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By Crumpler
#26760
Ok gentlemen. DE season is over and I am going back in to the garage.

Specs are as follows:

Procharger P-1SC-1 (Standard Drive!) is going on with non-helical gears.
Goal is low boost system 4-6 boost, with procharger bullet BOV to prevent compressor surge.
Currently stock ECU computers.
Currently adjustable FMU.
Currently 24 lb. four hole injectors.
Currently barrel air to water intercooler.
Wideband in cabin.
Currently 6.5 inch crank pulley with 4.75 inch blower pulley.

How does the collective feel about aftermarket knock detection? I was considering a basic signal light kit.
I have a pro doing the final tune, but I would like a safe ballpark as I attempt to set FMU, etc. The long game is either sharktuner or VEMS system.

There seem to be a few options out there. But what’s the likelihood they will give me accurate results?
The Link kit has a self calibration for an engine’s normal noise range first, which sounded appealing on paper, but also got the impression that once a knock event is detected it just stays on until you shut off.
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By Crumpler
#26774
Excellent, many thanks.
I don’t think it would hurt anyone to have some insurance here for knock events. My concern was having to interpret false positives or negatives with the sensor.
There was some chatter on the other channel about the S3 pistons being noisy to begin with, or maybe the opposite— I stopped listening;)
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By Crumpler
#26789
93 always and forever :)
You know unofficial accounts suggest that I vent crankcase to atmosphere... which probably helps octane further.
Shifted liked this
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By worf
#26879
Have you yanked on Porken?

If I was boosting an S3, I’d see if Ken could hook me up with an EZF prom that would pull timing based upon one of the unused pins going high or low (or maybe repurpose existing input) that ate from external knock detection.

I’ve a dim memory that he did something like that already.
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By Crumpler
#26923
worf wrote: Tue Oct 20, 2020 9:11 pm Have you yanked on Porken?

If I was boosting an S3, I’d see if Ken could hook me up with an EZF prom that would pull timing based upon one of the unused pins going high or low (or maybe repurpose existing input) that ate from external knock detection.

I’ve a dim memory that he did something like that already.
Dave that’s a crackerjack idea.
I have grown so used to not expecting much from the stock computers, it didn’t occur to be that I could utilize them for anything.
I haven’t yanked on Ken since I asked for any black op chips going into this last DE without the planned boost;)
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By Crumpler
#27404
Calculating for fuel injectors tonight.
I've got the top end torn down to place the knock sensor and this seemed like the time to change from the 24 lbs. if I was going to.
So far the various website spreadsheets recommend 30-32 lbs/hr
Based on:
estimated hp at crank (picked 400)
8 cyl
80-85% duty cycle
BSFC 0.55
55 psi fuel pressure ('87 FPR)

I had kicked around on old threads and really never found any consistency with injectors used for 928 SC projects.
Of the 30 lb choices, I found Accel, Bosch 0280155759, or various Ford examples. Most required O-rings sourced to fit.
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By worf
#27415
Crumpler wrote: Thu Oct 22, 2020 8:39 pm Calculating for fuel injectors tonight.
I've got the top end torn down to place the knock sensor and this seemed like the time to change from the 24 lbs. if I was going to.
So far the various website spreadsheets recommend 30-32 lbs/hr
Based on:
estimated hp at crank (picked 400)
8 cyl
80-85% duty cycle
BSFC 0.55
55 psi fuel pressure ('87 FPR)

I had kicked around on old threads and really never found any consistency with injectors used for 928 SC projects.
Of the 30 lb choices, I found Accel, Bosch 0280155759, or various Ford examples. Most required O-rings sourced to fit.
FWIW, my twin screw uses Bosch 30# injectors.

If you don't know already: Whatever injectors you get, do your best to get their opening time (latency) so as to poke that value into the ST.
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By Crumpler
#27597
Hey Dave, thanks for the feedback. I didn’t realize you your sitting on a twin screw variant. Was it a DR kit?
I found Ken BTW, he said while pulling timing was possible in theory for the S3, but not practical, I’m paraphrasing:).


Chris, that’s excellent data again thank you, that’s a pretty convincing story. I will see how it goes with the 24’s first.

Now here’s today’s dog exploratory surgery:
Two pair of creepy, semi-mummified laytex gloves, and a chunk of glass.
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By Crumpler
#27709
Yes, that's better. I was concerned that you had not seen the mummified creepy hands picture yet.
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By SeanR
#27778
For injectors I'm using these on everything that's boosted.

https://www.racetronix.biz/p/63-lb-hr-s ... t/fi114961

You can save some money and not get the flow matched set as it's really not necessary.
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By Crumpler
#27893
Nah, my job might smell worse but it is just like anyone else’s. The longer you do it the more comfortable you are at it.


Ok, thanks guys, I will check out the injector choices.
What are the real specs for the o rings. With calipers I get 13mm OD on my current ones, top and bottom. Does that sound right?

