3.0 MFI

Hi guys'
Weather is nice so it's time to get back to the 72 Targa project.
I found a 79' SC donor car for my project. I want to build a 3.0 MFI motor. I have a 2.4 MFI parts motor. I want to put the MFI,E cams and the exhaust from the 2.4 on the 3.0 motor. Sort of a milder 3.0 RS.
What I'm wondering about is matching the MFI pump to the 3.0
It seems to me that the cam in the injection pump needs to match the cams in the motor. No problem. I've got that. So correct me if I'm wrong but can't I then match the displacement with the fuel enrichment mixture?
I know I'll have to replace the pistons with some that would match the cams + MFI. I'll also probably have to get custom throttle bodies made if I can't adapt the 2.4 bodies to the 3.0 heads.
I really like the throttle response of my 72' MFI coupe so I hope this might work . I figure my chances of getting 3.0 RS MFI pump parts are slim to none. If I can't make this work I might go EFI. I know it's silly but I think the MFI motors look so cool.
Thanks in advance,
Bobby

Bobby,

I don't think it is quite as simple as your cam matching & enrichment theory. What I think you should do is contact Andial and discuss what changes and adjustments are needed to apply their 3.0 conversion piston sets for MFI to a 2.4S/2.7RS engine. If you can't get an answer, or still have any doubt, contact Pacific Fuel Injection or H & R Fuel Injection LTD. to see if they can recalibrate your pump for a 3.0 application. I suspect they will not have any experience with using 'E' cams, and that 'S' or GE-60 are the only realistic choices.

The simple fact is that as displacement rises, for the 'S' cams, the torque curve gets lower and broader. The 'hump' of the RS 2.7 engine torque curve begins where a 2.4E engine starts, and ends where a 2.4S engine ends. I suspect that an RS 3.0 engine is even more biased toward the 'E' torque curve than an 'S' engine. So, you really aren't losing anything by using 'S' cams on a 3.0 engine, compared to your current engine!

I share your enthusiasm for the MFI engine ... only more so! But, the sound, and 'kick-in-the-pants' when an early 'S' engine hits 4500 rpm is even more compelling than the appaearance ... after all, a 230 hp RS 3.0 engine LOOKS just like a '72T engine ... not that it is a bad thing, by any means!




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Warren Hall
1973 911S Targa

Thanks Warren. I knew that it was probably just wishful thinking. I previously contacted Andial and they no longer offer the 3.0 P/Cs for the 2.4/2.7 motors. They do offer a 2.9 conversion . They said that in there opinion the magnesium case can't support a 3.0 conversion. The motor that I was going to use the MFI from has a pulled stud, not that it couldn't be useable, but I would feel safer with the aluminum case. Although the mag case and 2.7 heads would make the induction side easier.
I'll take your advice and give Pacific a call.
The news of the S cams on the larger displacement is great. My coupe has E cams and I didn't want to get into a peakier torque curve. It gets on the cam around 4500 rpm with that great deep breathing sound. I find myself wanting to keep the motor in that range. The only draw back is people driving next to me take it as a challenge. I know I don't have to explain to you and the others about that. I'm not a street racer or any other kind for that matter. I just like driving a fun agile car.
Thanks Bobby

P.S. Say hello to Mr. Bigglesworth for me.



[This message has been edited by Bobboloo (edited 04-04-2001).]