924Board.org

[-nick]

Yep, threaded a Bosch filter (I can get the p/n if you need it) directly on to the feeding hard line under the brake m/c. It will be a pain to replace no doubt, but it's a tidy solution

The filter exit side is more interesting - the original fuel supply line that connects to the CIS fuel dizzy via a banjo bolt: if you strip the rubber line off the banjo'ed steel part at the end, you're left with a 5/16" hose barb. I used that to banjo to the filter, then used some EFI fuel hose and a good hose clamp.

For the return line, I bent the metal line under the brake booster so that it is directed straight up and comes out to the right of the booster on the firewall. Back to the CIS lines - the return line that comes off the fuel dizzy and connects to the metal lines on top of the passenger fender: if you strip the rubber line off where the lines connect, you'll have a 1/4" hose barb that will thread onto the feed line at the brake booster.

If you actually have access to a place that carries these fittings then you won't have to pillage the old CIS rubber lines. But they're an easy solution.

I'll try to get some updated pics up at some point. I re-routed the fuel and vacuum lines to make life much easier.

Good luck!
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1980 931S
15psi boost, MS-II, EDIS, 951 IC, custom intake, Ford 5.0L throttle body, Forge BOV, WB o2, G31 w/LSD, 964 wheels, 968 rear sway, Bilsteins, 200# Welt. springs. A laptop, and a partridge in a pear tree.
1991 964 C4 Cabriolet

[pockygt]

Please tell me who you used for all this welding and fabbing. I'm -kinda- in your neighborhood, and I'd prefer to use a known good place.

I love your set up, I want to make mine more or less just like it. How much did the custom plenum set you back?

again, great job!
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1981 924 Turbo (931)

[vemser]

Injectors

I'm using 42lb/hr Bosch high-impedance injectors. Low-imp injectors
require a little more hardware work to the MegaSquirt board.

Endwrench supplied injector cups that screw in place of the stock
CIS injector cups. The injectors & fuel rail snapped right in with
no leaks or problems.

-------------------------------------
Can you show picture or injectors part number?

[-nick]

Hey folks,
I've made quite a few changes and learned a good bit more while I've been tuning.

First, the 42lb/hr (440cc) injectors seem to only be good to about 230 fwhp at 3bar fuel pressure. At that point I was bouncing off a duty cycle in the high 80% range, which is too high. I've since moved up to 750cc injectors (www.rceng.com #SH4-0750). I'm running very rich at idle at the moment, but I've barely begun to tune the new injectors in. They should flow more fuel than I'll ever need. To note is that higher fuel pressure gives better atomization. 3.0bar is probably where you want to stay (for 1atm / base pressure settings). I had idle issues with the big injectors and trying 2.0bar.

A nice factoid: the injector o-ring seals for a Mitsu Eclipse work perfectly on Bosch injectors and every local auto parts shop has them.

Also, I've been battling a heat soak problem - after shutting the car down while hot, then starting it up from anywhere between 10 minutes to an hour or more later, the air intake temp sensor would heat soak and report higher temps than it was actually getting. So the ECU squirts less fuel and it runs lean until the sensor equals out to the real air temp. To partially solve this, I moved the sensor to the exit side of the intercooler. This seems to have helped so far. The sensor was at the back of the intake up against the firewall - not a good spot! The MS ecu has a table to change the amount of fuel compensation as a function of intake temp that I'll mess around with next. Still not a great solution. I really need something that runs a clock so that it knows how long it's been since a restart. No such ECU feature yet.

If I were able to do it all over again I would have mounted the 951 IC in the nose. Being inside the engine compartment is not a great spot, although it was an easy place to put it. I might move it under the nose yet. This would open a large space for the air filter, which is likely an air restriction at the moment because of its size.

The intake/aluminum welding was all done at Roger's Radiator in Medford, MA. Their welds were really very good. Still, not cheap. And the plenum/throttle body needs to be repositioned to avoid having the hose off the TB getting squished. It doesn't really effect anything, it's just annoying and I'll probably have to replace that intake hose every so often.

I hope all this helps! I'm sure I'll be ironing out more quirks as I go along. Once I get some time and the temperature drops below 90F (!) I'll start committing to tuning and inching the boost up higher. It pulls extremely well as it is at ~13psi.

PS- if anyone wants the high-impedance 440cc injectors I was using then make me an offer
_________________
1980 931S
15psi boost, MS-II, EDIS, 951 IC, custom intake, Ford 5.0L throttle body, Forge BOV, WB o2, G31 w/LSD, 964 wheels, 968 rear sway, Bilsteins, 200# Welt. springs. A laptop, and a partridge in a pear tree.
1991 964 C4 Cabriolet