CIS to EFI kit

[djb_rh]

Anyone got a clue why my car has started idling at random places between 1600 and 3000 RPMs? It seems to "stick" at a given idle for a while (as in each time I return to idle), but doesn't necessarily stay through the next on/off cycle. It can change without a key off event. It locks in on whatever it feels like being at pretty well, but obviously idling at 3k is quite annoying. Or anything over 1600 or so, really.

What's perplexing is that it isn't the same wrong. Thoughts?

Edited to add: Throttle linkage and return spring *appears* to be fine. Blipping the throttle doesn't do anything to help. It'll just return to whatever wrong idle it's currently stuck at.


--Donnie

[antares]

So Nux ... I take it you have a 3.0 ? ... with your pictured setup what was the neighborhood cost of going with this throttle body setup route with all hardware/software as pictured ... and what are your new hotter cams spec'a ? - Thanks dave

[Nux]

Originally Posted by antares

So Nux ... I take it you have a 3.0 ? ... with your pictured setup what was the neighborhood cost of going with this throttle body setup route with all hardware/software as pictured ... and what are your new hotter cams spec'a ? - Thanks dave

Dave,

The ITB's came from Clay (Closed Course Motorsport). I believe he still sell this set for 1800$. I had the Bitz kit installed and uses that as a base. You can go that way or source the parts individually. You'll need an ECU, wiring harness, injectors and a few sensors. Prices are1000-2500$, depending on what system you prefer.

If you do it you self, its at minimum 3000$ all in. You could also ask someone like Al Kosmal to make a cool kit and save you the headache.

I have a 3.2ss Max Moritz conversion with a DC20 cam which is essentially a 964+ cam. Falls between 993ss and 964.

[mikedsilva]

I think Al Kosmal will soon be providing itbs, designed by Rama from Racehead Engineering in Australia.
RHD Engineering | Porsche Bolt on ITB Kit

I have a set of his ITBs on my 3.0. He provides fuel rails, linkages, varying trumpets etc.. Here is a short video I took of his system yesterday. (forgive the sloppy gear change)
https://www.youtube.com/watch?v=LjTOLkeYe1Y

[Nux]

Wow that is cheap!!!!! And looks good too!!!

[antares]

Thanks for this much needed info ... so what a 964+ cam somewhat like a 964 cam, offers an extended torque band encompassing both bottom end grunt and upper end increase rpm torque from stock or just repositions the torque band higher up the rpm scale range but leaving the bottom end grunt with something to be desired ? - dave

Edit: It has also occurred to me that for this EFI cost of $ 3,200 bucks or so I could just as well save that and just sell my good 3.0 and put another 4 grand or so on top of that and go buy a good used 964 motor w/native EDIS spark/advance controls builtin and be ditching the CIS scenario at the same time without all the toe touching aerobics of installing a megasquirt or Tbits setup ...just saying or am I missing something with that ? -dave

[Nux]

The EFI kit provides significant improvements in torque and will allow the use of hotter cams without compromising low end too much. I've have no issues with mine and it pulls very strong to 7000rpm, weras the SC cam is done way before that.

Also, because of the better atomisation of fuel and the ability to fine tune the fuel delivery, it's possible to run higher compression than the usually recommended. I know this is highly controversial here, but I know several builds with EFI running 10+ CR with single plug and has done so safely for years.

Oh and about that 3.6: I haven't seen one for 7k for a while, it's more like 12-14. And then you'll need a flywheel conversion for your 915 tranny (1200$), a new exhaust system (used 993 heat exchanges being cheapest) say 500$, new muffler 500$, and a chip 500$, adaptor for engine mounts, front oil cooler and hoses etc etc. It's an easy 15 at least IMO anyway.

Go with the EFI. Your car will be transformed!

[clutch-monkey]

Originally Posted by mikedsilva

I think Al Kosmal will soon be providing itbs, designed by Rama from Racehead Engineering in Australia.
RHD Engineering | Porsche Bolt on ITB Kit

I have a set of his ITBs on my 3.0. He provides fuel rails, linkages, varying trumpets etc.. Here is a short video I took of his system yesterday. (forgive the sloppy gear change)
https://www.youtube.com/watch?v=LjTOLkeYe1Y

i like bill's stuff, seen it on a fair few bmw's. nice to see he is expanding to 911's!

[safe]

Originally Posted by Nux

Oh and about that 3.6: I haven't seen one for 7k for a while, it's more like 12-14. And then you'll need a flywheel conversion for your 915 tranny (1200$), a new exhaust system (used 993 heat exchanges being cheapest) say 500$, new muffler 500$, and a chip 500$, adaptor for engine mounts, front oil cooler and hoses etc etc. It's an easy 15 at least IMO anyway.

My 7k 3.6 (a few year ago) ended up at twice that after a needed rebuild and a few small upgrades, nothing exotic.... cams, aftermarket EFI, tuning, headers.
Oh, and the g50 conversion I decided I needed ended up with another 4k and recently 3k on top of that with a rebuild, cause it wasn't in the greatest condition....

