (I just finished rebuilding the 4.5 in an '89 Allante, but haven't yet started it). From checking www.gmpartsdirect.com 's catalog, it appears that many, if not most of the internal part differences between the Allante 4.5 and the "standard" 4.5 were incorporated into the 4.9 (except the rods, liners and crank, of course). The intake is the major difference between the Allante and the others. It is port injected, but I don't know if it is technically "tuned port injected", although since it has intake runners, like the TPI corvette, I suppose it is.
You may want to check some of the Fiero boards. A lot of those guys are swapping Cadillac 4.x engines into Fieros and they do a lot of part interchanging. Seems to me I remember something about there being some port differences between the heads and the intake on non-Allante 4.5 engines, but I think the 4.9's would work with the Allante heads.
One thing I find interesting is that the Allante intake is very similar in design to the Mustang 5.0 of the same era. Are those (Mustangs) considered TPI?
kinda OT, but my friends said, "PFI, is that pretty F'n intimadating"
So how hard would it be to put an allante intake manifold on my 4.5?
Physically, assuming the ports match up (see above), all you need to do is replace the lower intake with an Allante lower intake, then bolt the Allante upper intake to the upper one.
The problem/challenge is the ECM. I don't have a clue how it would react.
