930 EFI Conversion in process

[beepbeep]

Originally posted by Jim2
Man Beepbeep, slow down, I've barely washed the grime off my hands! The methanol concept has crossed my mind (hehehe) but I don't think the system supports alternate maps. However since its just a overall ratio change the tuning knob would take care of this I supose.

I'm not talking about methanol. Methanol has nothing to do with E85. Methanol is aggressive on engine and never used on street. I'm talking about ethanol, as booze. E85 contains 85% ethanol, it's stochiometric ratio is around 9.75:1 and is found on many gas pumps. It's usualy made of corn.

All this about E85 was just a hint. Many turbo tweekers in Sweden switched over to E85 as it supports more boost and is less knock-prone.

Good luck! You are doing great job!

[89turbocabmike]

Nice work Jim, some very impressive fab work. What a great solution for the fuel fitting conversion, as I may need to swap my cis motor in for smog testing. Nice welding on that air filter mount too, looking forward to the intercooler build-up. I'm also looking forward to your impressions of the SDS ecu for our application and what if any major limitations you find as tuning progresses. Thanks for sharing.

[hobieboy]

Originally posted by Jim2
Hobbieboy, the SDS temp sensor only works during warm up. How does yours work?

Jim [/B]

I'm using Megasquirt. It is pretty much the same - mainly for warmup & initial start enrichment though it does use that for additional accel enrichment if wanted.

My beef about the passenger location is: the MS has a CLT/temp sensor table for warmup. In my case, the temp can fluctuate by 50 degF depending on whether I'm sitting in traffic or moving, so it somewhat affects my overall fueling as warmup (i.e. fuel enrichment in %) sometimes kicks-in if I'm moving too fast

[Jim2]

Hobbieboy, now I understand what's happening, the sensor is getting over-cooled while driving... I'll keep an eye on my sensor tonight when I drive it. I guess this means we might have to move these things to a location with more mass. Either the cam box or crankcase might work. Thanks for the heads up, this really could have messed with me if I didn't know to watch it.

Beep, I overlooked this when I replied, I'm aware that this fuel (at Canadian Mohawk dealers) is ethanol based, not methanol, but what does M85 refer to? Is it the same?

Jim

[RarlyL8]

M85 is a blend of 85% Ethanol and 15% gasoline.
I have some reservations about using it in our older cars. Ethanol can be very corosive.

[Jeff Alton]

Jim, this install is amazing!! You are doing a really first class job.

Mohawk gas scares me here too, but it is one of the many "tricks" I have used to help get a car through aircare here.


Cheers

[hobieboy]

Jim,
Please keep me (us) posted on your progress - great thread so far! And I would love to hear where will you end up leaving the temp sensor. I'm pondering that too.

Maybe I can soon start a similar thread on my rebuild; though definitely won't be able to beat your great pics

[89turbocabmike]

Jim, what size injectors are you using?

[Rob 930]

Jim,

I just caught up with your thread. Very impressive. I wish I had your fabricating skills and tools. I can do lots myself, but if the fab work involves much more than stock aluminum, a die grinder, a drill, and a file, I'm hunting (and paying) for help.

I've just done EFI on my 78 930 (similar, with Carrera manifolds). It's running and dyno-tuned, with a DTA ECU. I've installed an FJO WBO2 controller and gauge, so I can watch AFRs from the cockpit. It also communicates with the ECU and can be logged. It's a great product and a Canadian company; you might check them out, eh?

A couple things. I'm interested in why you made bakelite spacers to go under the Carrera manifolds. You're using 930 heads, right? What intake port size do you have? My 930 heads were ported to match the manifolds (about 41 mm) and I was able to use the factory bakelite spacers, which are about 5/16 in thick or so. Could you have used the factory spacers too? We made sure the heads were ported such that the injectors had proper sized pockets around them. And there was plenty of gasket sealing area left -- with no need to do any welding, as I've seen some people do. My concern is that you may not want to elevate the Carrera manifolds too much, or you'll diminish the space for an intercooler.

Also, for CLT, I use a Bosch sensor in an oil passage. More specifically, I put it in the thermostat cover for the engine oil cooler (which I removed), but there are other locations that work as well. I would think that to use oil as your measured medium may work better and fluctuate less with heat soak and such.

Very nice job. I'll be interested to hear your driving impressions and maybe hear about dyno numbers.

Rob

[Jim2]

Hi all,

Really good news. I took the car out last night and put about 30 miles on it. With the default numbers SDS put in the computer the car ran surprisingly well, and data logging showed that I really only needed to address the mixture under 2000 rpm. The top end, up to about 5500 at .7 bar was in the high 13s AFR. I only did a couple rips, and now I'll write down the paulse values before I go changing them so I can recover if I screw up. I want to fatten up the top a little, and I still need to lean out the bottom more, but the car almost drives perfect!

