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.

[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

[GLHNSLHT2]

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

[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.

[Ondonti]

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

The Reliant ran quickest shifting at 5000 rpm.

Proof is always in the timeslip.

your motor was built to make power at the rpms you were using.

Bore and stroke don't prevent high rpm power, they just won't be optimum. There are a crapload of motors with small bores and large strokes that still make high rpm power when modified to do so.

Trying to make enough torque to get all the HP done with by 5000 rpms leads to engine failures that cut the reliants life short.


my policy, rev as far as you can without requiring excessive upgrades (if budget allows). For 8 valves, lifter collapse is what would stop me. I wouldn't want solids. That seems to happen before a decent set of 2.5 rods/bolts would ever let go.

With a fat budget, other things are always possible. You sticking with an 8 valve when "other" setups would be more efficient shows that you don't need to have the "best" platform to have good results.

Proper heads, cams, intake manifold, exhaust manifold, budget would be the limit on rpms.
And on a 4 cylinder I think its a lot cheaper to rev higher then to try to make ridiculous motor shredding torque/cylinder pressures on a small displacement motor in order to get the low RPM hp required to make a good 1/4 pass.

Id get some 4 bolt mains to go around with a high reving 2.5. Heck, Simon is reving his 2.5 way above 7000 and so was Corby with just an 8 valve. Corby backed up his rpm choices with #'s at the track. I don't think his powerband started until after 5500 rpms, which goes against what you said and he backed it up in a vehicle 1000 pounds heavier then yours, 4400 feet higher, with a barn door drag coefficient.

[moparzrule]

Bore and stroke don't prevent high rpm power

Thats true, it's certainly not the only factor but it does have some affect. Simon's 16v 2.5 may be spinning 7000 RPM, but the same top end on a 2.2 would probably be spinning 8000+ with ease.

Trying to make enough torque to get all the HP done with by 5000 rpms leads to engine failures that cut the reliants life short.

Lower revving engines tend to last longer, whats your reasoning for this statement?

[Directconnection]

your motor was built to make power at the rpms you were using.

Of course, and that's why he switched to a 2.2.

Trying to make enough torque to get all the HP done with by 5000 rpms leads to engine failures that cut the reliants life short.

Wrong. It was a 2.2 when it pooped the bed. I also saw it on the dyno a month prior when it accidently went to 8k. Guess what? It didn't make peak power at 8k, or even 7k. He had Menegan's best on the car, too.... since then, manifolding could be improved upon as he was using ported pieces, but not like they'd uncork 8k rpm potential.

Corby backed up his rpm choices with #'s at the track. I don't think his powerband started until after 5500 rpms, which goes against what you said.

I would bet the farm that "I don't think his powerband started until after 5500 rpms" has soley to do with the turbo only. I highly doubt in NA form that there is nobody home at 5,400 rpms. It's all about the boost response, right?

Not arguing with what you wrote, brent.... but I don't know what is so hard for everyone to understand: You add stroke, you add a boatload of torque and a decent amount of HP at a lesser rpm.

Not saying a properly built 2.5 can't make peak power at 6,500 rpms ... but....

Back to my post on page #1: how many 2.5's and 2.2's have you seen make peak power UNDER 6,000 rpms Gary? How many made peak #s above?

[mopar-tech]

your motor was built to make power at the rpms you were using.

No, my 2.5 was built to make power period. Best head, best turbo, best air to air intercooler, etc.

The 88 TBI cam was in there because in track testing it worked best compared the Super 60 cam for aurgments sake. I even did a cam swap at the track to test A-> B results.

The car had to be molded around the engine to take maximum advantage of what it did best.

[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.

[black86glhs]

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

True, but it depends on the definition of "high performance engine." Not being a wise guy Steve, just that many people say and believe different things.

[Directconnection]

True, but it depends on the definition of "high performance engine." Not being a wise guy Steve, just that many people say and believe different things.

OK, change the words "high performance" to "Race"