Chet 930

I promised I would share some of my thoughts about the EFI conversion I had done recently. It took a little longer than I had planned to get a scope of everything, but being a single Dad with two young boys and the work I do make for little time to spend with the 930.

First off, Stephen did a sweet job overall. We had a couple of small issues to sort out which he worked diligently with me on. Since the dyno tune was done back in December when it was very cold in Kansas, there was some need for adjustment once the car arrived here in California with the warmer temps. There was also an ignition coil wire connection that somehow worked its way loose and caused some havoc with AFR's. Once Stephen and I corrected those small items, I made a few other adjustments for my own liking. I have to say, its never been so easy to make adjustments to the motor before. Sitting in the car making instant changes on the laptop and not smelling like exhaust fumes when I'm done!

Anyhow, what can I say......the drivability is great. Most 930 owners would think theres a bigger motor pushing the car around instead of the 3.0. The low end torque is nice even all the way down to 1000 rpms in gear. Cruising around smoothly,easy and steady gets me 14:7 AFR with full enrichment into as much as the 11:7 area.

Acceleration is probably close to the same as before the conversion, but the motors longevity isnt quite an issue anymore. I had the motor wound pretty tight before at 430rwhp on CIS and it came off the dyno with EFI after tuning it with the same power output although the torque band was a little wider and the boost level was lowered.

But with the additional fuel and management abilities, I can definetly make some adjustments along with some larger cams, headers or even a carrera manifold and easily crank out some more ponies and torque if need be. After driving it, Stephen strongly feels it will run down some 3.3 and 3.4 motored 930's as it is. I'll only say that it WILL cover a lot of ground pretty quick.

80 percent of my original reason for the conversion was to have the ability to manage the motor and pass California smog tests. The other 20 percent was for the additional performance platform. As far as I can see, my goal has been reached. It was well worth the conversion at this point.

911addict

Chet, sounds like you're enjoying yourself after the long wait ;-)

Do I understand correctly? 430 REAR WHEEL HP? ... that's around 490 FLYWHEEL BHP on CIS!
What mods did you have? I'm not surprised it was a bit stretched, I guess you had all sorts of reliability issues, did you?

Chet 930

You know......I really didnt. I didnt have one single problem other than passing California smog tests. The Dyno pulls were done by Stephen before and after. Mods are 37mm intakes, SC cams, K27 (standard one at that) and full bay intercooler. The heat exchangers are the factory units from my 89 930 and the exhaust muffler was a free flowing unit. Thats it. Nothing special.

DDD

I was under the impression that EFI would yield more power, but from what you say it is more of a driveability improvement (and safety)?

All the fine tuning didn't add up to much more power. Does the car feel quicker?

Chet 930

It made the same power with less boost and a little broader torque curve. One thing I omitted was that I can crank the boost back up and add more fuel. I'll make more power doing so but the longevity of the motor is more important to me at this point. I have no problem building the motor again if I need to but the time to do it is what has changed for me. Not to mention that this car has hardly seen the road in the last couple few years.

jimculp

Nice writeup. When you make changes are you changing the timing, fuel, or both? I assume you installed Autronic ECU? What setup did you use for spark?

Daley88930

The best part is the viability of a 930 with CA standards. Chuck, what was your boost previously? and what is normal now? Thanks

Olli

Thanks for the write-up Chet and happy to hear your objectives were met. Sounds like a good job.

Sounds to me the best part will be (along with passing CA smog inspections) the ability to do all your adjustments using the software to do it. Getting into the engine and doing things yourself is a lot of fun but sometimes one finds that there are limitations to the fun one can have, like arthritis in the fingers and joints that will dampen some of the excitement in it. But understanding what goes on and doing it comfortably with a laptop is positively a nice solution to bypass some of those pains. I don't know if you have any or not, but that is a problem I have.

nathanUK '81 930 G50

Same max power at less boost !

RarlyL8

Ah, but the possibly the most important question has not been asked.
At what cost?
I'm guessing you gatta want your high power 930 to pass smog pretty badly to pony up the bux on that one. Glad it worked out for you. High powered legal 930s may be a rare breed in CA.