Ignition timing is pulled back a little, and it needs more advance in the bottom end to match the characteristics of the distributer. It has quite a noticable midrange torque improvement, and I anticpate that it will improve more as I tweak the mixture and timing.

It took me a while to understand the programmer because I don't grasp things like this easily, I really prefer wrenches and gears. It's a miracle that I can even post this text!

To answer a some questions which were posted, the injecters are only 42lb. They are not bigger because I'm conservative. I recall calculating that they will support near 400 hp at 85% duty cycle.

The temp sender is seeing heat soakback exactly per hobieboys advice. I'll trim the numbers back so it finishes the warm up cycle at about 50c. I think that by the time sensor sees 50c the heads are up to a decent operating temp.

I also noticed a significant decrease in EGT. I'd estimate 100F lower than before. Surprising, and not sure why yet since I my timing is still retarded relative to the distributer.

Rob 930, I did not have any Carerra isolators nor have I had the oportunity to see a Carerra head (or isolator for that matter). These isolators were the only way I could mate the manifold up short of porting the heads. Perhaps the work could have been reduced, but I read a large number of posts about the need for custom isolators, so I went ahead and built them. I don't know if my ports are stock, but they measure exactly 1.5" dia, nominally the same as my Carerra intake. Is this the stock 930 dia?

I also wanted isolators to reduce heat soakback into the injectors, but it's just a guess that soakback would be an issue. Even with the isolators the manifolds are still about 1" below the top of the fan, and with the added 5/8" the manifolds clear the turbo oil feed line.

Generally if I can build a small part in a short period of time, I'll do this as opposed to driving to the dealer, or ordering, getting robbed when the bill arrives... hence, isolators, intake gaskets, intake nuts, studs etc.

Took the car out to grab a starbucks tonight and it ran well, but I can identify some improvements that I'll do this weekend.

Jim

[89turbocabmike]

This is the bestest thread

Jim I noticed in my SDS research that your crank pick-up is similar to other SDS project vehicles, where did you find how to make it and just how difficult would it be without a mill-drill?

In case you haven't checked it out, innovate motorsports has some great tuning information.

http://www.innovatemotorsports.com/resources.php

[hobieboy]

Jim,
Glad to hear everything went well. I would be interested in knowing what your AFR in the top ends up as I'm also trying to map that right now.

Going to the track tomorrow so should give me some open space to map those

[Rob 930]

Originally posted by Jim2

Rob 930, I did not have any Carerra isolators nor have I had the oportunity to see a Carerra head (or isolator for that matter). These isolators were the only way I could mate the manifold up short of porting the heads. Perhaps the work could have been reduced, but I read a large number of posts about the need for custom isolators, so I went ahead and built them. I don't know if my ports are stock, but they measure exactly 1.5" dia, nominally the same as my Carerra intake. Is this the stock 930 dia?

I also wanted isolators to reduce heat soakback into the injectors, but it's just a guess that soakback would be an issue. Even with the isolators the manifolds are still about 1" below the top of the fan, and with the added 5/8" the manifolds clear the turbo oil feed line.

Generally if I can build a small part in a short period of time, I'll do this as opposed to driving to the dealer, or ordering, getting robbed when the bill arrives... hence, isolators, intake gaskets, intake nuts, studs etc.

Jim

Jim,

I don't recall the cost of the isolators from Porsche, but they were not bad -- I think on the order of $5.00 each. I have never read a post that suggested custom isolators needed to be made; I'm curious how you came to understand that. Of course, it's best to match the manifolds to the heads, which may require porting. I agree that having isolators decreases the heat flux to the injectors, which is a good thing (that's why I never liked the aluminum injector block idea for CIS manifolds, though others have had success with them). But since the factory used the "thin" isolators of approximately 5/16 in. thickness on the Carrera manifold, I'm guessing that was sufficient, and it's what I went with. Doing so allows the use of stock Carrera intake manifold studs, nuts and gaskets from Porsche as well (which was easy and surprsingly inexpensive). I'm sure your solution works fine and there's probably no reason to change, but I though I'd detail this for the benefit of others who might want to know that there's another solution that also works well and doesn't require so much fabrication (which, unlike you, I always try to avoid!).

The big deal in my mind (other than matching port size) is minimizing the height of the manifold if you're planning to use a full bay IC -- especially if you're using a stock tail. There's precious little room (vertically) to squeeze in an IC. I have an unusually thick core (4.5 in), and if my manifold had been any higher (even 1/4 in.), I would have had to change plans and go with a different tail (or use a different IC).

