So what are you Guys reving your 2.5L's to?

[LynX853]

I'm talking on a built block with no ballance shafts, ported head with cam and supporting valve springs ect.

What should I wind it up to? the holset seems to love riding the rpms' seems to make power up to red line with my setup... so how far past redline should I go?

setup: Fuel - 40's injectors, high flow rail, 255 pump, afpr. Block- fwdp built 2.5 bored 30 over, forged internals and arp everything. Turbo - holset hy-35 with 10cm exhaust side and custom oversized wg puck. Exhaust - ported and coated tbi header. 3'' exhaust. the rest: Large fmic 4'' intake, ported 1 piece (I know its my bottle neck but I have a custom 2 piece on the way)
LWP - 782R head, t2 cam
trans - cliff built a413 RMVB and a high stall
shelgame cal

I think thats about it.

[Gaboon]

Each set up is different.

Put it on a dyno and see where yours likes to run. It's the only way.

[GLHNSLHT2]

My rev limiter is set at 7200rpms, I've wacked it 2 or 3 times now on accident.

[LynX853]

Each set up is different.

Put it on a dyno and see where yours likes to run. It's the only way.

hmm... I guess another good question would be when do rods start flying out of the block

[JuXsA]

A few friends of mine were reving their 2.5's to 7500 rpms. I think ozspeed was going to 8k on his 16v 2.5L

[Juggy]

a good rule of thumb for the rev limiter is approx 500rpm after the engine makes max HP

[mopar-tech]

I'm talking on a built block with no ballance shafts, ported head with cam and supporting valve springs ect.

What should I wind it up to?

If you hit 6000 RPM you are wasting your motor for no reason.

The 2.5 is a stroker motor, its all done by 5500.

[LynX853]

If you hit 6000 RPM you are wasting your motor for no reason.

The 2.5 is a stroker motor, its all done by 5500.

I was just reading the 2.2 or 2.5 thread, and it seems like a lot of people are going above 6k with them on a heavy modified setup. I dont consider my car a 'light' setup, and I'm finally taking it to the track this weekend. Ill have to see how she feels with the DR's on at MIR

[mopar-tech]

I was just reading the 2.2 or 2.5 thread, and it seems like a lot of people are going above 6k with them on a heavy modified setup.

Going "above" doesn't mean your going fast.

The Reliant ran quickest shifting at 5000 rpm.

Proof is always in the timeslip.

[GLHNSLHT2]

Proof is always in the timeslip.

True. But that doesn't mean every 2.5 and every track is the same. When I shoved a 2.5 shortblock under my 87 T2 top end I thought well Gary and Gus shift at 5grand that's where I'm gonna shift. Heh, car went slower than it felt. So I started increasing my shift points. With a stock 87 T2 top end and intercooler my 2.5 liked 5700rpms. Putting a cummins in the nose and having smooth 2.5" piping raised that to 6grand if I wanted but still ran the same time if I shifted anywhere between 5700 and 6grand. A S60 turbo and 3" swingvalve would bump the 6250 rev limiter. So I jacked it to 7200 just to be sure I wouldn't hit it even though I was still shifting around 6100 or so. With the new ported head, big plenum on a heavily ported lower 2 piece, and my JRB header the car feels quickest shifting somewhere above 6500 but I haven't been to the track to test the new setup yet and it get's there so fast on the street I don't have time to really watch the tach. That's why I've bumped the 7200rpm rev limiter a couple times. Mash the throttle half way thorugh 1st or 2nd and I've whacked the limiter just as I push the clutch in to shift. Even if I'm making power up there (need to get it on the dyno) I don't really want to shift it too much higher with the insane piston speeds it's got to be turning.

[mopar-tech]

With the new ported head, big plenum on a heavily ported lower 2 piece, and my JRB header the car feels quickest shifting somewhere above 6500 but I haven't been to the track to test the new setup yet and it get's there so fast on the street I don't have time to really watch the tach.

Feeling quick and actually going quick are two different things.

