Running a 2.5 instead of 2.2

[3Bar_Mopar]

I've looked thru a lot of 2.2 and 2.5 dyno sheets. There are only a handful of people able to make a 2.5 breath up top. Most experienced what I had, which is great low end torque, power dies around 3500rpm.

I'm no head porting master by any stretch....my 2.5 in my Sundance would pull hard to redline...self ported head and '88 roller cam and Enforcer turbo....I've smoked the tires hard in 2nd and bounced it off the limiter on accident. Car was a monster on the highway too. Before I swapped the head, turbo, swingvalve and exhaust it would fall on it's face over 4K.

[3Bar_Mopar]

A big problem people have with their 2.2 to 2.5 swaps and vice versa swaps, is that these piles of junk get tuned based on feelings (or not tuned at all, run on the wrong electronics, etc) and then MYTHteries start from there. With decades of bad advice and bad builds, anyone who does succeed is seen as an oddball.

If you shift because you don't feel torque increasing, have fun losing. Vigo has not completely given up the desire to give advice but I see it as pointless in these threads. What people use to say they love a 2.2 over a 2.5 technically puts them on the Honda bandwagon...something they will hate on by all of a sudden pretending to be a 2.5 fan. Or people could just understand a bit more about powerbands and how they apply real power to the ground and not feelings.

QFT...nailed it.

[bfarroo]

I personally like the 2.5. My DD spirit was a inter cooled 2.5 auto with .91 transfer gears and it was a great around town car. As others have said you can feel the limitations of the stock head in the high RPMs. Now the ported neon head on the 2.5 in my Daytona just keeps pulling to the 6800 RPM limiter. I've thought about raising it more but get a little afraid to spin it that high. They are really different animals and you need to decide what you want from the motor and go form there.

[turbovanman²]

Now the ported neon head on the 2.5 in my Daytona just keeps pulling to the 6800 RPM limiter. I've thought about raising it more but get a little afraid to spin it that high. .

Keep spinning it, I ran mine to 7500 all the time, never had a rod/bearing/piston issue but it was balanced, Eagle rods and forged pistons.

[Vigo]

2.4s have almost the same geometry as 2.5s and JT and Turboshad both shifted theirs in the mid 7k's while running 10s. I've revved my 2.4 past 7k in neutral looking for a rev limiter when I first got it.

I'd be pretty comfortable raising the rev limiter as long as you are still making power!

[3Bar_Mopar]

What if anything has to be done to the bottom end on a 2.4 to rev past 7K? I know a guy who swapped a couple 2.4s into a Neon and it ate rod bearings regularly because he loved to rev it to 7 grand with a MP computer

2.4s have almost the same geometry as 2.5s and JT and Turboshad both shifted theirs in the mid 7k's while running 10s. I've revved my 2.4 past 7k in neutral looking for a rev limiter when I first got it.

I'd be pretty comfortable raising the rev limiter as long as you are still making power!

[turbovanman²]

I think a bedplate is mandated but your the first I've heard of eating bearings at only 7K. They are factory redlined around 6500 IIRC.

[Ondonti]

What if anything has to be done to the bottom end on a 2.4 to rev past 7K? I know a guy who swapped a couple 2.4s into a Neon and it ate rod bearings regularly because he loved to rev it to 7 grand with a MP computer

I would say something else was the matter there. The only high RPM thing I have ever heard about 2.4's was lifters/head oiling. Some people rev those things way beyond 7k..