Also another curve ball, new blower orientation doesn’t work at old location. I would have to further wikiup radiator hoses and also choke down the inlet more. That’s just too problematic. I’m going to look at the old A/C location and see what I can come up with.
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By Crumpler
#30348
SC is set up at new position . Some progress.
Bracket work was just as tedious the third time.
Multiple advantages at the old A/C position, at least for the S3 configuration. I think IMO did this spot for his SC back in the day.
Tensioner placed.
More to come.
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By Crumpler
#32665
Not the most productive weekend ever, but did get top end assembled and set BOV.
By rights I think the BOV should be as close to the throttle plate as possible, but in S3 land that turns into just after blower, I am hopeful it won’t make a big difference.
It’s a procharger BOV. There are no published specs on spring rates, maybe to protect the secret sauce. My assumption would be it’s compatible since it’s a SC company.
It’s also not the biggest vacuum signal line going into it, but we will see.
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By Crumpler
#33301
Shifted wrote: Tue Nov 10, 2020 7:36 am The two main reasons why most people recommend putting the BOV close to the throttle plate are:

1) So that the pressure is relieved from the throttle body as soon as possible. This is more about reducing pressures that can blow something apart (e.g. a clamped on silicone connection) and allowing a smoother return to idle or lower RPM.

2) So that as little air as possible is lost and pressure can be built up faster. This is focused on having faster boost response when downshifting or coming off of and then back onto the throttle.

I think that these are theories that have diminishing returns the lower the pressure. Above 15 psi, and definitely in the 25+ range, they probably make a noticeable difference when transitioning to/from boost. At your pressure levels, it might be demonstrable, but I doubt that you'll notice a difference most of the time.

Your vacuum signal line looks like a decent size from the photo. What size is the line?
Ok, that makes sense to me.
On calipers, the OD of the line is 8mm. Looks to be next size up from the port sizes on the TB.
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By Crumpler
#37208
I’ve got some time this week to get in the garage.
God, I’m starting to sound like Jerry.
Anyway, covid silver lining: same amount of food and the in-laws cancelled their Thanksgiving visit!

Had to relocate the intercooler pump to under the passenger fender. Tedious.

The intercooler set up is a challenge for 85/86.
Never got any hope of buying a custom Murf. Unit or that stage two number that Carl had. So I found a barrel intercooler that would fit.
My concern is the core size 4x8, was the biggest I could get in there and it seems limited.
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By Crumpler
#37268
Thanks Chris, yeah while the plan is low boost system, having it out on the track without an intercooler made me nervous.

There is a knock sensor installed in the forward position. It will be wired to a signal light in the cabin. Hopefully it will give me diagnostic readings.
I had a distant plan of both air temp and coolant temp gauges, but nothing in the pipeline yet.
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By Crumpler
#45062
Tighter belt and better tensioner set up after another revision.
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Ran and idles well up to temperature.
But I noticed some fluid at number five cylinder area.
Initially I thought it was from the water bridge but on a paper towel it’s gas. So I assume an upper o-ring issue on that injector. So there’s that.
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By Crumpler
#45286
Notice the calming green knock light.
It’s saying “you are ok Dave, even though you don’t really know what you are doing, I am not detonating. Therefore, you don’t have to poop in your pants.”
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By Crumpler
#51968
Moving slowly towards the finished project.

Fuel leak on number five injector was a pinched o ring.
Placed a coolant temp gauge in the cabin.

Took it out today for a drive.
Ran strong, good temps, no knocks detected.
It always feels fast after not driving it for months.
I didn’t see boost but I didn’t push it to WOT either.
I did check function of BOV afterwards.
It does move with heavy throttle.
On Mightyvac it closes at 3 in Hg
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By Crumpler
#52992
Took the car out today for some WOT runs.
Pushing it harder I can be more objective:
Definitely gains, most notable at high end.

I was telling Shifted today that I really should have put the vacuum/boost gauge in a better location. Trying to rubberneck readings at WOT is problematic.
Real data so far looks like boost starting at 4000 rpm.
Two pounds was the highest number I saw.
AFR at WOT was 11.2 pretty consistently.
It was about 40 degrees outside.
No knock events detected.

My next move is to experiment with some smaller pulley sizes for the blower. Currently it’s a 4.75 which was on the bigger and conservative side.
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By Crumpler
#55867
Ok gentlemen, I think we are close. Finally.
With the smaller 4.0 pulley the results were much different car.
A little compressor surge even with the BOV but I will take it.
Boost starts 3200-4000 rpm depending on load.
It’s probably as much car as I need now.

At three pounds of boost I start losing the back end, I really couldn’t get to WOT. I’ve got summer performance tires on and it’s about 35 degrees outside.

