EssexBoyRacer

Being new to the cossie scene Im on a learning curve with whats what.

I've heard / read that the 2wd exhaust manifolds are better than the 4wd ones and a lot of ppl change their 4wd ones for 2wds? This true? What do you gain and does this mean you need a 2wd exhaust afterwards?

Ian2wdsaffcos

2wd is better for top-end power but probably not really noticeable until you get over 400bhp. 4wd is better for mid-range response & no you don't need to change the exhaust afterwards

Mike Rainbird

iTrader: (3)

Don't forget if you are changing a 4x4 engine to a 2wd manifold, you will need a damper bracket like this:

As the 4x4 head has no facility for a damper, as the reason they changed to a one piece design of the 4x4 item, was to eliminate the NVH issues with the 2wd item (which HAS to have a damper).

EssexBoyRacer

NVH?

foreigneRS

according to the usual myths surrounding cosworth stuff, a 4x4 one will give you less lag /earlier spool up than a 2wd one, but the 2wd one can flow more than a 4x4 one so can reach a higher power limit.

to me, that doesn't really follow. the one that flows the best, should also give the best response from the turbo, although the 4x4 one has the advantage of being much shorter so perhaps has a lower presure drop at the lower volume flow associated with relatively small turbo's (T3 and T3/4).

have you read this:

https://passionford.com/forum/viewtopic.php?t=87555

Ian2wdsaffcos

Noise Vibration Harshness

Mike Rainbird

iTrader: (3)

Noise, Vibration, Harshness . With the 4x4 manifold, it elminated this issue and so the 4x4 head doesn't have a mounting point for a damper...

foreigneRS

i might be needing one of those damper brackets mike. latest project appears to have a 4x4 headand 2wd fanimold. do you supply them?

Ian2wdsaffcos

Come on Mike, keep up!

Daveyraveygravy

Ian is right, i was speaking to stu at MSD yesterday about this! You wont notice until about 400bhp+ and he prefers to use the 4x4 manifold because you dont have to use the damper.

EssexBoyRacer

Cheers fellas! So not exactly a definate yes the 2wd is better than the 4wd its more down to tuners preference and how your building your car.

Mike Rainbird

iTrader: (3)

Nick,
Of course I do .

Steve,
No, is down to the power level you want. Upto 400bhp and the 4x4 one is best for ease of fitting / no NVH probs. Much above this, it does become a restriction, so would need replacing with 2wd.

EssexBoyRacer

But if I wanted a car that had more torque and quicker for 1/4s I would probably keep the 4wd manifold?

Mike Rainbird

iTrader: (3)

If you have under 400bhp you should stick with the 4x4 . If you have more, you should be changing to 2wd.

EssexBoyRacer

lol understood.

Mike Rainbird

iTrader: (3)

At last .