My rev limit is currently set at 7600. With a 5-speed tranny on the RS, I would like to be able to extend the upper limits of my powerband to 8500 rpm. I currently have HKS 272 cams and HKS cam gears installed, running off the stock HRA98-16G (9.8T) turbo and a fuel pump, run off the factory ECU with a custom tune.

I've spent a good part of the evening searching through hundreds of threads but have not been able to find out what components are required for me to be able to run 8500 rpm reliably.

ARP headstuds? Upgraded springs and retainers? Upgraded injectors?

 

So what turbo will you be using to justify this lofty rev limit?

 

You can install upgraded valve springs and retainers, but it will probably not be worth it with that stock turbo. Spend your $$ elsewhere on such goodies as a 10.5 hotside, ported manifold and an o2 housing. Then, throw some alky in the mix and turn up the boost! I rarely rev past 7k on the stock turbo, it's just not needed.

 

It would be a good amount of money for machining, but if you really want to go that high I would recommend it. Balance the cams, balance and knife the crank...and that will give you more stability in high rpm. Seems like finding a good machinist is the hard part. Getting everything blueprinted/balanced would definately be the way to go for reliability. IMHO

 

you will be runnin g a bigger turbo right, if not youre just wasting time and money.. there are some here who have just changed the cams and springs and havent blown up yet.. buts its unnessary wear..

 

I would be worried about rod bolts stretching as well. No doubt reving that high on the stock bottom end is def. going to be on borrowed time. Not to mention we don't even know how the oil pumps on these cars like those rpms.

 

Like others have said there is no point to run that high unless you're running a huge turbo that needs those high revs.. Stock turbo will not need it. Power will die out around 7000~rpm. Extending your revs will just make you slower.

 

Not always with alky and higher boost

 

No offense, but were not driving Hondas' here. No 8900rpm for us.

 

No offense, but guys with MR 6 speed could use the rpm's even on a stock turbo for 1/4 mile..I am going with springs and retainers so I dont have to shift to 5th and can spin 4th out a bit longer..

 

Actually, alcohol or higher octane fuel doesn't really change the powerband (just the power level), and higher boost with a stock turbo affects primarily just the midrange.

Many cars with stock turbos are fine with a rev limit of ~7800rpm, which is enough to accomodate typical optimum shift points. Once the optimum shift point has arrived, spinning it faster only makes it go slower.

 

PM ShaunSG..

He should be able to give you a quick, easy answer...

Kidding...

Unless your running a 35r or larger 8k+ really isnt necessary..

If that's your plan, the short, sweet answer would be to upgrade the valvetrain, and build the bottom end.

 

if you're into drag racing how about you spend all that extra internal money on the trany? i'm talking about getting your gear ratios adjusted. go get them to widen out your 4th so you can make the quarter mile without needing 5th. oh, and by buying the MR and using it to race is where you already messed up. lol

even if you did the high revving internal work, your turbo, like already stated, dies out around 7k rpm depending on which turbo you have. so, even if you have a 9 turbo, if you pass 7900 rpm you're powerband is already dropping. doing the internal work wont adjust your powerband to make power up there...our car relies on the turbo.

 

That would be nice but it's not possible or cost effective since there is no room for a taller 4th gear in the MR's case, and a new final drive can cost upwards of 1000 dollars and I am not sure it is even available for the MR..
And if you think using the MR for racing is where I messed up, why am I faster then 99% of all evo 8's with the same mods MR or not..
You don't need to explain to me how the evo turbo flows air over an rpm range, I am fully aware of that.And I am fully aware of what running high rpm's on the stock turbo will do..Just because the curve is not going up, does not mean it is not there..
BTW all the extra internals money costs about 250 dollars..I'll look into getting my "gears adjusted"

 

No, it means the rate of acceleration is on the decline.

Regardless of whether one has a 5 or 6 spd, a shift point calculator reveals that point whereby spinning it faster means going slower - for each gear change. If one has a copy of his dyno sheet and knows his gear ratios, it takes about 10 minutes to get the facts.