Fast4525

A few months have passed since the introduction of the Vitesse MAF conversion kit for the 964 3.6L. How many are now in circulation? Any new dyno charts? User feedback? John?

http://www.vitesseracing.com/html/91..._air_flow.html

deoxford

I love mine still,
Got it on the track a few times now and I have been very pleased with the upgrade

Ritter v4.0

I can't give you a good indication based on my data.

I tested mine on an engine that is down 25hp over Derek's car (but up 25hp over stock). My leak down numbers post dyno suggest a new top-end is in order.

Fast4525

Not sure what you are saying. Do you have the Vitesse kit? Did it pick up 25hp on your car?

Ritter v4.0

Yes. Derek and I have similar set ups (exhaust etc.) but he yielded +25hp more than I got- his on a recent top end rebuilt motor.

I thought my engine was pretty strong but as it turns out it isn't, so the combination of Vitesse MAF and bypasses has me about +25 over stock but still -25 less than Derek. I have to remedy that ( the weak motor that is).

Sire

Today i was invited by Beek Racing in Holland, they knew about mine MAF and helped me with the last bit off tuning the MAF. So i with there help we achieved 293 HP.

NineMeister

Which is probably as good as it gets because you will be at the limit of flow of the standard fuel injectors. Still a decent result though for a relatively easy conversion.

MitchB

So do you think there is more HP on the table by going to larger injectors?

I asked John @ Vitesse about this very issue. I have a Vitesse MAF, but haven't installed it as the chip needs a re-flash. I asked because I would have bought larger injectors to optimize the MAF since it needed a re-flash anyway...
He said - "not for a stock motor..."

boxsey911

Colin, speaking of easy conversions what's your experience of the increases obtained with your simple RR re-map service? I know it will be dependent on the state of the engine but do you think an ECU that's not been touched for 18 years will benefit from a tune up? Mine's standard apart from a cup pipe BTW.

NineMeister

In our experience with the Motec conversions, a perfect engine would always benefit from larger injectors. However without understanding the limitations of the stock Motronic system (with or without MAF) I could not be sure that you would get the same result from an injector change, but my guess is that it would benefit to a lesser degree. It's up to John to decide if this is a path worth investigating in spite of the limited commercial value of the end result.

NineMeister

We get 290hp from a typical stock 964 and 300hp from a 964RS or Cup car.

boxsey911

Sounds great. That'll go on my list after the suspension upgrade

Ritter v4.0

Colin, can you amplify this statement about larger injectors irrespective of the Motec/Motronic argument? Are you saying that the duty cycle of the stock injectors on a stock 3.6 motor can be max'd through tuning?

NineMeister

In my experience with Motec on many 964 & 964RS engines, the standard injectors running at standard fuel pressure will not supply sufficient fuel to achieve the maximum potential power on the dyno. As far as I know, the 964 Motronic reverts to batch fire mode (continuous) as a compensation for this deficiency. To quantify this, on the very first Motec conversion we thought we were doing well to get 305-310hp from the RS we were working on until I realised we were running close to 100% duty cycle. After fitting a set of 400c injectors we achieved 324hp on the same dyno under the same conditions. End of story as far as I am concerned.

Ritter v4.0

Cheers.