pp13bnos

iTrader: (1)

This was when the motor was in my 90 with the 51mm webber.

pp13bnos

iTrader: (1)

This shows the entire engine bay of the 90 again. The air cleaner was WAY to small to realy breath. Had to make an air box. Notice the power steering?

peejay

Hey! I resemble that remark. (Gotta do SOMETHING with junk housings...)

Logically, given the same port size, a 12A should make its power higher up than a 13B since it'd have to rev faster to move the same amount of air. I recall an old article about the GTU effort in the early 80's, they restricted RPM to 10,500 "to save the plain bearings" but "some other teams were going as much as 1500rpm over that". I'm sure there is other anecdotal evidence to substantiate...

THC

My son met a fellow at AutoZone who was driving a carburated 13b and claimed 14k rpm capability. He opened the hood, started the engine and my son said he saw the tach pegged and held there for five or ten seconds. This fellow claimed the engine really took off at 7k. There was a headder system that was quit different and the carb was on the side of the engine. The fellow said he had it built somewhere in Tenn. I believe, many special components.

So maybe they are out there?? Who knows!!

pp13bnos

iTrader: (1)

I gotta run to work...but one more before i go.

RICE RACING

To do all of this efficiently I.E. make peak power or 80% of peak at these elevated revs (say 12k) would require very short intake section, very large square intake profiles (like used by many 12A runners here and in the US in the mid 80's) and very large, and short (collected) tunned exhaust pipes.

There are many mechanical limits on 7 pinned rotors in the early engines which require snap rings to be installed as the load on the rotor gears is virtually exponential once 7000rpm is exceeded, then there is rotating mass issues requiring added clearance of rotor sides and faces. The list is endless.

It is very very hard to lift the range of usable power above 10500rpm in a 13B regardless of porting configuration, To give you some indication of what I am talking about in real numbers lets look at this.

If you could maintain torque at an acceptable level as you can in the region of 5 to 8k in a "normal" peripheral port but apply it to the magical 11k range then you will be making around 400bhp instead of the 300 you would normaly make @ 8500 with a weber and tolerable exhaust. Apply this to the magical figures we are hearing say 13k then you would be making 460bhp !!!

One of the best 13B's I have seen made 380bhp @ 9500rpm with realy well made Induction system and race exhaust, this @ 13k would be around 520bhp !

My point is that people may be reving their engines to stupid rpm levels, anyone can, but what spread of power they are making and if it is more than what they have @ 10000rpm is what some people are finding hard to swallow.

RICE RACING

Hey Steve, my performance bench mark is the Ferrari F40 (my dream car) and I designed my RX7 to match this car as best I could with my measly budget and basic skills !

It has 478bhp (engine) and weighs 1100kg does 320kph top speed....I have an article here from one racing at Calder Park in 1988 street meet !!!!

It did 12.23 seconds @ 127.9mph

My car is geared the same has the same top speed, Makes 540bhp, weight 1070kg, in the in gear acceleration figures I have I out do it (F40) by a margin of around 10% for all the accel figures up to 220kph (so aero drag is similar), I even have a power curve of an F40 engine and my average power across my gear ratios (8400rpm shift point) is a fair bit higher too.

I estimate I would be able to do 130mph trap speed, based on all the other data in street trim, what do you recon ?

I am getting a gee up just thinking about it..... I think I will give it a shot just for fun !

AJC13B

I will probably be racing at Supernats on street tyres and pump fuel just to see what happens. Might put the slicks on for a pass and see if I can get a 10 on pump fuel and maybe 19psi? I think a mid 11 on street tyres is attainable since I did 11.8 with a dud boost controller and a dud box! lol

You should come up and race that weekend! Bring slicks and street tyres though, because if you run a 10 and the car isn't ANDRA tech inspected, you won't be allowed to race again! You also have to have an ANDRA license for quicker than 11.99 passes...actually I think it would be easier for you to run at Heathcote where you don't have to worry about any of that ANDRA stuff

cmartinp28

so can someone tell me, what really is the point of revving beyond 10,000 rpm? doesnt the power plateau? just curious cuz of all this talk about 14,000rpm's and that redicuouls 18,000rpm

peejay

Some people feel that RPM = power even when the engine stops working and just makes noise!

Rotortuner

Ya this is true, and just cus your motor "keeps going" doesent meen it acutaly making pwr like it was doen at say 9k.

CJG

diabolical1

iTrader: (3)

daaamn ... can't believe this thread is still alive and kicking ...

you guys keep up this 14,000 RPM-stuff and someone's gonna put an eye out ...

Rotortuner

Yeah i know this has more views and post than anything else almost. But it gives us something interesting to talk about.

CJG

diabolical1

iTrader: (3)

yeah ... it sure does.

Aico

I agree to.

Rotortuner

So has any one else though had custom headers made? adn how have you liked it?

CJG