2.5L to 2.2L conversion

[Turbolag87]

Ken is right, shifting a 2.5 at 6k will just hurt the motor and will produce anymore power. Brian slowes car is a good example. high flowing ported piece, with a fairly large turbo PEAKED at 5800rpm if i recall? If i stand correct, he is going 2.2 now to bring up his powerband. Will just have to see if his car goes quicker


Danny

[89daytonaTII]

i also shift my 2.2 just as the tach needle swings past the 5500 mark for my best times.

[Zed]

I've had 2.2's in H,G,P bodies all autos, and when they blew up and I swapped in my 2.5 (same motor in 3 cars now) they all went faster. I am however considering doing a 2.2 for my omni project with an auto, as I would like something that might hook up on the street.

[OmniSRT4]

Quote:

Originally posted by glhsken You are way off base... 5000-5200 max for the majority of the 2.5's out there.

I am not here to speculate. The fact is, you should shift at whaterver the optimum point on YOUR curve is in order to be at the best point in the next gear. In this case, that often means shifting well after your peak. As long as the gear muliplication in your curent gear is making more effective torque than what you would be making in the next gear, you shouldnt shift. Of course, the engine has its OWN limitations. In the case of the 2.5, 6k is all you would really want to do. At 5800 the pistons hit 4000FPM .

[OmniSRT4]

Quote:

Originally posted by Zed fastest times were shifting at 4700. Holding shifts to 6000 resulted in an extra 8 tenths in the quarter.

Wow, your car has no curve.

The only 2.5 dyno's I have seen were highly modified.

[OmniSRT4]

Quote:

Originally posted by glhsken Shifting my 2.2 below 5600 resulted in 2-3 tenths quicker e.t's (mostly stock car)

Do you have dyno plots with the same/similar setup? You can easily calculate your optimum shift point with a dyno chart.

Post one if you have it.

[OmniSRT4]

Quote:

Originally posted by Turbolag87 Ken is right, shifting a 2.5 at 6k will just hurt the motor and will produce anymore power. Brian slowes car is a good example. high flowing ported piece, with a fairly large turbo PEAKED at 5800rpm if i recall? If i stand correct, he is going 2.2 now to bring up his powerband. Will just have to see if his car goes quicker Danny

Well, yes and no. He has plans to go 2.2 but for now he is sticking with the 2.5. I assume he wants to hit 10's with the 2.5 first.

6k will not hurt the motor if its built well. However, as I clarified ealier, it all depends on YOUR power band. Myself, I have never owned a single 2.5 and the dyno charts I have seen were all from heavily modded 2.5's.

[OmniSRT4]

Quote:

Originally posted by Zed I've had 2.2's in H,G,P bodies all autos, and when they blew up and I swapped in my 2.5 (same motor in 3 cars now) they all went faster. I am however considering doing a 2.2 for my omni project with an auto, as I would like something that might hook up on the street.

I would like to see anyones dyno charts for their 2.2 and 2.5 motors. Just include with it the current mods. If the 2.5 (without heavy mods) has as weak of a curve as I am hearing, I definitely dont want to use one.

I do remember seeing Brians chart and being surprised how quickly and rapidly the curve downturned.

[glhsken]

Quote:

Originally posted by Akuma Do you have dyno plots with the same/similar setup? You can easily calculate your optimum shift point with a dyno chart. Post one if you have it.

I have dyno plots from a heavily modified 2.5, A 2.5 modified almost exactly like mine, A heavily modified 2.2 and Mine.

They are all posted... That IS how we derived the shift points.

[OmniSRT4]

Quote:

Originally posted by glhsken I have dyno plots from a heavily modified 2.5, A 2.5 modified almost exactly like mine, A heavily modified 2.2 and Mine. They are all posted... That IS how we derived the shift points.

Posted where?

Ive been trying to find varying dyno plots but havent had much luck.

[Aries_Turbo]

if i remember correctly andy (badandy) got his 13.0X at sdac when shifting at 4X00 but obviously his combo is suited for a 2.5's torque (fat car and auto).

Brian

[MachineHead]

Quote:

I do remember seeing Brians chart and being surprised how quickly and rapidly the curve downturned

He didnt really have a torque "curve". It looked more like a steep hill-going down. Nearly 500 ft/lbs of torque at 2600 rpm and drops very steadily to 250 ft/lbs at 7000 rpm.

That being said, I am still going neon head/ 2.5.

[OmniSRT4]

Quote:

Originally posted by MachineHead He didnt really have a torque "curve". It looked more like a steep hill-going down. Nearly 500 ft/lbs of torque at 2600 rpm and drops very steadily to 250 ft/lbs at 7000 rpm.

Indeed, it looked more like a hill.

Quote:

That being said, I am still going neon head/ 2.5.

Well, we can compare later because I am using a 2.2 w/ Neon head. It looks like I am going to build a "Stage 1" setup so I can get something on the road soon. I will then start work on the "Stage 2".

[Dion Ricketts]

Well, if both the 2.2 and 2.5 are somewhat rpm limited, what about destroking a 2.2? Has anybody gone down that road?

Just an oddball thought.

[MachineHead]

Quote:

Well, if both the 2.2 and 2.5 are somewhat rpm limited, what about destroking a 2.2? Has anybody gone down that road?

Here is a link to a car with a destroked 2.2

http://www.thedodgegarage.com/turbo_imsa.html

I heard the car was destroked to 2.0.