karl ruiter

I have no idea where it is, but I will have a look when I have a chance. Hacker knows some stuff for sure, and I am sure he has valid points. However, I have not heard that there are big piles of L-jet cars that blew up because of Carl's kits. As opposed to his 32 valve stroker builds. Many of those were NFG and you heard about it here.

PorKen

Now that I have plenty of power at idle (with Roger's Bad *** Uber alternator), I have spare amps for an intercooler pump

Great information on that Jon Bond page.

"Bypass /blow off valve is not required unless over 9psi, however, we recommend one for longer belt life."

I moved the BOV on my 928 MS 32V Raptor kit (3~4 psi boost) close to the throttle body versus next to the supercharger as an experiment. Moving the BOV vastly improved throttle response. Plus, before this change, each time the automatic shifted there was an unpleasant lag after the BOV dumped boost. Now shifts are crisp.

(The Australian made Raptor is internally belt driven. I sent mine back for a rebuild and it was upgraded to a 30mm wide belt and billet impeller.)

LyndonJames

AMAZING!!!! What kit did you use or did you just piece out yourself?

hacker-pschorr

Valid point, but you also don't really see a slew of people claiming their L-Jet (or CIS) 928 worked well with the kit either. I can recall a couple folks I talked to with said kit only making 2-3psi at the very top end of the RPM range. Some others their car ran so bad they simply stopped driving it or took the kit off.
The "tuning" method was "run super rich to keep the charge cool" which in theory can work, especially at very low boost levels. My favorite part was using hotter spark plugs to burn off all the oil from the excessive blow-by.

I can't say I ever noticed such lag, but then again never really spent much time driving kits with much less than 11psi. Also with an intercooler you really want the BOV before the cooler. Different BOV's can make a big difference too though.

PorKen

It was a 928 Motorsports stage one (non-intercooled) kit for 85-95 32V, installed for the PO by a shop. It has taken a lot of work to make it perform acceptably. Mostly due to the bad installation*, but also due to limitations of the kit. (I should make a separate thread about it.)


*EG. BOV connected to the vacuum line to the flappy

PorKen

When you have less than 4" you have to be more careful about keeping it in!

Since I don't have an intercooler, I am trying out this Goldbergian contraption to dump boost when the intake manifold gets too hot. If the AC is on, at 87C/190F the intake fan switch* activates a solenoid valve to switch the BOV and FMU from manifold to stored vacuum until the intake cools to 82C/180F. (A diode isolates the fan trigger from the compressor clutch ground. I will probably wire up a valet/winter switch as well.)

Of course, now the weather has gone back to temps in the 80's F, where it was 90-100F for over a week, so it may be a while before it gets tested.



*92860621700 fan switch for $29 on Amazon, B00DZLWCDO - my old one was stuck on - also used on S3s

karl ruiter

Hey Ken
Do you want an intercooler, or are you happy with your solution? I think I have one.

PorKen

Were my hints that loud?

That would be great if you have one! I have yet to see if my gizmo works but I could always use cooler air.

karl ruiter

I'll look around and see if I can find my L jet manual and my intercooler.

hacker-pschorr

touché


I know you know what you are doing and that's an interesting experiment, but holy wow that's hot. I get nervous when a boosted car is 30-40F hotter than ambient at full boost.

One thing though, is air temp sensor speed. Most are really slow. Years ago Mike (Z) installed like a dozen different such sensors in a big PVC pipe and wired them up, turned on a hair dryer to measure how fast they responded. Most took forever while some were instantaneous. Back then the fastest ones outside of motorsports / milspec parts were the VW units from the 1.8T engine.

Crumpler

I have some data to throw in for a non intercooler set up.
My (unconventional) 12 pounds of boost will hit around 80C/176F air temp after full boost. I must have put in a faster sensor at some point because the numbers go back down baseline quickly (maybe 20 seconds). Running temps are usually in the 120’sF if ambient is 80’s F.

I feel like I did some research and wasn’t as freaked out when I some turbo guys running much higher. But probably apples to oranges.

Edit, forgot to say I’m also pulling timing with air temps over 80C.

Superedit: Ken I’m glad to see you are bringing FMU’s back in style

karl ruiter

Ha! Look what I found! Installation manuals for both the FAST kit and Carl's L Jet Kit. The FAST manual would be easy to scan, but Carl's manual is spiral bound, big, and in color.
Let me see what I have a home as far as scanning gear. Anybody know if there a repository where these could be placed for historical/future use?
BTW I think I also have a FAST bracket and pulley and no longer expect to ever supercharge a 928. Probably.
Ill try to remember to look for the Intercooler.

LyndonJames

I’d definitely be interested in whatever you have! Even if I don’t supercharge right away. Maybe I could do it in a year or 2 🤓

PorKen

May not be there forever, but they are still on 928MS new website

https://928motorsports.com/installation-guides/

hacker-pschorr

Nope, it's all the same. There are so many crap intercoolers out there, and on top of that few folks seem to realize that if you don't make proper ducting, seals etc... the air will just go around the intercooler or heat exchanger.

Has a turbo LS swap in here recently, struggled to make 4psi in the manifold and intake air temps were off the charts. We dropped in a different intercooler of the exact same dimensions from a known good supplier. Boom, 10psi and respectable intake air temps.

If he only knew how to use the SharkTuner he wouldn't have to.....

For posterity sake, all that stuff should be hosted by the OC.