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Bitz Kit Install in Stock '77 911S

I've decided to give up on trying to get my CIS working perfectly and have placed the order for a Bitz kit and gathering the rest of the parts as well.

Last spring, I removed the entire CIS and replaced all the gaskets, hoses, seals and air box along with testing as many components as I could find instructions for. I set AFR to spec and still the car didn't have much acceleration from idle to 2500rpm and it had a slight bucking at steady speed- drove great under acceleration. I started a thread to try and sort it out: Drivability Issues '77 CIS

I know that CIS will work very good and maybe if I would have put more money and time in to it, it might have worked- how much money, how much time, who knows? I think most would agree that with all the advances in fuel management that no engineer would put CIS in a new engine design- even if there were no emission or fuel economy standards. It was a good system in its day.

So, I decided to throw in the towel and go EFI. After a little searching here and word of mouth, I decided on the Bitz as it was significantly less expense that the other choices and it appeared that it works well with minimal fussing.
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Rutager West

1977 911S Targa Chocolate Brown

Last edited by rwest; 08-20-2017 at 06:38 AM.. Reason: And, doesn't have an "m" in it
Old 08-20-2017, 06:19 AM
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Always exciting to be able to attach the service cover to the rear end- makes me feel like a serious mechanic.

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1977 911S Targa Chocolate Brown
Old 08-20-2017, 06:21 AM
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The original fuel regulator that is spec'd is NLA, so in another thread, an Aeroquip unit was recommended, I also upgraded to a wide band O2 sensor so the system could get AFRs not just rich or lean.

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Old 08-20-2017, 06:24 AM
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There are some choices that need to be made and the big one is whether or not you want to strip all the CIS off for what they refer to as the "clean" look, or leave the air box and filter in place.

My first though was go with the clean look as it makes for easy accessibility in the engine compartment, of course once you get rid of all the extra CIS sensors and cold start valve from behind the air box, there isn't anything you need to access! The clean look requires several other parts to be purchased and to me, almost looks too bare.

Now, nothing looks quite as nice as ITB's but I don't use the car enough to drop that kind of money and besides it seems like once you start getting too complicated, the tuning can be a real headache- if I wanted to tinker endlessly, I would have left the CIS. No offense to those that have jumped in with both feet, the ITB's are awesome and I'm sure they get the last bit of power out of the engine.

My decision to keep the engine looking somewhat stock was based on being able to still use the standard air filter and having places to still connect the evaporative emissions stuff and the oil breather without having to re- engineer it all.

The Bitz is supposed to arrive Tuesday and I'm welcome to suggestions and advice and hope to also share my experience and any snags or tips I find. I'm not going to write a DIY type article as the Bitz has a 99 page manual already.

Rutager
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Old 08-20-2017, 06:36 AM
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Old 08-20-2017, 06:37 AM
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rwest,

Good luck with the EFI project! I, also have a 77 911S and am having a very frustrating time with the CIS right now.. Again, good luck!!
Old 08-20-2017, 06:42 AM
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Just about every post I read about the Bitz kit was positive, in fact I think the only one that didn't have good luck had tried it on a highly modified engine and if I remember right, that caused a less than ideal vacuum.

I'm in a smidge over $2,000 right now and that should be close to the final amount.

I really wonder if at a certain point all of the 7 or 8 (or more) different sensors and components of CIS will test in spec, but are each off enough that the accumulated errors will cause an issue that can't be solved short of guessing and replacing?
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1977 911S Targa Chocolate Brown
Old 08-20-2017, 07:01 AM
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Rutager, I'm lucky in that my 82 SC, bought in 2014 with the motor out and apart, had a CIS system that had been expensievly maintained and has worked nicely since I rebuilt and first started the motor. The receipts show three WUR replacements, injectors and other components stuff in the original owner's tenure, from 1982-2013. My SC also has genuinely functional A/C (again, an expensive achievement of the OO, with Griffiths components including a Sanden compressor). I would never sacrifice this element because it adds so much utility in making the car a viable driver in warm/humid conditions.

