I have an 02 car and an "extra" 04 engine & tranny I was wondering the best way to put together the individual parts.

It is a given that I will use an early ecu. Regardless of the great number of the sofa crowd who say it doesn't work the people who have actually done it say it will. I don't believe 9,000 rpms will kill the 2.2, at least not as infrequently as I hit 9k. And I can always give myself an 8.5k limit so my occassional over rev is still only 9k.

Should I use an 02 engine and an 04 tranny or an 04 engine and the 02 tranny?

My thoughts are:

The 02 needs a little more bottom end grunt which the lower gearing of the 04 tranny could give.

The 04s run out of steam too rapidly with the 8k rev limit and the shorter gears but the longer gears of the 02 tranny should give some of that back and still leave you with a little more bottom end grunt than the stock 02.

Anyone done either of these who has some real world input instead of theory? Obviously I wouldn't be asking this if I could have found in on the search engine.

 

I'd use the '04 tranny regardless of which engine you use. I love it on my '02!

 

Good question.
I've seen AP2 trannys with AP1 engines, but not vise versa... Hrmm this one has me thinking. However, the proper & relevant feedback you are looking for can only come from someone who has done both, which is probably a hard find.

 

Well, I'm in my armchair, but:

1. Why not go for the bigger displacement of the '04?
2. I like the 9000 rpm '02 ECU, used as you describe.
3. No opinion on the trans.

 

Out of curiosity, can you really tell/feel much difference in performance?

I mean, 1st through 4th are only 4% shorter, 5th is only 1% shorter and 6th is actually 2% higher in gear ratios. Beyond seeing a 2 to 4 mph (that's a guess on my part) reduction in top speed at redline, I can't imagine that acceleration is effected that much.

No flame meant, just wondering!

Drive Safe,
Steve R.

 

As to whether I can tell the difference with the tranny the answer is I don't know, BUT sitting on my sofa and making grand pronouncements it would appear that the 4% difference would improve those cruising or off the line situations where the engine torque feels a little weak.

For me the small decrease in cruising rpm is a big plus since I normally cruise at 80-85 on the long Texas Highways.

The big reason for the 02 tranny on the 04 engine is that everyone I know who has an 04 and does any autocross or track events constantly complains that they run out of revs too quickly with the 04 gearing. To me it appears that the early engines would benefit from the later trannies and the later engines would be better matched to an early tranny.

I am definitely putting an 02 tranny on the 04 engine that I am putting in my Ultralite because I need the longer legs on the track and I don't care about 6th gear.

From those that have done it I know I will have to change the ecu to an 00-01 ecu because they run richer which is helpful with the larger displacement. When that time comes I am sure I can find someone to swap for my 02 ecu since it runs leaner and they supposedly dyno with better HP under the curve.

Back to the theory, I should also swap springs and possibly cams from the 02 to the 04 for the ultimate since I would be revving it higher than the stock limit, but then I wouldn't have a good combo to sell.

In case you weren't aware, the part numbers are different, although I haven't found anyone who has actually tested the springs to see what the difference is but scuttle butt says they are probably lighter weight.

I feel that whichever I do, I need to end up with a combo that someone else would want and would buy when I am through.

 

Wildncrazy, that is exacly why I installed an MY04 tranny in my MY02. I live in Houston, and 80-85 is the norm on the freeways. Now, I alos have 4.57 gears in my rear (4.10 stock)

 

I did a few other mods (clutch, header, test pipe) at the samie time, so I cannot say 'yes the 04 trans makes the car quicker while X'. The combination definitely accelerates better than before. The rpm reduction in 6th (since I also have 4.57's in the diff), and the associated mileage increase were the most obvious 'transmission only' effects.

 

I can't even imagine how many rpms you both are turning on the freeway with 4.57s!

I had figured that if I wanted to maximize acceleration then I could put in 4.30s with the 04 tranny and get the hwy rpms pretty well back to "stock".

So I guess everyone is saying to use the 02 engine and the 04 tranny not the otherway around.

That is certainly much easier.

 

5000rpm @ 80mph with the 4.57's
4700-4800rpm @ 80mph with the 4.57's and the '04 tranny.