PorschePhD

The cost....less than he was going to spend stretching a motor on CIS like that. Lets see cost of an engine rebuild with a hole in a piston OR an EFI kit. Far cheaper than the rebuild.

JBL930

Chet, to get near 500bhp at the crank out of a 3.0ltr with a standard K27 you must have been at something like 1.5bar, what were you doing for the extra fuel? And which nutter set the car up like that?

NineMeister

It's the work of a madman for sure, making a 930 that powerful. Should lock them up and throw away the key

Stevie 77 930

Chet,

How is it that you are able to pass smog ? What about visual test....air pump, exhaust, egr, etc... Are you still running the factory late(er) model exhaust system? The smog is the only thing holding me back... I can only assume you are running very clean on the smog dyno.

chet 77 930

I decided to hit the log off button yesterday for some reason (I usually dont). Doing so cleared the cookies in my laptop and I couldnt remember my password to get back on. Had to re-register.

JBL930....the nutter who set the motor up that way was me. I built the motor also. And no, I didnt have to run 1.5 bar. The secret to the power is in the cylinder head porting as is with many naturally aspirated motors. Many people I've talked to who wrench on 930 motors kinda all say the same thing....."its forced induction, theres no need for porting". I think I've proved that wrong. Volumetric efficiency is what it boils down to.
I took the limited skills I aquired from building small and big block Chevrolet motors and applied what I knew. I seen a few motors that pounded out some big ponies from things like angle milling that was done in such a way that not only did it raise compression ratios but improved airflow as well. Those kinds of things are what I learned some years back.
Contrary to what turbo minds think, port velocites are just as important in a low compression turbo motor as is a naturally aspirated one for drivability purposes. I didnt even share what I did with Stephen, I dont know if he saw it when the intake manifold was off either.
An EFI conversion alone isnt going to make that kind of power. In my case it only gave the fuel/management necessary to maintain some longevity and a platform for more future ponies if I really put my mind to it. My motor had good low rpm drivability even before it was converted, BUT it did so at the trade off of running extremely rich CO's too. I was constantly wiping the black soot off my rear bumper every other day. I also couldnt walk by the tail pipe in the morning with dress clothes on without absorbing some unwanted exhaust smell.
In conjuction to the CIS system I had an Andial FE system as well as a euro fuel head and fuel lines which 77's already come with.

Stevie...I havent had it smogged yet with the EFI, but from the AFR guage I installed recently, I'm starting to feel confident that it'll pass the dyno and sniffer without even having to make any adjustments. It runs real clean. Prior to this, I had everything in place for the visual, but I had a bear of a time getting the car to run at specs and pass. The main issue was the dizzy not wanting to co-operate with the SC cams. I couldnt get the motor at 5 degrees (btdc or atdc I dont remember which now) at idle and the CO at spec without it running like an absolute slug! It would barely even complete the dyno test.
My car has a "non catalyst" sticker on it. I dont have the original exhaust system anymore but instead installed the stock OEM exhaust form my 89 930. I ran the cat as well for the smog test. The tech was cool about that and was satisfied that it could be a replacement for the thermal reactors. It would pass but just barely. I think if I would have sneezed anywhere near the car the last time it was on the dyno it would have been enough to fail it!

Daley...I dont have the exact boost numbers. Stephen had them when he dynoed the car before and after. I need to get a true boost gauge. My experience with the tach boost gauge and the aftermarket ones indicated that there was less boost in the motor than what the tach guage showed. Prior to the conversion my tach showed 1 bar and sometimes a little over. The ECU is measuring it in KPA's (and I've seen it on the laptop) but that unit of measurment is so foreign to me that it doesnt even register in my mind right off the bat.

Jim....the changes are some of the fuel cells, timing (below the 100% load threshold) and small things like max rpm (brought it down to redline), overboost margin to get rid of a spike that was shutting the motor down in one spot etc etc. Yes, the ECU is an Autronic SM4. Spark is a M&W Pro10.