Bore and stroke are fixed on a 2.5, this will limit peak power and torque more than anything.

[LynX853]

Feeling quick and actually going quick are two different things.

Bore and stroke are fixed on a 2.5, this will limit peak power and torque more than anything.

bore and stroke are fixed on every motor, unless you can come up with a way to have adjustable rod ratio.

I think it comes down to the cam, springs, headflow, intake design and turbo as far as power to redline and beyond goes. I can Feel that my car is making a lot more power up top now, and dosn't seem like it just dogs anymore in upper rpm. the powerband definetly has moved up. I just want to know how much. whats the setup on the reliant?

[Directconnection]

I've argued the 2.5 rpm limitations for years....

I am sure in some rare instances, a properly built 2.5 could make peak power a bit above 6,000 rpms, but.....

Gary, how many 2.5's have you and I witnessed on the dyno?

[Directconnection]

bore and stroke are fixed on every motor, unless you can come up with a way to have adjustable rod ratio.

I think we know he understands this. What he's probably hinting to is that us 2.5 owners are stuck with the limited rotating geometries due to the 2.2's same deck height, rod length, and limitation of the ring pack of the 2.5 as the pin is moved up and the rings too far at the top of the pistons. Nothing else we can do to help w/out having a shorter rod which in turn, increases sideloading due to poor rod ratio.

But alas! There is..... if you really want to prove people wrong. Re-sleeve for larger bores, or build a deck shim of sorts (saw someone do this on an LS2 in a magazine to increase deck height) like Hondas use. And/or do what we do at work quite often with just about every high output stroker engine we build. Custom pistons with the pin bore into the oil control ringlands... but they use a *rail* to support them where the pin bore bores through.

[mopar-tech]

I think it comes down to the cam, springs, headflow, intake design and turbo as far as power to redline and beyond goes.

The Reliant had one of the best SOHC setups going bar none.

You won't see many SOHC motors with a 1 to 1 intake/exhaust pressure ratio, the Reliant had it.

If you wish to wind a stroker motor far past what its nature hp peak is, then by all means go for it.

[mopar-tech]

Gary, how many 2.5's have you and I witnessed on the dyno?

Hundreds including Brian Slowes 2.5 16V which made 500 ft/lbs of peak torque at a rediculous 2600 rpm.

[mopar-tech]

What he's probably hinting to is that us 2.5 owners are stuck with the limited rotating geometries due to the 2.2's same deck height, rod length, and limitation of the ring pack of the 2.5 as the pin is moved up and the rings too far at the top of the pistons.

Which is why on the last motor moved to a 2.2 displacement.

[BF/STOCKER SPIRIT]

Listen to man!!!!!!!!! Hey gary nice to meet you,

jimmy

[GLHNSLHT2]

Feeling quick and actually going quick are two different things.

Once again true, that's why I said I hadn't been to the track yet to test what my butt is feeling so you can take it with a little bit of a grain of salt. But there's no way I'll be shifting down at 5000rpms. The motor just starts to really sing at 3500. It's limiting factory right now is the S60 turbo. Definately needs a stage 2 or maybe even a stage 3 exhaust wheel. But it is fun to be able to spool it line a VNT car, starts building boost at 1300rpms The torque curve and throttle response feels like a big n/a motor.

bore and stroke are fixed on every motor, unless you can come up with a way to have adjustable rod ratio.

I think it comes down to the cam, springs, headflow, intake design and turbo as far as power to redline and beyond goes. I can Feel that my car is making a lot more power up top now, and dosn't seem like it just dogs anymore in upper rpm. the powerband definetly has moved up. I just want to know how much. whats the setup on the reliant?

You're on the right track LynX, there's a couple things out there now that really help the 8v rev further than it did 8-9 years ago. Hell even 3-4 years ago.

[Directconnection]

You're on the right track LynX, there's a couple things out there now that really help the 8v rev further than it did 8-9 years ago. Hell even 3-4 years ago.

Yes.... solid lifter cam. No high performance engines run hydraulic lifters.