T2 2.2 to 2.5 conversion how much HP gain?

[glhsken]

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For these guys price = quality. Most of the guys that are hung up on the 2.2 have not driven/ridden in a well built 2.5.

I guess the 2.5 I get rides in isn't well built.

I think something will happen in the next 2 months that will have people questioning the 2.2 v/s 2.5 thing again.

As for the $$$ invested... Nope, I have a fresh start. Had my choice of whatever combo I wanted. I went 2.2 for my own reasons, nothing to do with anything spent in the past.

Went 108.8 on 14 psi of boost with a 2600lb 2.2L car... 13.02 it would light the tires at 75-80 on the highway.

Dyno plots tell a different story above 5k rpm.

[glhsken]

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Originally posted by spoolboy A 2.5 at 4840rpm moves the same amount of air as a 2.2 @ 5500rpm. A 2.5 at 2500rpm is the same as a 2.2 @ 2840rpm. Take a 2.2 dyno, and a 2.5 dyno. Adjust 2.5 dyno with a graphics program so that when you overlay the graphs, the 4840rpm and 5500rpm line up and 2500 and 2840 line up. See what it looks like then. The power drops off due to restriction. Unrestrict it and things change drastically. You gotta find the restriction. Camshaft is a good place where most don't look. With camshaft needs to come compression.

Of course it's about restrictions. If the 2.5 didn't have more, I wouldn't have to "adjust" dyno plots so points 660 rpm from each other are overlapped..

That's a heckuva lot of rpm to give up... so far no one has solved nor are the parts available to remove it.

[spoolboy]

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Originally posted by glhsken I guess the 2.5 I get rides in isn't well built. Dyno plots tell a different story above 5k rpm.

If you're talking about Reeve's car, it is most definitely well built!

"thumbs up

Just because it goes flat up high doesn't mean anything to the dragstrip.

Look at the dynographs and pick a shift point. Pick a trans and find the rpm recovery points (where the tach lands after a shift).

Crop that area on both dyno graphs with a graphics editor of your choice.

Compare now.

[glhsken]

But of course.. James car.

No need for theoretical cut and paste. we will have almost identical cars 2.2/2.5L mod for mod come springtime.

Should be fun..

[spoolboy]

If I could make 300hp at 1500rpm, I would. I'd have to make 1050ftlbs of torque to do it though.

High RPM? Why?

I heard a good one the other day.

Question:"What's RPM stand for?"


Answer: "Ruins People's Motors"


If you don't get it, well, I can't explain it any other way. That's why I haven't posted in this thread in a while.



Got a 2.5 crank to trade me for a 2.2 crank yet? :big grin:

Not trying to be a jerk, just a bit frustrated.

AREA UNDER THE CURVE IS WHAT IT'S ABOUT

[spoolboy]

PS, the shift light comes on at 4800rpm in Dad's 11 second car.

[glhsken]

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AREA UNDER THE CURVE IS WHAT IT'S ABOUT

Couldn't agree more... Neither motor has

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Answer: "Ruins People's Motors"

type rpm. We do use the plots to determine shift points for our cars.

Last one you should be frustrated at is me... I make points both ways.

Bearings also take a terrific pounding at low rpm high torque. Works both ways.

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If you don't get it, well, I can't explain it any other way.

You don't need to. I respect your viewpoints and experience we don't have to have the same.

As soon as I find a 2.5L crank, it's yours...

This thread is nothing more than pro's and cons for both motors. They both have each.

[glhsken]

BTW, I put a 2.5L into my convertible for a reason. It won't be modded and I want the "grunt" that motor has in it.

[4sfed4]

Quote:

Originally posted by spoolboy If I could make 300hp at 1500rpm, I would. I'd have to make 1050ftlbs of torque to do it though. High RPM? Why? I heard a good one the other day. Question:"What's RPM stand for?" Answer: "Ruins People's Motors" If you don't get it, well, I can't explain it any other way. That's why I haven't posted in this thread in a while. Not trying to be a jerk, just a bit frustrated. AREA UNDER THE CURVE IS WHAT IT'S ABOUT

I agree with both sides of this discussion and really only have one thing to add.

Making all this torque when you have no rpm to play with has a limit. Try making 450 + ft lb for any length of time. Within a just a very few miles, the rings wont be very happy.

Headgaskets will also have a shorter life as well and bearings take a brutal beating.

Unfortunately, Ive learned both these things the hard way.

[spoolboy]

<threadjack>

You still running the clutch I recommended, 4sfed4?

</threadjack>

[4sfed4]

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Originally posted by spoolboy <threadjack> You still running the clutch I recommended, 4sfed4? </threadjack>

I think that was on my old R/T. That clutch worked great.

Ive got what I believe is referred to as the Relentless Performance Stage 2 in my car now and it has held everything Ive thrown at it.

Self enlightenment question here, not trying to jump into this argument. Why is low RPM/high torque bad on the bearings? Is it just because the oil pressure is lower at low RPM's? And it really doesn't make sense to me why that would be bad on the rings. I always thought it was harder on rings/pistons when they were moving too fast (such as high RPM in a long stroke engine like the 2.5).
I chose a 2.5 for myself simply because I have a very heavy car (88 Daytona) and at the moment at least, I have an automatic tranny leaching power from me. Should be easy enough to swap in a 2.2 crank and pistons if I ever decide it was the wrong choice.

[Brian Putman]

I remember racing my friends 340 Demon with my 360 powered Dart a long time ago(basically same weight cars). The drivetrain on the cars were identical, same trans, gearing,tire size, converter stall, etc. The engines had the same basic heads & exhaust. My engine(360 still had the stock cam. It would only rev to 5000rpm. The 340 had a larger than stock cam and 1.5 points more compression and would easily rev to 6500rpm. No doubt the 340 was making more peak HP than my 360. What happened, I ran off and left his butt!!! Sure he could eventually catch me, but by then the 1/4 would be over. That made me a believer in a longer stroke engine. My belief is build torque as quick and for as long as possible and horsepower will come. I personally have never seen a larger engine built & tuned similar to a smaller one run slower in the same or similar car.. Even though we have forced induction there is still no replacement for displacement! I have been thinking about going to a 2.5 for a while now, and I believe it will out do the 2.2 I was using. The 2.5 will use the same head as the 2.2 I was running. I will be very surprised if the 2.5 runs slower. Torque causes excelleration, HP merely sustains speed. Although both are needed.

[4sfed4]

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Originally posted by UnaClocker Why is low RPM/high torque bad on the bearings?

High torque = high cylinder pressure = lots of force on the rod which the bearings have to "bear".

[Ben Paquin]

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Originally posted by 4sfed4 I agree with both sides of this discussion and really only have one thing to add. Making all this torque when you have no rpm to play with has a limit. Try making 450 + ft lb for any length of time. Within a just a very few miles, the rings wont be very happy. Headgaskets will also have a shorter life as well and bearings take a brutal beating. Unfortunately, Ive learned both these things the hard way.

I completely agree here. The 2.5's strength is also it's weakness. High torque is what kills our engines in my opinion. For the reasons already mentioned and the fact that the 2.5 is more prone to detonation because of the excess torque it makes.

It doesn't change the fact that a 2.5 at the same boost level should walk a 2.2 anytime. But I find the 2.2 can take more boost and abuse than a 2.5. This is where the 2.2 shines.