Iwanna928

I have been looking at ways to improve the setup on my car.

The issue is the setup has two TB's and one Maf so I do not see how that will ever be a optimal setup. I do not want to tear into it and make a cutom single inlet with one TB and MAF.

I have been looking at a F.A.S.T. 2.0 EFI system. It is speed density so I could ditch the MAF but keep the original setup.

Any thoughts or knowledge on this setup or product. It cost around 2200 bucks.

I am not interested in using the computer in the car as tuning for boost is a little out dated. I am looking for a affordable product that will take care of business.

Fabio421

Seriously!?!?!? You wan't to f@*k with it already?

The stock LH computer will be able to be upgraded to a MAP sensor very soon. John Speak is working on this now. You will be better off going this route and then having it Sharktuned.

blown 87

Honestly Stephen you have bigger fish to fry with that car.

Lizard928

Fabio,
I am not sure if the MAP based system will be offered to LH2.2 people or not, John will need to confirm on that.

Look at VEMS, it will be cheaper than the fast system with more features.
If you go this route, ditch the distributors and do distributorless ignition with dual knock control.

Jon B.

What about BS3(Big Stuff 3)?

Iwanna928

Greg You are probably taking about that leaky oil seperation system. It will be ripped out soon and replaced with non plastic leaky parts.

The whole thing will be gone through.

Will do Colin. Thanks.

blown 87

Yes, that and a few other things.

Lizard928

nut behind the wheel?

Iwanna928

Guilty as charged!

Honestly I have driven a fair share of cars with positive displacment blowers. This car is awesome do not get me wrong but with one Maf reading flow from one TB and trying to figure out what is going on on the other side causes driveabilty problems. Problems like stalling at lights after it is warmed up, hesitations and bucking before boost. At WOT she runs like a dream but around town she can definetly improve. I know she can run much smoother with a better system for her. One that has more tunability. This is not about HP gains, it is about proper tuning.

That said I feel there is power to be gained but only so much. She is fast enough already. I just have an idea of how she should be and I will acheive that goal!

Colin that system looks cool! Thanks again!

Fabio421

I doubt that these problems are caused by the car only having one MAF. Lots of boosted cars use this method. As long as both intake tracts to the MAF and dummy MAF are similar and one isn't obstructed, you can safely assume that the air flow seen by the MAF is 1/2 of the total. Do you know if this car has been sharktuned or if it is using a RRFPR for fueling? When it stalls, is it stalling when you come off the throttle or is it stalling after its sitting there idling for a moment? The bucking could be a lean condition. Part throttle tuning is tough to get right if you're using a RRFPR but shouldn't be that bad if it's been Sharktuned correctly. I'm having trouble remembering when D.R. sold this car to Dr. M. It could have been back before he had a sharktuner for that version of the LH. Dave Roberts has also started using a pressure operated micro-switch to fool the computer into ignoring the O2 sensor as soon as it registers any boost pressure at all. That way you aren't fighting the o2 sensor at part throttle. Talk to Andrew O. about it. I know he was one of the early adopters of this method. He can fill you in on his experience with it.

These threads might help you.

https://rennlist.com/forums/928-foru...w-thread.html?

https://rennlist.com/forums/928-foru...r-thread.html?

928er

I think the best advice would be to get everything working as the factory intended. then work on improving performance. I'm guessing this advice will be ignored as the rest of the advice has been.

Iwanna928

Fabio Thanks for the info. Yes the car has been sharktuned. Has two different chips that came with the car. If memory serves correct DR helped Ed tune it. The car does have a adjustable fuel pressure setup. Ed turns it up for the 8lbs pulley but I have only driven the 5.

The car stalls when you are coming to a stop on the brake. It doesnt happen all the time, here and there. It seems to happen out of nowhere. When it does sometimes you have to turn her over a few times to get her back on track. It could be dangerous making a left hand turn wirh on coming traffic and she decides to stall.

I understand in regards to the MAF but I feel and so do the guy's I know from my Supercoupe days that it isn't really the way to go. They live and breath positive displacement blowers.

I will read up those threads that you posted. Thanks!

Aren't there some FLA guys working on a Mega Squirt system for boosted 928's. There must be a reason.

Lizard928

I'm not a fan of MS for boost due to the lack of knock sensor input out of the box.

928mac

Dose it buck when you are stepping on the brake, just before it stops?

John Speake

At present the ST-MAP system is being developed for the 87> cars.

The configuration that DR used for the intake was somewhat of a compromise, I would favour a MAF in each leg with a combining box.

But don't discount a single intake/MAF, Dan Prantl is using that on his twinscrewed car with success.

However the low speed, light load issues you mention are more likely to be caused by the remapping not being optimum. Since that car was tuned we have the excellent SharkPlotter program from Jim Corenman. This means you can drive the car and datalog for up to an hour, load those datalogs into the SP program when you get home, and it will produce a much smoother optimised map for you.

Much better than by just using Autotune.

But you DO need a knock detect system.... !