That said, I have read the Bitz manual in full and spent time on Tony's website, and if I were to install the system, I too would be considering which "look" to adopt, because I feel the cut-down airbox look with an aftermarket air filter on the end of a polished cold air intake tube looks awful, and to me, looks under the hood matter. Not that the CIS system is by any means handsome, but it is what we're accustomed to.

There are references to and some photos of a neatly fabricated aluminum intake system that once existed, but the fellow who made them isn't doing so anymore...I asked.

None of this should be implied as any criticism of the Bitz system. If I get to the point where I need to go that route, I imagine myself scouring junk yards for pieces (from other cars) where i could start with the cut down CIS airbox, but build up an intake system that looked non-CIS, but somehow "factory", even if only in my mind. No Pep Boys cold air kit!

Based on what I've read, you will be very happy with your Bitz upgrade. Please do show us the finished results. John in CT.
Old 08-20-2017, 07:17 AM
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Am interested in your results. Are you planning on any additional upgrades to the ignition, or keeping the distributor and your MSD setup?

My CIS still seems to function well, but the car won't run right unless I'm filling with non-ethanol fuel and at some point that will become impossible to get...
Old 08-20-2017, 07:21 AM
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At the price Tony has priced his kit, I'd ditch CIS in a heartbeat.

Well thought out kit.
Old 08-20-2017, 07:55 AM
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Quote:
Originally Posted by fanaudical View Post
Am interested in your results. Are you planning on any additional upgrades to the ignition, or keeping the distributor and your MSD setup?

My CIS still seems to function well, but the car won't run right unless I'm filling with non-ethanol fuel and at some point that will become impossible to get...
I just had the distributor rebuild and everything else in the ignition is new or just a year old, so at this point I'm leaving the ignition as is. I've gathered that electronic ignition isn't as big of a deal as the EFI as far as bang for buck.
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Old 08-20-2017, 08:27 AM
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Quote:
Originally Posted by Tippy View Post
At the price Tony has priced his kit, I'd ditch CIS in a heartbeat.

Well thought out kit.
I agree, you do still have to add another few hundred in parts though- injectors, fuel pressure regulator and then there are a few optional items you can add such as a better O2 sensor.
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Old 08-20-2017, 08:29 AM
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Quote:
Originally Posted by jjeffries View Post
Rutager, I'm lucky in that my 82 SC, bought in 2014 with the motor out and apart, had a CIS system that had been expensievly maintained and has worked nicely since I rebuilt and first started the motor. The receipts show three WUR replacements, injectors and other components stuff in the original owner's tenure, from 1982-2013. My SC also has genuinely functional A/C (again, an expensive achievement of the OO, with Griffiths components including a Sanden compressor). I would never sacrifice this element because it adds so much utility in making the car a viable driver in warm/humid conditions.

That said, I have read the Bitz manual in full and spent time on Tony's website, and if I were to install the system, I too would be considering which "look" to adopt, because I feel the cut-down airbox look with an aftermarket air filter on the end of a polished cold air intake tube looks awful, and to me, looks under the hood matter. Not that the CIS system is by any means handsome, but it is what we're accustomed to.

There are references to and some photos of a neatly fabricated aluminum intake system that once existed, but the fellow who made them isn't doing so anymore...I asked.

None of this should be implied as any criticism of the Bitz system. If I get to the point where I need to go that route, I imagine myself scouring junk yards for pieces (from other cars) where i could start with the cut down CIS airbox, but build up an intake system that looked non-CIS, but somehow "factory", even if only in my mind. No Pep Boys cold air kit!