You said your intake ports are 1.5 in dia. That's equivalent to 38 mm. Factory 930 heads came stock with 32 mm intake ports, so your ports must have been opened up. Factory Carrera manifolds are 40.5 mm. If you're going to use a Carrera manifold directly on 930 heads, it really requires the intake ports be opened up to match. But with your spacers, you may have found a way to smoothly transition from 38 mm to 40.5 mm, which is a relatively small change. There's no way you can go from 32 to 40.5 mm with a thin spacer; porting is required. Then there's the whole debate about just how much difference it really makes if you *don't* match port and you just bolt on the Carrera manifolds. To my knowledge, theory may frown on this, but practically speaking, it may work out okay if you're not trying to extract every last horsepower. I know someone who did this ("Dean") with no ill effects that he could definitively attribute to the step in the intake stream.

Rob

[beepbeep]

[OT]
Today I was helping a guy who had a turbo-converted BMW 635 with KKK K27. C/R was around 7.0:1 (machined pistons). For what it's worth, engine is quite similar to 930 engine: two valves per cylinder, six cylinders, 3.5L displacement, K27 turbo. One big difference is that he runs it on E85.

He tried to map it himself using narrow-band lambda and expirienced what he called "hesitation" under transition from zero boost to full boost.

We did few logging pulls on a highway and found out that he was running a labmda ratio equivalent to gasoline 15.6:1 AFR when boost started to build up.

The engine never missed the beat, never protested, never did a single ping...it just lost some of power @ 0.5 bar boost and 15:1 AFR... We played with ignition back and forward, had it at 32 degrees of advance just for fun. Nothing...not a single ping. We could chase best MBEP best we wanted...

That's the good thing with E85. It's wickedly knock-resistant!

Just to show I'm not lying, here is a log from before/after pulls while we tried to bring down AFR's into acceptable region. (EFI was of some awkward sort where you didn't have graphical interface but just a small box where you entered compensation table's with two butons, up and down. Like SDS but much more primitive). I didn't have so much time so we just adjusted AFR's on initial boost buildup and called it a day.

If we tried this stunt with premium unleaded we would be spitting out the pistons trough the tailpipe:



[/OT]

[Jim2]

Turbocabmike, the spacer I put under the crank pickup ended up 5/16" thick (I started with 3/8" stock) It just as easily could have been made from layers of 1/8" and 1/16". The spacer thickness is dependant on how far the magnets protrude out of the pulley, and SDS gives a pretty wide tolerance. You definately could build the spacer with nothing more than a hacksaw, a file, and a hand drill. My method requires a countersink and some matching bolts and a tap - Homedepot has all this stuff.

Jim

[ianc]

A thoroughly enjoyable thread with some great fabrication work. Consider me subscribed and waiting to hear more!

ianc

[aseem]

Great writeup. Can't wait to see the engine with a new IC.

Btw, what is MBEP??

[Jim2]

Hi all, aseem, the intercooler will be a little different than the conventional arrangement. I have all the bits sitting here, but I'm out of time and need recharge before forging ahead.

BMEP which Beep is referring to is short for Brake Mean Effective Pressure. It's been a long time since I studied the subject (about 20yrs) and I've forgotten the specifics. It's something like the cylinder pressure developed just after firing the charge when the pressure is at it's maximum. There are a number of variables which influence BMEP, such as volumetric efficiency and timing of the combustion.

We need someone with more depth on the subject to chime in. You out there Beepbeep?

Jim

[Jim2]

Hi all, here is an update on my EFI project.

I finally got a break from work this last week and spent some time on my car.

I needed to move my engine temp sensor. In it's previous location it was getting cooling influence from the fan. Hobbieboy mentioned this several posts ago and it was immediately apparent several weeks ago when I first drove the car after finishing the EFI conversion.

For the new temp sender location I made a small bracked to clamp the sender to the edge of a cylinder head cooling fin. The temp sender is only used for enrichment during warm up, and now it sees operating temps consistently above "warm up cut out" temp. Interestingly, on an average 72 degree day the cooling fin only reaches 152F at cruise speeds.





I had been noticing that my O2 readings were very sluggish so I bought a new sensor which solved the issue. This was likely due to contamination from race gas used when the car is on the track. Also the old sensor no longer showed any readings in the 13:1 range no matter how rich I adjusted the mixture. With the new sender I needed to lean out the mixture which resulted in an increase in performance. I had noticed the tail pipe was black with soot, but the old send kept saying I was in the high 13s.

I wanted to achieve a misture of about 12:1 under load which is beyond the ability of a narrow band O2 sensor, so I mapped the mixture to 14.5:1 then calculated the enrichment needed to obtain 12:1 and changed the numbers in the programmer. The car runs strong now though the entire powerband.

I managed to borrow a wideband O2 meter system which I'll install in the next couple days to see how accureate (or out to lunch) I was with the narrow band - should be interesting to see.

Gratuitious pic shod in street attire:



A shot at the track prior to EFI

[ianc]

Very nice looking bracket, but it's gonna be a beeyotch to get at if it mucks up...

ianc