Carl Fausett

Wastegates designed for Turbos do not work well on superchargers. They must be modified, and even then they dont work too well.

We designed a BLV (Boost Limiter Valve) that will do the job.... it is here:
http://www.928m.com/parts/boostlimitervalve.php

If Tim does not want to use a larger pulley to slow down his output, this is the other option. He can leave his pulley as is, and the BLV will just bleed off the top end to limit max boost.

Rogue_Ant

There you go - Carl already has what you need
Would it make sense to re-route the "waste air" back to the supercharger?

Carl Fausett

No. This isn't like the BOV, where we want to route that back into the system because it has been measured by the MAF. This is installed close to the supercharger outlet and before the MAF, so you just dump to atmosphere.

Rogue_Ant

? It looks to me that the MAF is pre-supercharger - so any bypassed air would need to be re-routed back, not dumped to atmo...

Carl Fausett

I wasnt being application-specific.

You are right - on a draw-thru MAF install like Tims, once the air is metered, you cant dump it off.

I was talking about common push-thru MAF installs, where you just install the BOV and BLV anywhere between the supercharger and the MAF, and you can just dump what you dont want.

Sorry for the confusion. In Tims applications, he really would gain very little from a BLV. He cant dump it to atmosphere as it has already been metered, and he cant recirculate it because if he does the boost pressure will not change. He has to use the pulley method.

Lemming

It would be pretty simple to move the maf after the supercharger, would that then work with the BLV?

Rogue_Ant

I think that would work - but Carl is the expert here...

Carl Fausett

Yes, that would also work. We have experienced some issues with blow-thru MAF applications, however, where we can move more air through the MAF than it can measure. It will max out at 5 volts output and max flow - and we can move more air than that but the stock MAF cannot "see" it.

I think you would be fine Tim. The amount of air you are moving should be handilly beneath the max of your MAF.

However - if you know you are saving your pennies for the Electromotive kit then I'd just leave things as-is for now. You will be removing the MAF all-together when the MAP (Manifold Air Pressure) sensor is installed. That way you could just change your induction tubing once, not twice.

mikey_audiogeek

I know the Rotrex guys run an inlet restrictor. Sized correctly, it tends to flatten the boost pressure at the top end. Basic thermodynamics come into play here, but if you don't need to change your pulley and only want to trim 10% power at the top end, you should see no difference in belt life or inlet air temps. I can run some numbers easily if you like.

Carl has final say on the matter.

Lemming

I guess I have time to contemplate the next move, not going to race this car with NASA (GTS4) until next year. Most of the rest of this year will be getting the car dialed in at the track and running one PBOC race in November. I don't run enough with them to worry about points, so whatever class they put me is ok.

A standalone of some kind is what the car will deserve, just need for my lotto ticket to hit

I'll try to get some video this weekend at Barber.

edz968s

I`m lost on these Gen III injectors, the one`s I have fitted are from when the car was built, though they have been cleaned. So the stock ecu and standard injectors, with correct belt tension sorted, should see my power go up, but I`m running the stage 2 pulley with this configuration as I`ve never been able to get the supplied injectors to work, to rich, though I haven`t tried them with the FMU wound out. This weekends trial.

Lemming

Chris,

One thing to watch out for, if you decrease the FMU too much you may end up with an oscillation in the A/F. The only explanation we could come up with is that with very little tension on the diaphragm, it bounces????

If you cannot get the larger injectors to work, and are too lean with the ones you are running, try the Welbro 392 fuel pump with the lower flow injectors, cost was only $100.

Don't worry, the power is there, you just need to deal with the belt slip.

Carl Fausett

As to running a restrictor plate - no harm in trying it.

If installed after the SC it will make the supercharger work harder (higher parasitic drag and shorter belt life).

If installed between the air filter and the SC, it might be sweet in your application. It would leave the mid-range where it is now and only cap the top end.

Try it and see!

jm964cab

I saw some intercooler placement questions so maybe this will help some with placement ideas. The 951 intercooler can fit up front in the 968 without to much trouble. Get another stock hood latch, so two can be mounted on the sides getting rid of the one latch in the middle. Lower the radiator a little bit and it fits real nice. I can upload some detailed high res pictures if anyone is interested.


Tate

edz968s

Don`t think we could mount an i/c in the front, as the s/c head is central to that and has the piping and MAF in that area. I thought of mounting one in the front PU below the original intake, but cutting an inlet `mouth` where the license plate would sit, still a bit of a way to go. The a/c comp I recieved today was the wrong type, single belt rather than 6 groove.