One tentative knock event seen on the light. Got an orange flicker in third.
Thank you all for helping me along the way.
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By worf
#55873
Crumpler wrote: Sun Jan 31, 2021 2:41 pm One tentative knock event seen on the light. Got an orange flicker in third.
Thank you all for helping me along the way.
This is where being able to use the ST for tip-in enrichment can be helpful (if the knocks are occurring on transition to more throttle.)
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By Crumpler
#61193
Someone else will have to follow this thread if Shifted is gone! One of you cowboys better step up ;)

At the time of the SC install I was just trying to find room, the inlet and filter were an afterthought.
On this set up the inlet is facing the rear, on the lower block area. About the level of the lower control arm, with ten or so inches ahead of the exhaust manifold. Not ideal.

Option one was run a pipe either back or out to the side fender. Clearance was biggest concern there and I wasn’t prepared to do anything to the crossmember.

Option two was to run something up and around forward to traditional area in engine bay or better yet to the scoop where the first set up was.
This was going to be pretty convoluted and also require heavy fabrication of either an inlet box or a three inch pipe bent essentially 320 degrees.

Option three was an 90 degree elbow down away from heat with a mushroom filter. The color is grotesque but the clearance is ok. I’m going to source a wet sock for it if I can.
And no, I wasn’t the guy that took a chunk out of the pan :grimacing:
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By Crumpler
#61246
SeanR wrote: Sun Feb 21, 2021 2:36 pm Can't you clock the intake side of the SC to a few different positions?
It’s tight man.
I could but the limiting factor is still the back or inlet side. Stock tensioner sits right there so there’s only one path to run pipe up and over SC and under cap and rotor.
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By Crumpler
#62157
Installed an air flow straightener today (10:1)
Which will be after two 90 bends and before MAF sensor.
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By worf
#62163
Crumpler wrote: Sun Feb 21, 2021 2:27 pm Someone else will have to follow this thread if Shifted is gone! One of you cowboys better step up ;)
I'm following. But fabrication is not my forte.
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By Crumpler
#62188
worf wrote: Wed Feb 24, 2021 4:03 pm
Crumpler wrote: Sun Feb 21, 2021 2:27 pm Someone else will have to follow this thread if Shifted is gone! One of you cowboys better step up ;)
I'm following. But fabrication is not my forte.
All you have to do Dave is hit the giant red button if you see me going off the rails;)
amdavid wrote: Wed Feb 24, 2021 4:49 pm I'm following because "I like".
And what’s not to like!
A project spawned in vengeance (to wipe the smug off a few mugs at the track), implemented by someone locked in garage with a very small amount of functional knowledge and some disposable income, and based on a couple of pictures he saw once. What could go wrong?
;)
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By Crumpler
#62233
......It shall be so!

I don’t think I covered the cooling mods.
Because it’s a forced air track build I did everything I could to cool it.
I pulled the MY 85-86 radiator and replaced with a non-oil cooler radiator for a little more volume.

Hood scoop is a reproduction off a late 924 turbo.

Low temp T-stat.

I have larger AN fittings and lines running to a ten row setrab cooler up front for more oil cooling. No pressure changes noted BTW.

The stock belt vicious fan is long gone. Two eight inch electric fans behind radiator that run off temp sensor in upper radiator hose.
Additional 16 inch fan on front of the radiator, which is switched in cabin. Coolant temp gauge in cabin as well.
Edit: forgot that I deleted heater valve, using the heater core as a secondary radiator with blower on, how’s that for dedication. I will be sweating.

The intercooler: just a bitch to place in the S3 engine bay with the damn pipe organ. Murf and I believe Carl made or had made dedicated units, but I have up trying to procure one after a few months.

I came up with a barrel, air to water, intercooler that fit, but the core had to be smaller. The work around was a larger heat exchanger up front and then secondary heat sinks in the coolant line circuit. The set up seems to work well so far. But not track proven.

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Last edited by Crumpler on Wed Feb 24, 2021 9:07 pm, edited 1 time in total.
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By Rdon
#62234
Crumpler, there’s a used Murf 928 supercharger kit for sale on PelicanParts. No supercharger included but he claims all other parts are there. Don’t know if any of it would help you out but have a look if you’re interested.

http://forums.pelicanparts.com/porsche- ... r-kit.html
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By Crumpler
#62244
Rdon thanks for following and thanks for the link!
It appears to be an 87 plus kit? The intercooler doesn’t fit unfortunately.
I’ve never seen a Murf kit up close, very interesting.
I trying to figure this part out. It looks like the box I was going to fabricate for the blower inlet, but the fittings on the side are throwing me. Second intercooler?
Does anyone know?
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By Tony
#62316
Where did you get the "air flow" straighter?

I got two of mine from the Kitchen aisle in target. :rockon: Was thinking of adding a "proper" one....although, the two apple slicers did make a marked difference in the way my car ran. I had a very slight hesitation as i would accelerate. They cured it.


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