[antares]

... all good to know but already have the conversion kit and a muffler ... sell mine for say 8k put 3k into the purchase of a 3.6 , add another 1,500 misc and pretty much plug and play time ... personally don't need to G50 it or tweek it out ... just so it starts and runs reliably ... It will have all the punch needed.... not a bad idea if I can make it work ... I would have at minimum around 2,400 all new going the Tbit or Squirt route and still not have EDIS ... so let's say upwards to around 4k and still have CIS stock cams in the motor .... so buying a good used 3.6 and adding another 1,500 out of pocket I should have a good rocket ship for about 4 grand more than just going EFI...

I do admit that I should of done this around 2006 or so when I was thinking of doing it, the cost of the motors were much less and less beat to death than what is no doubt out there now .... Just saying - dave

[l_turn9]

I have had an intermittent problem where the 3A fuse protecting the ECU was fine with no issues since 2009 when I installed this excellent system. A couple of months ago, while the car idled and warmed up in my driveway. it died. I eventually found & replaced the blown fuse, turned the key on and the fuse blew again. I disconnected the ECU, and turned the key on, and the fuse did not blow! To me that says there's a problem between the 3A fuse and the ECU. There is nothing but wiring between the ECU and the 3A Fuse. Tony rec'd the ECU and found zero problems. He then installed my ECU into his personal 911 and it started right up without any issues. I get the ECU in return mail and reinstall it. This time, I find I am not having blown fuses anymore and Tony says he did nothing to the ECU. It's really baffling! But I must compliment Tony Bitz who has stayed right with me. He even writes and offers possible solutions that I should look into! The 3A fuse blew once more last week,
I replaced it with a new fuse and all is well. So far, so good after a week of repeated starts during the last week. Tony is still writing and offering suggestions for me to check out. I cannot give Tony enough credit for staying on top of my trouble and continuing to offer support and suggestions.
If you're reading this Tony, THANKS! I am confident I will solve this problem with your help!
BTW, Anyone have any ideas about what might cause the fuse to blow that has been so bullet-proof for 10 years? TIA,
LarryT
74 911 W/Bitz Single TB EFI.

[wreckah]

Hey Larry, a wire that has rubbed through somewhere?

[70SWT]

Originally Posted by wreckah

Hey Larry, a wire that has rubbed through somewhere?

This was my thought - with usage since 2009, that's enough time for a short to develop somewhere. Moving things around to pull the ECU and reinstall may have just temporarily relieved the short. It may return. I'd go through the relevant parts of the loom and look for it just in case.

[l_turn9]

Yep, you 2 may be right, but the loom is extremely sturdy. It's a heavy gray material that completely covers the harness. I'll ask T Bitz what the material is. Also, I must explain that while I have had the Bitz system since 2009, my health has steadily gotten worse so I have been able to use the 911 less and less. I don't think I've done more than drive a 3 mi loop around my neighborhood since my 4th Knee replacement on left leg 3 years ago made that leg 4" shorter than the other. It's hard to drive safely when the seat is adjusted so my L leg can operate the clutch pedal, because then I am too close for my R leg to operate the accelerator and brake safely. I probably have driven it no more than 30K mi., maybe less. I'll check my logs and try to get a better understanding of the actual miles I have driven. In any case, there would have been zero aggressive driving or DE's during the time.
Thanks for your comments and suggestions, they are appreciated!
Sincerely,
Larry

[tbitz]

Below are the specs on the main wire harness from the ECU. It's top of the line automotive grade. On top of that is a expandable sleeve which keeps the wire bundle tightly together as it is routed into the engine bay. Grommets are supplied to provide a smooth entry into sheet metal tunnel.

[l_turn9]

Thanks for those Specs Tony. Very helpful, and yes I remember the grommets provided. I used them whenever I entered metal. Wasn't able to get the car up on jack stands today like i wanted, but maybe tomorrow.
Thanks again for the help...
Larry
74 911 w/Bitz EFI

[coomo]

Originally Posted by mikedsilva

I think Al Kosmal will soon be providing itbs, designed by Rama from Racehead Engineering in Australia.
RHD Engineering | Porsche Bolt on ITB Kit

I have a set of his ITBs on my 3.0. He provides fuel rails, linkages, varying trumpets etc.. Here is a short video I took of his system yesterday. (forgive the sloppy gear change)
https://www.youtube.com/watch?v=LjTOLkeYe1Y

Just got me interested, then it all vanishes...........

[mikedsilva]

Originally Posted by coomo

Just got me interested, then it all vanishes...........

Here is the new link...

[ThatTougeGuy]

So with the yahoo group dead, does anyone happen to know how to get the the correct updated MS1 Extra firmware? Was wanting to update, but none of the ones on tunerstudio will work.

[tbitz]

Shoot me an email through the www.bitzracing.com website and I can provide that.