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DRV2FST 02-26-2007 07:25 AM

Engine Rebuild EFI results

It is still a 3.3 but with JE Pistons. Tec3r EFI with sequential injection running 72 lb injectors. It has a Garrett Turbo Charger and a Borla Muffler. All work done by Pat Williams Racing. I had some work done by other shops before but none of that work held up. Pat redid everything.

Questions, Comments?

hobieboy 02-26-2007 07:31 AM

Any idea why there is a (relatively) huge dip in AFR at ~5600 rpm?

Are you using 3.2 intake? And I'm curious about your injector duty cycle (I'm using 52lb ones and am running out).


DRV2FST 02-26-2007 07:33 AM

I don't have the EFI MAP in my possesion just yet, so I don't know why the AFR behaves that way. I am using the 3.2 intake. I'll run a datalog later today and gather some information about injector duty cycle.

oms930 02-26-2007 08:08 AM

The numbers look really good especially at 0.85 bar!

Would be interested in any other details as well, for example: which Garrett do you have? A/R and Trim? How about the cams?


David 02-26-2007 08:35 AM

Those numbers are huge for 0.85 bar and the curve looks really smooth for a monster turbo. What are the full specs?

RarlyL8 02-26-2007 08:52 AM

Wow, nice job. Get that A/F curve straightened out and there is even more free power.

Jim2 02-26-2007 09:40 AM


Questions, Comments?
A little over 500 at the wheels at .85 Bar. So this would only be mid 500 at the FW.

Rather measly results.

Joking aside, do you have an explanation for the rapid drop in torque above 6000. Stock cams?

So what would 1.0 bar do? or are we not going there.

Sounds like similar performance to Mikes turbo.

David (125 shifter), was your torque curve still flat above 6000?


DRV2FST 02-26-2007 10:55 AM

More Specs to answer some questions:

Euro SC Twin Plug Heads
Large Intake valves
Webb cams 964S (05-302)

I have a 1.0 bar spring in the WG but measured at the manifold it is only getting to .85. Measured at the brake booster it reads higher for some reason.

I certainly could use some more tuning on the A/F curve. I got tired of waiting on the car and took it before they got it fine tuned. I'll drop it back off to Pat in a month or so when I go on vacation.

David 02-26-2007 12:40 PM

Where is the MAP sensor connected? I wonder if it's not getting a true signal?

Either way, that's great output for your setup.

My curves look very similar to those just lower :(. At 0.7 bar, my peak hp is 390 and peak torque is 340. We ran it up to 7000 rpm, but I think peak hp was about 6000 just like DRV2FST's curve.

DRV2FST 02-26-2007 02:32 PM

Map Sensor
Here are some photos of the engine bay from slightly different angles.

I guess this is the MAP sensor. Am I correct?

WydRyd 02-26-2007 03:19 PM

Very nice indeed! Congrats and enjoy! :cool:

hobieboy 02-26-2007 04:05 PM

Yes, the one in the bottom picture is the MAP sensor. Where does the hose connect to?

DRV2FST 02-26-2007 04:09 PM

Which hose?

hobieboy 02-26-2007 04:17 PM


Originally posted by DRV2FST
Which hose?
The hose from the MAP sensor :)

DRV2FST 02-26-2007 04:32 PM

To the bottom of the throttle body. It is the middle one in this photo.

DRV2FST 02-26-2007 04:34 PM

By the way, it just passed emissions without a CAT. I'll post the story in the general 911 technical forum.

DDDD 02-26-2007 04:55 PM

Hey, DRV2FST, I like your project and I sent you a private message about it.

DRV2FST 02-26-2007 05:12 PM

thanks, PM replied

beepbeep 02-27-2007 12:39 AM

Great results! You/your builder did everything "right".

- Garrett turbo (you never mentioned which one? I presume GT35R or GT40R) and no KKK stuff
- EFI and no CIS
- Carrera intake and not sub-optimal CIS intake
- Bigger IC
- Twin plugs
- JE pistons.
- Correctly sized injectors from scratch

Also, depending on where you take your boost reading from, you might get higher results before intercooler compared to plenum. Your intercooler might be a bit too small. I guess that your internal boost gauge is fed off the brake-booster line and that dyno papers used MAP-sensor, right?

AFR curve is conservative, with rich readings where V/E is supposed to be high. It would be informative to see VE table from your EFI. I believe you could pick some extra torque in the area where AFR's are low by leaning them a tad but it all depends on VE at that revs. If car is breathing "well" where AFR's are in 10's then Pat Williams probably kept it rich to keep it safe which is a sign of a pro. It's better to have a bullet-proof engine with slightly less torque at lower revs than one with hole in a piston ;)

David 02-27-2007 04:58 AM

Since there's air flow through the throttle body where the MAP sensor is reading, it will read a lower pressure than in the manifold. I'd trust the boost gauge since it's getting pressure from the side of the manifold where there's less flow.

Even at 1.0 bar, it's really excellent results.

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