hacker-pschorr

We ran into the same issue with the green Bosch 42's. We just cut the grooves in ourselves.

Michael Benno

Same here; if you order your injectors from https://www.fiveomotorsport.com/fuel-injectors/ they will make sure the groove is cut in the correct location and the correct size O-rings the @Mrmerlin mentions above. Plus, they will ensure a matched/balanced set and they will provide you with the latency tables required for tuning. I have used them a couple of times and they are excellent.

Crumpler

Wow. I bought my 42 pound green from them and slapped them on without thinking about compatibility issues. They must have done it for me. It is a quality group.

Rasant Products

Okay folks - lots to update you guys on, but we're suddenly having a problem... Hope that somebody can point us in the right direction please.

We were tuning away here - without any issues - the car started right up yesterday for the first time with the new SharkTuner PEMS installed. We had already changed the injector sizing and all of that was fine. Today it started right up again, we pulled it out of the shop and we proceeded with tuning through the SharkTuner. The car was running for a solid 30+ minutes, but then suddenly we lost the MAF signal while at idle in the parking lot (the value just doesn't respond in the SharkTuner software at all - it shows zero!)

We tried plugging in another known-good MAF that I have here, but had the same result! We have 12-volts to the MAF (at the MAF plug with it unplugged), as well as continuity back to chassis ground from the MAF plug. We confirmed that there is a signal coming out of the MAF that makes it back to the LH box (2 volt - pin-7.)

Still, the MAF value in the SharkTuner shows zero while the car is running. The car does run, but the mixtures suddenly went seemingly rich (what has been described online as 928 limp-home...)

What's going on - any thoughts?

Michael Benno

Sounds like a connectivity issue in the harness. you can validate this by unplugging the MAF while running and see if there is a noticable difference.
I'd recommend you follow the test proceedure in the WSM for the MAF and connectivity to the LH.

See WSM manual 1A page, Section D25-15 (page 277). Test Point 5 goes through a through test process of the system and provides the necessary pin numbers and voltages

Rasant Products

Thanks Michael. Yeah, that was the first place that we looked! We followed those exact checks and steps. Suddenly it all started working again when we swapped MAFs (but then it also worked on the other MAF again.) Inconclusive. Weird - looks like we're chasing a bit of a ghost in the machine. This is partly why I'm advocating within the team that we only sell the kits with a known-good, rebuilt MAF (at a minimum.)

In this case though, it could be in the connector. Taking a break from it for a couple of days to take care of other regular business. Back to it again on Monday.

Crumpler

I know Blippo about the Sharktuner process but if this was happening on my S3 I would be worried that my LH was dying.
Is it a know good computer?
This is where things get maddening.

nine-28

Excellent news!!!
I have acquired my C38-81 some 10 years ago, but as I would have needed to fabricate (and hide the supercharger from the inspector) all brackets etc the project faded. I rebuilt an S4 block with GT cams and machined pistons added with 2mm Cometic head gaskets to get the comp ratio to 8,8:1. I still have that engine, drove it for 28tmls as a N/A. Tried also to get parts from Edgar but without results. Could you present some prices/pricelist for a kit without the supercharger and its lubrication system?

nine-28

Any updates available?

Rasant Products

Turned out to be a MAF issue. We installed another stock, rebuilt unit and everything worked again. Anyway, it's been a while since I have updated this thread, so it's high time I guess! Here goes -

We fired up the car after the Rotrex installation and have been working on sorting various aspects of the kit (where to mount the Rotrex oil cooler, where to mount the intercooler's heat-exchanger - when the time comes to add one, a rework of the injection-molded intake snouts (the original design interfered with the hood a bit), fuel line routing and things like that.

We're fighting a few problems related to the base design of the 928 - the primary issue being oil drain-back and crankcase ventilation. The question becomes whether to "P" or not to "P" in the PCV. We've been fighting some sorting issues (including the dreaded challenge keeping the engine oil in the sump.)

Anyway, we went back to the dyno yesterday with a temporary catch-can solution and got the mapping 90% there before we ran out of appointment time.
This iteration does not yet have an intercooler / heat-exchanger installed in the system.
We are only running 5 psi maximum boost on an 85mm Rotrex pulley.
We have kept the fueling pretty fat to stay safe.
We have not yet done any ignition timing tuning (other than to check for knock), but ignition is also kept really safe for now.

So, there it is - 385 RWHP and 346 pounds of torque (up from 270 RWHP and 260 ft-lbs torque...)

Next step is to continue refining this version of the kit, do some more road-tuning to clean up transitions in the maps and then get read to start making it available to others.

After that, we'll move on to installing the intercooler and heat-exchanger, a smaller supercharger pulley on the Rotrex and then start mapping for that setup with something more in the 10-11-12 psi+ range.

Rasant Products

Hi There! Replied to your emailed inquiry privately, from the Rasant email as well...