Based on what I've read, you will be very happy with your Bitz upgrade. Please do show us the finished results. John in CT.
Yes, I wasn't thrilled with the clean look, I'm guessing that the market is too small for someone to sell a replacement manifold that would look nice. I was milling around in my head of having something machined and then moving the throttle bodies to the center to even out distance to each cylinder and then putting the air filter on top, but then my mind pictured a round air filter housing on the intakes and all of a sudden I got a vision of the single carb setup on an old dodge or something!

ITBs are really the way to go to make the engine look cool, but price and tuning hassle will keep them out of my hands, at least for now.
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Old 08-20-2017, 08:35 AM
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ITBs are really the way to go to make the engine look cool, but price and tuning hassle will keep them out of my hands, at least for now.
Hey, I just noticed that you're local (I'm in Chaska). Give me a shout if you run into any snags. I installed Al Kosmal's Triumph ITB kit on my car with MS2 and really like it. If you decide to go with the "clean look" and your airbox is in good shape I have a totally destroyed CIS airbox from my car. It would be better to cut that up than mess up an airbox that's still in good shape. Otherwise have you considered a Carrera manifold? They look pretty good and bolt up with adapters that you can find online. If you want to see how that looks on your motor I also have one that you could test fit.
Old 08-20-2017, 09:12 AM
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Originally Posted by wiggle_puppy View Post
Hey, I just noticed that you're local (I'm in Chaska). Give me a shout if you run into any snags. I installed Al Kosmal's Triumph ITB kit on my car with MS2 and really like it. If you decide to go with the "clean look" and your airbox is in good shape I have a totally destroyed CIS airbox from my car. It would be better to cut that up than mess up an airbox that's still in good shape. Otherwise have you considered a Carrera manifold? They look pretty good and bolt up with adapters that you can find online. If you want to see how that looks on your motor I also have one that you could test fit.
Hi Wiggle,

Thanks for the offer, I have my bad air box too, but I never really thought about the Carrera manifold, remember vaguely a mention of it, I'll look into it.

Any chance you can weld an O2 bung on? I need to get that done, but car is running so bad that I don't dare try and bring it somewhere and removing the exhaust could have its own issues, so I was going to hire a mobile weld outfit.

Best,
Rutager
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Old 08-20-2017, 11:12 AM
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Are you going to go with MS ignition as well or just fuel? Is it up gradable later on?
Old 08-20-2017, 11:59 AM
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So I did a quick investigation on the Carrera intake and it appears that used they go around $500 or so and the adapters over $200.

Since I've spread a lot of grit for traction on the slippery slope, I'll go back to my original plan! Thanks for the info, always good to check options.
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Old 08-20-2017, 12:01 PM
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Following!

Are you going to go with MS ignition as well or just fuel? Is it up gradable later on?
Just going with fuel to start, I don't think ignition gives as much improvement for the cost. I understand that the Megasquirt can be upgraded to ignition at a later date.
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Old 08-20-2017, 12:03 PM
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You'll be very happy with your Bitz EFI conversion. I personally like the "clean look", and I believe part of the very improved throttle response is from deleting the whole metering plate system.

Conversion is easy with engine in car. Simply unbolt all intake runners and lift the whole thing out. BUT: Be carefull when you pull the intake runners - there seems to be a very strong gravitational pull towards the cylinders for washers and such.......
Old 08-20-2017, 12:11 PM
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Quick note about the O2 bung; car suddenly went lean on me after last drive and backfires out the tailpipe, so I won't drive it somewhere, I don't know how to weld and don't have any friends that do either.

So, two options: one take off exchanger and bring it somewhere or hire a mobile welder to stop over. I'm sure bringing the exchanger to a muffler shop for welding would be super cheap- breaking an exhaust stud would get expensive and add extra complexity to the project, so I think paying a company to do it in place is the smart option- probably be a couple hundred bucks, but in my case the better way to go.

Any MN Pelicans that can weld and want to make some money, I'm in Saint Paul near Maplewood!
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Old 08-20-2017, 12:14 PM
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