924Board.org

[flosho]

What would I need to do to allow my car to spin up to 7000 rpms? This xmas I'm gonna get a new cam for my car.. probably a integral stage 2 cam, and I want to run my car to about 7k... Well.. I want to be "able" to. Depends how much power I can even get up that high with the stock turbo and manifold. I want to plan ahead though.

Is the stage 2 a direct drop in, or do I have to modify the lifters or valve springs..

Do I have to replace/source some stiffer valve springs for the higher RPMs?(to be able to spin 7k)?

I know the k26 is probably close to, if not out of its efficency range in the 7k range but thats what datalogging is for and tuning..


Any input is appreciated.
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[This Space For Rent]

[morghen]

hmm...i think you are limited to 6500 RPM form the ignition system.
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Supercharger and EFI kits
https://www.the924.com

[John Brown]

The poorly documented rev limit I THINK is in the fuel pump relay. Use a different relay or bypass. Really don't recommend a complete bypass as it has severe safety implications not to mention loss of overboost protection. Read and understand the fuel pump circuit.

The K26 is capable of supplying all the air needed.

The motor will spin to 7k. How much power it makes over, say, 6.5k is a different matter.

If you find valve springs for this motor let me know. However, I have spoken to folks who have spun the stock springs reliably to 8k, but don't know what cam they were using.
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John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

[924RACR]

I've had no issues revving occasionally to 7k on stock springs, stock cam. I don't make a practice out of it since I want durability and I lose torque up there anyway. I only really do it if I'm trying to make a pass and need to skip a shift. Probably will be doing more of that next year! LOL

I would recommend all new springs (EBS Racing), new valves would be a good idea, check or replace guides and retainers (maybe use titanium retainers). All that valvetrain stuff. HTH
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[P924]

I've had a problem once, i couldn't let go of the gas, so the car went al the way trough the red zone at 7.5-8k RPM. And the car still runs, happened once and it won't happen again
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924 1981
911T 2.2

[flosho]

Well I only shift at 6k now.. and I've hit the rev limiter on a few occasions, not fun...

If I rebuild my spare head.. I'll go with new springs and valves and stuff..

But what if I want to do that on my head I have on the car now.. Just drop in a stage 2 cam. The head I have on there now is brand new.. new valves, guides, springs, everything.

How do you remove the rev limiter? *edit* n/m so I need a different fuel pump relay... I've never heard of anyone changing their fuel pump relay, only bypassing it for a switch or something similar..
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[This Space For Rent]

[Rasta Monsta]

You should ask the vendor about followers. I have always believed that they were required with a new cam, but have seen little mention of it here.

rasta
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Smoothie]

US 931s got the fp relay with built-in rev limiter to cut fuel so's to not wreck the catalytic converter. Euro (RoW) 931s got a rev limiting distributor rotor that cuts spark and allows unburnt fuel to flow through the exhaust. -There's a variety of rev limiting rotors available with different limits as they were used on 911s and 914s also, so there may be one in the range you're looking for, but I don't know off the top of my head. I popped the cover off my rev limiting fp relay once for a look inside and found a component that's adjustable by screwdriver. In the discussion here - http://www.924board.org/viewtopic.php?t=10360&start=11 , we were guessing that adjustment was for the rev limit. (The pics are gone now, but the adjuster is obvious once the cover's popped off.) -So just maybe, you can increase the limit of your existing relay. I don't know of anyone who's tried it or which way to turn and how much, so it would be experimental, but if that is actually the rev limit adjustment I'd think something could be done through trial and error, on an empty road, with seatbelt fastened tight. Remember to mark the adjustments' current position before altering it.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[emoore924]

Last time I heard about someone revving a 924 to 7k or more it was ryoji at Summit Point. Bottom end suddenly let go with a bang and put a rod through the side of the block. Moral of the story: be sure you have TWO more things up to snuff before revving that high -- 1) the bottom end, which is otherwise bullet proof, and 2) your fire suppression system.

[Smoothie]

Here're 3 versions of rev-limiting rotor (7100, 7300 and 6500 rpm) in case you're still interested, and don't have a good cat to worry about (-and I believe unburnt fuel is also bad for o2 sensors) -
http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search.cgi?command=show_part_page&please_wait=N&make=POR&model=911E&section=ELignt&page=1&bookmark=6&part_number=911-602-928-00-M14
Proceed at your own risk..
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[flosho]

So the 7300 rpm rotor and a 924 n/a (433) fuel pump relay and I'm good up to 7k...


Whether or not I make any useful power is still to be determined.
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[This Space For Rent]

[Chrenan]

Will the oil pump see some cavitation at those RPMs?
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1987 951 - M193 Version for Japan

[Smoothie]

I should add that although I'm pretty sure, I'm only going by partially educated guess that the 911 rotor will fit the 924/931 distributor. What you need is for someone with both a 924 and 911 (like macBdog? nudge nudge) to try a swap to see for sure if they're interchangable.

I'd be willing to guess the $31.66, #931-602-904-00 rotor here is the RoW 931 rev-limiting rotor -
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?&command=DWsearch&description=93160290
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[jazz guy]

Smoothie, I'm pretty sure your advice about the adjuster in the fp relay is correct. I have never played with it, but a friend of mine with an '82 931 talked about adjusting his. He was able to raise the cutoff by turning the screw. IIRC he said to be careful, as the adjuster is quite sensitive and a very small movement made a significant change to the cutoff rpm.

I'm going to look into it on my 931 because hitting the limit with full throttle and the boost turned up is like running into a brick wall.

[Lizard]

I would want to replace the springs with at a minimum stock valve springs if not alittle more, valve float would not be good
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3 928s,