2.5L to 2.2L conversion

this would be way off in the future, but i'd like to run 12's in my shadow. i've read all over here that the 2.2L t2 is less prone to detonation and a stronger motor all around. If i wanted around 300-350 hp in my car should i build up the 2.5 or swap to the 2.2? Also what's involved in doing the swap? If i swap to say an 87 2.2L t2, do i run the wiring harness from that engine? do i run a computer made for that engine? all of this electrical stuff really confuses me, like what computer will work where and the differences in the wiring harnesses. btw. looking at hopefully using a stock garrett t03 for 20 or so psi. should i look into a hybrid instead? thanks for any help.

[H Bomb]

If am wrong someone please correct me. The reason the 2.2 is less resistant to detonation related failures is because the 2.5 piston is has a shorter hight above the ringland. Less metal to absorb heat and then run hotter. Check out www.thedodgegarage.com and get the scoop on that. You would need 2.2 crank, pistons and 89TII electronics (I believe the are both sbec units ) to do the swap.

All that being said forged pistons and a big intercooler and careful management of fuel can make a 2.5 fly.

Gary's site about is a great place to start.

T

[Mr P-body]

The way I look at it is both motors are prone to detonation because your dealing with extreme heat conditions. The best way to choose would be by application. If you run a semi heavy veh on the street I would go for the 2.5L because of is wide torq curve, and It will excellerate more quickly as you race short distances between stop light to stop light . If your building a lighter veh say like a glh or charger or put your car on a diet you could get away with the higher reving 2.2L . I prefer the 2.5L regarless because with proper tuning and good internal parts you can get the best of both worlds. A large cubic inch engine that turns rpm's and creates tons of power in a light car.

Also when you start getting into the simple mechanics of the motor as far as rod ratio and dwell time you will find that the 2.2L motor would be more prone to detonation because the piston hangs at the top of the bore longer as where to the 2.5L has a higher piston speed wich generaly beats the flame front as the ignition fires the air fuel charge, and creates less of a chance of detonation....maybe thats why the 2.2L has mor top ring land :big grin:

[crazymadbastard]

I think that if you run forged with the 2.5 you will be very happy. I have heard some rumors GaryD has some nice forged pistons to cure the detonation issues with the 2.5.

[glhsken]

Real life results tend to indicate your theories aren't quite right.

Are both motors prone to detonation. Well, any motor is that is not set-up right is. The difference is the word "susceptible". While either motor may be prone, The 2.5L is more vulnerable to damage.

The 2.5L was a compromise. Longer stroke left less room for the piston.. Much more compact. That is the reason the top land is shorter.

2.5L JE's with the top land peeled off is a terrible sight to see. To make a sturdier 2.5L piston, the entire pack needs to be moved down. RP has, or had, such a piston.

Even the best built 2.5's come no where near the RPM of the better built 2.2's (not saying they are revvers either). 2.5's do have monster torque.. but if a mild 2.2 can make 340 ft lbs and a built one makes 418 ft lbs, Why toss the extra 4-500 rpm of power band away??

[glhsken]

One more thing to think about...

How many 5 sp 2.5L cars are in the 11's... (1 I know of) how many 5 sp 2.2L's are?? 3 I know of.

Heavy?? Auto?? go 2.5L

Staying a 5 sp stick with a 2.2L

[Dion Ricketts]

Hey Ken,

Funny that you point out the number of 2.2's. vs. 2.5's. I was looking at the Dragtimes page that has been set up and it seems the 2.5's are out numbered 3:1, or maybe 4:1. The top spot is taken by a 2.5, though.

What about a heavier 5 speed car? I have been debating this for a little while and will probably just run the 2.2 (economics), but am always curious about other opinions. I have to say that Steve Menegan and Gary D's Daytona seem to do just fine with their 2.2's.

[glhsken]

The dragtimes page is wrong regarding Steve M's 3000lb GTC, It is a 2.2L. What was that question about a 5sp heavy car again??? "thumbs up

The TOP spot is taken by a 1700lb 2.5L AUTO. I'd hate to see his MPH with a 2.2L. One seriously fast car, in my opinion, the wrong motor. But that's just that, an opinion. Stephan has a seriously fast car there.

There is not a 5sp 2.5L there. James Reeves is the ONLY one I know of.. 2600lb Omni 2.5L 5sp 11.88 @ 116.5

I will be playing with a 2.2L 3000lb Shelby Z that is going auto... Should be interesting.

[Dion Ricketts]

Wow, I didn't even notice that it posted it as a 2.5. Maybe it said 2.2 before Mr. Menegan broke the 11 sec barrier and they updated the page.

Both Steve and Gary have shown, in my opinion, that the 2.5 isn't THE way to go (meaning there is no other way) in a heavier car. I suppose a 2.5 works great, the factory didn't turbo the 2.0 when they did the SRT-4, but a 2.4. On the other hand, the Salt Flat LeBaron (200mph car), use a detroked 2.2 for 2.0L. Either way, if my 2.2 will get me a mid 13 sec 1/4 mile, that's what I plan on using.

Thanks for the input Ken.

when you say heavy car are you referring to p-bodies? i take it, if i can get my hands on a 2.2 i should build that (for a street driven shadow 5 speed). i couldn't find the RP 2.5 pistons, maybe that solves my problem. i did find the p/n for for some mahle's though. as far as the swap is concerned, could i reuse the 2.5L block? or should i look at getting a stock 2.2 block? i have more questions but this is enough for now.

[glhsken]

P bodies aren't that heavy... 2750 is an average race weight.

Quote:

could i reuse the 2.5L block? or should i look at getting a stock 2.2 block?

Why not.. you'll need a 2.2 crank. If you are looking to make good power, go forged pistons.

I'm using a 90 tbi 2.2 liter common block in my current build-up.. Keeping the cast crank and working everything else. Wheel hp should be in the 320-330 hp range at 22 PSI boost.

Mahles are good pistons... They can take it (in 2.2L form) But insurance is always nice.

[LeGweg]

Quote:

The TOP spot is taken by a 1700lb 2.5L AUTO. I'd hate to see his MPH with a 2.2L. One seriously fast car, in my opinion, the wrong motor. But that's just that, an opinion. Stephan has a seriously fast car there.

It's a 2.2, not 2.5

[glhsken]

Cool.. then his listing needs to be changed as well... ALex, You listening??

[spoolboy]

Yeah, yeah... build 2.2's... 2.2's are great.....

I'll swap some 2.2 CB cranks for 2.5 CB cranks....

:big grin: :big grin: "thumbs up

[glhsken]

Quote:

Originally posted by spoolboy Yeah, yeah... build 2.2's... 2.2's are great..... I'll swap some 2.2 CB cranks for 2.5 CB cranks.... :big grin: :big grin: "thumbs up

LOL for 5 sp's yes... Auto's seem to like the 2.5's... hmmm wonder why...

Spoken like a 2.5L auto owner Dennis!!

How many 2.2cb cranks you have??