Guys,

I'm looking at a couple different 3rd Gen cars to buy. But I have a few (seemingly strange) questions:


1) What is the maximum speed (mph) for 3rd gear at redline (7,500 rpm?)?

2) At about what rpm does the 2nd turbo start making boost at full throttle?

3) Let's say you were racing with a stock engine ... what rpm would you feel comfortable revving the engine to, before shifting to the next gear? Redline? Over redline? Less than redline? And I don't mean on a one-time basis, I mean continuously, as in racing conditions. What rpm would you feel comfortable shifting at that would provide maximum power and yet not damage the engine. Sure redline may be the obvious answer, but I want to hear it from guys who actually will know.

4) Do certain apex seals allow an engine to rev past stock redline? I heard (a long time ago) from a guy who raced 1st gen cars, that the rpm redline is set based on primarily the limits of the apex seals. That's what I heard, don't know if its true. So is it true that 'better' apex seal may let the engine rev higher with no damage?



I realize these may be stupid questions to some of you, but if I don't know the answers, all I can do is ask. If you feel the need to ridicule me, I'd rather you not reply.

Lastly, it would help me a lot if you guys could answer all 4 questions like I have asked. Thanks.

- JyRO

 

1) past 90mph...I never looked at the speedo, I consider redline to be 8k
2) 4500rpm
3) 8k
4)I don't believe that statement

 

I watched the speedometer with someone else driving, redline came at about 100 mph in 3rd.

 

Most of the answers to your questions can be found with a simple search. So please try to use that function next time. But I'll try to help you out.

1) That depends on the diameter of your tire. Nominally, 7500rpm in 3rd is gonna be about 98mph. Of course, redline isn't really at 7500, its 8000 (which will take you to about 103mph).

2) Transition happens at appx 4500rpm.

3) Again, that depends. What kind of racing are you doing? Drag, autocross, track, etc? For drag, you want to find your optimum shift points. This is the point where the torque available at the rear wheels in the next gear exceeds the gear you're currently in. Search for more info on this (Jimlab has some great posts about this). For a stock engine, this will be at redline, although most people shift just prior to redline in first gear to avoid over-revving. For track tracing, most people shortshift slightly in all gears (7250-7500), for the same reason.

4) While true that some apex seals/springs may be less prone to chatter, this is not the only mod you'll need to increase the redline much above 8k. There's a lot more that goes into it. Plus, theres absolutely NO reason to increase the redline in a stock ported motor, as the engine is essentially out of breath at 7500-8k rpm. Realistically, the only people that run much higher revs are those with massively ported engines.

Again, SEARCH the forums for more info about these (they have been discussed quite a bit).

-Rob

 

dubulup - Great, thanks for the info. As for the #4, like I said, its only what I heard. Not knowing in detail about how the apex seal work, I couldn't know if it true or not.

- JyRO

 

Thanks for the input. 1) I am considering a stock size tire.

2) 4,500 rpm works for me.

3) I hesitate to mention what I will be doing with the car. Regardless I don't think I'll be doing much more than 90 mph or so. I understand the dynamics of shifting. I roadraced motorcycles in WERA in the 90's (#701).

4) I had to ask the question that way to get the answer I was looking for. But it seems as I will not need to rev past 8,000 ever, probably less than 7,500 rpm most of the time. I will need to know (maybe a later post?) more about seals so later on I can buy the right kind. The kind that will take a lot of abuse/heat, and is good for up to 350 h.p. or so. Thanks again.

- JyRO

 

I just ran mine two days ago and hit close to 105 or so redlining (~8200rpm).

Craig

P.S. Who else thinks 3rd and 4th gears are the best of the bunch???

 

I That is if you hadn't busted a 3rd gear syncro chasing a porsche. +1 for h shifting untill next week.

 

Ditto, just pushed around 105-110 at the very top of third about 30min ago. I seem to pull the hardest in 2nd and 3rd gears. Don't really feel it too much in 4th but then again thats getting up there in speed so I'm prolly paying more attention to the road then the car.

 

2nd is sick!!

my 5th is how you describe your 4th, so you car is probably just slow

on crisp cold mornings I can see up to 15psi at 4k in fifth!

 

Hey guys, I was just able to check this topic again. Thanks for the good info. I may wind up purchasing one of the 3 I'm looking at. Should wind up having fun with it. I doubt it will ever see much road use though, at least not legally .