k, ive install some new things in my engine. its not running yet, but it will be soon.

specs in the head are: ss valves, crower springs, crower ti retainers, pt lifters and rockers. and crane 14 turbo cams. wondering how high i can rev safely. also have eagle long rods, je pistons. will be running the msns setup.

Part of me wants to say that, after the engine is broken in, you could take it to the dyno and see where the power starts to drop off. Considering MSnS will maintain your AFRs for you. Could this be a game plan of sorts? No point in winding her up beyond where she's going to do any good, right? :shrug

Originally posted by DR1665
Part of me wants to say that,

and the other part?? finish a thought there buddy?!?!?

Originally posted by DR1665
No point in winding her up beyond where she's going to do any good, right?

Unless youre doing a top speed run, or want to program your rev limiter.

I think the number of people on this board who have safely exceeded the factory rev limiter could be counted on one hand. With a mitten on. Not saying don't do it, but maybe just call Hahn / Ayala / Cox / Howell instead.

Originally posted by thedawg

Originally posted by DR1665 No point in winding her up beyond where she's going to do any good, right?

Unless youre doing a top speed run, or want to program your rev limiter.

Well, I was speaking along the lines of making a dyno pull and seeing where the power band begins to drop off. I don't see why you would want to hold out a gear much beyond peak power even if you were making a top speed run.

Originally posted by thedawg
I think the number of people on this board who have safely exceeded the factory rev limiter could be counted on one hand. With a mitten on. Not saying don't do it, but maybe just call Hahn / Ayala / Cox / Howell instead.

Does winding her out to 7800rpm where you get ignition cut with the AFX/R count? :P


Yeah. Yeah. Go ahead and say some shit about ring gaps again. Blah blah blah. :rolleyes New block is balanced and professionally assembled. I'm going to see how high she needs to spin to make the most power NA when I take her to the dyno in May (assuming I get my fucking MS sometime before the end of the month).

Brian's right. Dyno it and see where it falls off, that's the best way to find out.

The motor itself should be able to spin some high RPM's (~8k), I wouldn't do that because you want the motor to last, right? No offense, but the crane 14 cams kinda suck. Don't get me wrong, they're better than stock no matter how you look at it, and you'll be happy with them. I had them and I'd hit the factory rev limiter not paying attention because it was pulling strong still and sounded good.

You'll want to find where the HP curve drops and figure your RPM drop from each gear. You want to shift to optimize HP. If you wait too long, then you're at a point that has less HP than if you shifted to the next gear.

I'd say shift at around 7200~7400 and you'll be just fine, then set your rev limiter 200-300 above that. I shift my cougar at 6200-6300 and set the rev limiter at 6600.

thing is . i dont think i have a drop point in my car until late 8k's. remember, im spooling a s25g. i think it would take about 9k's to totally turn the turbo as fast as it can go.

with those longer rods, the rod ratios are a little better so im sure 9k isnt completely out of the question. 9K, 25g..25psi...neon gearset, you'll be flyin. like brian said though, its pointless if you're not making power up there.

I've made sure to have everything built to be a high-revving motor; bottom end is balanced completely, and the head is all built up as well. I'm not going to try anything drastic until such time as I have her properly tuned. MSnS + Zt-2 will give me the safety in terms of fuel and timing, so I'll just need a couple dyno pulls to figure out how high I need to go to make the most power. Once I know where peak power occurs, I'll have the MSnS start to pull timing shortly after that point so I'll be able to feel her drop off before I hit the rev limiter. Isn't that what they call a "soft touch" rev limit?

That is going to be one sweet day, imo. :7

I've never heard of anyone busting our crank, thats your weakest link imo. I would be scared to go above 8.5k. Doesnt the afx ecu raise the rev limit to like 83?



Nick
97RS

Originally posted by Collente
I've never heard of anyone busting our crank, thats your weakest link imo. I would be scared to go above 8.5k. Doesnt the afx ecu raise the rev limit to like 83?

af/x raises it to 7800. the problem with redlining that high is excessive wear on the outsides of the pistons because piston speed at 9k rpm's is incredible. and if you were using the stock rod length, the excessive rod angles would push the piston close to the cylinder wall. with the longer rods piston speed is slower at different points and there is less stress on the piston skirts. you might have oil control problems as well, but i doubt it. if anything, worst case scenario...a bent rod, depends on how much power you're making though and what rods you have.