Mfi or itb with twin turbos

1WIDE911 · 02-24-2009, 01:37 PM

Hi guys,

Kinda of new to the 911 world but I am fast learning the ends and outs. I had quick question though, I was wondering if anyone on here was running mechanical fuel injection or idependent throttle bodies or even carbs with a twin turbo set up. And if there are what kind of fuel injection system and twin turbo set up were they using and whatkind of aftermarket systems were out there for MFI and twin turbos. Any help would be great.

thanks a bunch

JMA-RUF · 02-24-2009, 01:57 PM

Never seen a twin turbo conversion on a MFI/CIS car, sorry. All have been EFI'd.

tarheelturbo · 02-24-2009, 02:31 PM

i've wondered the same thing myself.. but from what i've gathered...
tuning high horsepower MFI engines is a lost art or atleast something that no one wants to mess with considering what can be done with EFI, and i think that you would run into enough expense trying to convert one over that in the end it would just make alot more sense to go the EFI route..
please chime in if i'm wrong... but thats where all the information has lead me..
based on the cost of building a high hp twin turbo motor is in this world.. i can't imagine wanting to spend the money to create a individual throttle body setup for it.. but i would love to see it if someone has!!

JBL930 · 02-24-2009, 02:47 PM

ITB's with EFI would be great, plenty of pics when the time comes please

RarlyL8 · RarlyL8's Garage

There are a few ITB EFI Twin Turbo 930's on this board. VoitureLtd has one that AMAC had built a few years back. MFI Twin Turbos are old school and mostly seen in pictures nowdays.
I threw together a CIS based Twin Turbo but had to stop the project when time became an issue. You can see it in my thread listed below. EFI is definitely the most elegant way to do twins. ITB's seem to be more for looks than function in that application.

TimT · 02-24-2009, 04:19 PM

A bit of a topic bend...

We took a perfectly good cupcar

And made it into a twin turbo, using factory parts

And built a twin turbo engine for it... doesnt have ITBs but makes what we call 7&7 700 hp and almost 700 lb/ft of torque..

cant access my website now and cant link any pics of the finished car...

TimT · 02-24-2009, 04:20 PM

oops missed a pic.... factory turbo quarter fitted

purplehaze · 02-24-2009, 04:53 PM

1WIDE911 -

What do you have now, and what are you wanting to do?

Those crazy Rudtner guys in Long Island have done turbo'd ITB's I believe, but I think it was also an EFI controlled puppy (likely Haltech).

I've got a twin turbo set up I need to sell as well......

Tell us more about your goals, your dreams,......forget that, just stick with your goals.

TimT · 02-24-2009, 05:33 PM

Yes we do Haltech

There is a really good guy here on LI that can rebuild MFI pumps....he keeps threatening to retire though... Has all the tools to rebuild the pumps..but even better has his 50 years of experience..

And we have turbo ITBs no twin turbo ITBs though..yet

voitureltd · 03:53 PM

Quote:

Originally Posted by tarheelturbo

i've wondered the same thing myself.. but from what i've gathered...
tuning high horsepower MFI engines is a lost art or atleast something that no one wants to mess with considering what can be done with EFI, and i think that you would run into enough expense trying to convert one over that in the end it would just make alot more sense to go the EFI route..
please chime in if i'm wrong... but thats where all the information has lead me..
based on the cost of building a high hp twin turbo motor is in this world.. i can't imagine wanting to spend the money to create a individual throttle body setup for it.. but i would love to see it if someone has!!

Here are a few photos of the AMAK's 3.5 liter, ITB, twin turbo, MFI, Norwood built car that RARLYL8 mentioned. I keep it at around 525 RWHP but has pulled well over 700 at higher boost and race gas. I need to add more safety equipment and suspension upgrades to be comfortable running with the maximum HP.

1WIDE911 · 02-25-2009, 03:01 AM

Thanks for all the info so far guys, I haven't bought anything yet, been quietly looking for a early 911 roller, but trying to gather some information together. Motor wise I had thought about the using the a 930 or 993 block, with a stroker kit and heads from CMW, WEB racing cams and possibly a crank trigger ignition. I like the thought of the ITB or the MFI. I have seen pictures of the 935 engine and that got my thoughts stirring on the MFI/twin turbo route. Body wise I was planning on the 74 RSR 15" fenders in the rear but the earlier 73 RSR 9" flairs in the front. Not sure yet but wanted alot of muscle to back up all that meat in the backend. I know its kind of hard to say at this point what all my options are since I haven't bought anything yet, but I like to have a game plan, so I can hit the ground running

equality72521 · 02-25-2009, 03:21 AM

Quote:

Originally Posted by TimT

Yes we do Haltech

Which model?

JBL930 · 02-25-2009, 03:34 AM

Fantastic

TimT · 02-25-2009, 08:44 AM

Quote:

Which model?

We can do any haltech, or any other brand of EFI. We have been installing EFI systems for about 15 years

VZ935 · VZ935's Garage

We just put a new motor in my 935 .. MFI of course because that's how Porsche rolled back in the 70-80's

Then I have Motec on this one but with a single throttle body works great . Cheaper, less moving parts than individual throttle bodies but of course leaves some power on the table. Motor did a dependable 600+ at 1.1 and never broke and looked like new inside after 60 hours of run time

Then on my buddy Bob's car we did Jenvees with Motec on an air motor but with water intercoolers

purplehaze · 02-26-2009, 05:41 AM

Quote:

Originally Posted by voitureltd

Here are a few photos of the AMAK's 3.5 liter, .......

Tony -

Do you have any photos of the spoiler outlets - where they connect to the turbo intakes? That looks like a really clever design.

Thanks -

purplehaze · 02-26-2009, 05:44 AM

Quote:

Originally Posted by VZ935

....

Holy Cr@p! Beautiful VZ!

I love the symmetry and simplicity of the dual turbos in the rear. You've got a great collection!

JBL930 · 02-26-2009, 06:54 AM

Those flat fans are amazing, do you have a shroud from the underside of the intercooler to the fan so it draws every bit of air through it?

VZ935 · VZ935's Garage

Quote:

Originally Posted by JBL930

Those flat fans are amazing, do you have a shroud from the underside of the intercooler to the fan so it draws every bit of air through it?

There is actually an aluminum piece that fits on top of the IC and mates up the the upening that looks like a huge NACA duct in the roof overlay/rear window... then vents out the bottom of the rear deck. The air basically gets pulled right though .

voitureltd · 02-26-2009, 08:42 AM

Quote:

Originally Posted by purplehaze

Tony -

Do you have any photos of the spoiler outlets - where they connect to the turbo intakes? That looks like a really clever design.

Thanks -

Seems to work well. I just have to remember to cover the turbo intakes when the tail is up so something doesn't get dropped in there.