Manifolds

[itsallyellow]

Does anyone know the ideal dimensions for an AJP manifold? Length of primarys, size of them etc etc.

Thanks

Mike

[Gas Man]

Hi Mike

I did a bit of Google searching and came up with this.

http://www.wallaceracing.com/header_length.php

Hope it helps.

Steve

[trackcar]

At the moment there isn't any one manifold design out there that seems to outperform any other, only the small bore 4.2 is one to avoid from my testing, all the others give results about what you would expect, so they're all either good enough or they're all poor, but by the same degree.

So far I have tested the 2 tvr manifolds in small and large bore, some aftermarket cerbera fit manifolds, some 4 into 1 manifolds that bear no relation to anything on cerberas, and the tuscan race manifolds and they all give about 400hp and 360lb.ft on a std remapped short induction car. I know clive at V8Enhancements is working on some other designs for his own 4.2 AJP griffith and we hope to make something which does work better, but then again they might just give the same as all the other manifolds yet lol, we just don't know till they're on the car.

If you want something truly esoteric get in tough with BTB and ask about their cerbera manifolds .. at a cool 3500 pounds they certainly get the prize for most expensive

[itsallyellow]

Joo i will be getting a set made as the exhaust will be going a completly different route than normal.

So would i be correct in saying that no one really knows what is best for the AJP?

Mike

[trackcar]

Well its either that Mike or whatever you try just seems to give the same result ...

[HarryW]

itsallyellow said:

Joo i will be getting a set made as the exhaust will be going a completly different route than normal.

So would i be correct in saying that no one really knows what is best for the AJP?

Mike

I think any experienced/decent exhaust designer should be able to crack it tbh. Just treat it as 2 x 4 pot BDA's . The compromise will be packaging, like all TVR's getting the longest straight run out of the heads is the most difficult to achieve before you put the first bend in and where most gains will be felt/or lost imho.
Anything with ~1.625" to ~1.825" primaries and at least 30" long merged odd and even and similar lengths secondaries with long merges again. All merges to be at least 60degrees if not shallower. I can't be arsed to look now but I did a sketch design of the 'perfect' complete exhaust (manifolds to tips) for my Cerb but couldn't package it to fit the car, shame really as I felt there was say 20hp in it.

[itsallyellow]

Well packaging shouldnt be to much of an issue as the body will be cut to fit. The only thing that can get in the way is the pedal box.

Mike

[trackcar]

Whats your budget Mike .. email me if you want.

[markh1]

I have ACT manifolds, and they gave a noticeable increase in torque without a remap so would be interesting to see what they are like after a remap.

[Gas Man]

itsallyellow said:

Well packaging shouldnt be to much of an issue as the body will be cut to fit. The only thing that can get in the way is the pedal box.

Mike

Mike the most efficient header is a dead straight one like on dragsters.
The length and diameter being calculated in the normal way.
Our manifolds have the collector where the dragsters exits to the outside world!
So if you can keep them as straight as possible before you join together you should get the most efficient system. In a race car this could be very interesting!

All theory of course!