sand_man

sand_man wishes he could think about EFI at the moment! Right now the only thing on my mind is freshening up this god forsaken engine from hell!!!!

im4duke

Jeff, I feel your pain. I've only put 1k miles on my car since I bought it. Already had to replace the turbo and am now faced with the rebuild. Love the car, but certainly hoped I could have gotten more enjoyment out of it before being required to entertain a rebuild.

One of the things I am struggling with is what to do and when. That is, if I know I want to go EFI in the next year or so, what do I need to do now with my rebuild? Also, what, if anything, is it worth to do it all at the same time? I have to believe that there are savings in not having to remove the CIS later to install the the EFI hardware when I could do it during the rebuild.

Sameer, I haven't selected an ECU. There are quite a few options out there and I'm still trying to compare them. motec, autronic, AEM, PWR, haltech, megasquirt

I spoke with a few people about the protomotive engine for sale. Seems to have a questionable history. Not a risk I would take for $10k+.

David, can you describe your EFI system? Which ECU, where you sourced your hardware, etc.

PT

im4duke, I've gone through your dilemma... I rebuilt my top end 2 years ago knowing that I'll go EFI one of these days. I'm doing a full rebuild now and am going EFI.

In retrospect, I would have done a full rebuild (top & bottom end) and install the "standard" set of reliability upgrades (rod nuts/bolts, head studs, ...) as you'll definitely want them if you go EFI. I don't think there's a correlation between rebuild & EFI. Many EFI work are external to the engine; with the exception of CAM. If you are deciding between top end only or full rebuild and know you want to go EFI, then I'd suggest you consider a full rebuild now.

JMHO...

im4duke

Thanks, PT.

Can you provide more details about your rebuild and the EFI system you're going with?

sand_man

im4duke, I WAS on the fence about what to do with my broken head stud dilema...i.e. rebuild top end only and pray there are no issues with the bottom end for a while, or do the whole shootin' match! I've opted for a full rebuild. I've decided to tackle the job myself. My engine has only 42,000 on it, and I'm ALMOST positive there is nothing wrong with the parts inside, but I'm not risking it! I figure while I own this car, I get one shot to build the engine...if I have to do this job twice, my wife is shipping me and this cursed car off to Iraq! It's do or die. Plus you never know, I might sell this car. Needless to say, my troubles are now well publicised, I don't want the new owner to think I cut any corners! The used 2002 BMW M3 in Leguna Seca Blue is looking better and better to me EVERY DAY! Someone might just end up with a VERY well sorted 930! HAHAHAHA!

PT

For the bottom end, I'm doing the "standard" procedure - replacing bearings, balancing/magnaflux crank, etc. plus ARP rod bolts/nuts. I am going to inspect my rods later this week so will then decide if I keep them or replace with something stronger.

For the top end, this sooner-than-expected rebuild is caused by me bending a valve on track (car is 95% track use), so I'll likely be going with stronger valve & titanium retainer, etc. plus I'm now twin plugging the head.

For EFI, I'm an adventurer I'm going with Megasquirt - a true DIY system. I already had many of the sensors (MAP, CHT, WBO2, etc.) in the car as I have the LM-1 installed so many of those can be re-used.

im4duke

Jeff, I'm with you on the complete overhaul. If I send mine out it would be less than a month. If I DIY...well let's just say that I could be emissions exempt before I'm done.

By the way, jwl had broken headstuds too. He repainted and rebuilt his wife's 930 in about 2.5 months (judging by his postings). Lucky lady.

I had an E36 M3 years ago. Nowhere near as fun as the 930.

PT, is your twin plug mod new along with your EFI? Reason I ask, is I am under the impression that with EFI, twin-plugging is unnecessary? Am I misled or is it still a good idea to do even with EFI? Also, whre are you getting your rails and injectors, kit or fabbed?

Thanks, guys!

Another quick question: ARP or Raceware and why?

sand_man

I'm thinking that they are very close...ARP vs Raceware that is. Probably couldn't go wrong with either. I'm going with ARP because I think that's what Imagine Auto sells and I plan to buy all my parts from Stephen.

PT

To me twin plug & EFI are 2 different issues - twin plug helps prevent detonation. Even with EFI, ignition can still be a problem. In my case, the car is on track most of the time; running in high RPM and full boost often, so I want to make 200% sure that I can do everything I can to minimize chances of detonation.

ARP/Raceware - Dilavar has been confirmed by most to be a time bomb. Some suggests using 993 SS studs but so far it seems that nobody had problems with ARP/Raceware hence my choice. For fuel rails/intake, I'm going to use a 3.2 intake.

DonE

Twin plug allows a little more timing, but if the ECU is crap, nothing will protect against detonation. My engine burnt about 3 months ago because the TEC3 firmware caused my enrichment values to shift (lean). It took only 4 - 5 seconds to crack 3 cylinders and burn a hole in one because of improper fuel delivery.

In any event, twin plug makes a big difference on pistons with high domes or large volume cylinders where flame front travel is affected by volume or distance traveled. For our turbos, twin plug is very good at high rpm where we do not want a lot of advance under boost, but we want the ignition to be as efficient as possible in the combustion chamber. This timing issue is why a crank fire system is superior to a distributor - 12 degrees at idle, 30 degrees at 3000 rpm, dropping to 22 degrees at WOT (not to mention cold weather advance at idle, retard at high inlet temps, etc).

One other point, a twin plug cylinder will run slightly cooler at a given timing point than a single at the same timing point.

If you want proof not to use 993 studs on a high performance 930, look at my rebuild web page where the studs stretched and let the heads lift a bit.

For a bit of humor, I originally budgeted $9000 for the rebuild and conversion to EFI. It doubled fast.

PorschePhD

A MEN!! Someone finally believes me!

im4duke

There appears to be a fair deal on ARP head studs on ebay right now. $422 delivered.

http://cgi.ebay.com/ebaymotors/ARP-H...QQcmdZViewItem

sand_man

I'm not taking any chances! I almost bought an Innovate LM-1 from that seller. It took almost three weeks for him to respond to my question. In the mean time, I started reading some of his Ebay feeback....it wasn't all that great! Even if it costs slightly more, I'm buying from Stephen!

DonE

This is where I bought mine - rod bolts and head studs. Delivered in a couple of days and even followed up with me when they drop shipped the rod bolts from ARP. Even though it was one transaction, I recommend them.

125shifter

I'm trying to find humor in it, but it's difficult.

All my non-Porsche car buddies keep reminding me that I could have a couple year old 996 for what I have in the 930. To which I respond that a 996 doesn't have 500+ rwhp and weight 2750lbs.