Sprintex 335 Testing & Progress

[ATL BRZ]

Originally Posted by moto-mike

A bigger problem that we've found is fuel starvation under load in left turns. We've had some problems with it before at 1/4 tank or less, but we were fuel starved as high as nearly 3/4 at the event this weekend. We had two long left hand 3rd gear sweepers and on both we lost all power. Unsettling feeling when at full tilt. The issue is that at high boost running e85 you suck the fuel pump bucket dry in seconds. And the crossover tube is drawn by a venturi, which falls apart under high stress like this. We're looking at cost effective ways to battle this. Yes, we could keep the fuel tank at full, but at 19 psi on e85 we won't make it more than 10 minutes on track before having the same issue.

This is not a kit issue really--just a high power track car issue. No doubt just the first of many as we keep pushing this platform.

I have the same exact problem at the same fuel levels with my 205whp NA car running E85.

In for a solution!!

[King Tut]

Originally Posted by ATL BRZ

I have the same exact problem at the same fuel levels with my 205whp NA car running E85.

In for a solution!!

You know the solution. Surge tank.

[Xero-Limit]

Originally Posted by King Tut

You know the solution. Surge tank.

Yup...we'll figure it out. We have something like 8 track days scheduled in the next two months and no way the miata will make them all (300whp SC...)

BRZ will get some love as time allows and we'll flog it at NJMP or Lime Rock. Just no way I'm putting it on there with stock brakes and no oil cooler. Custom bracket will be no problem as we did with the Greddy install two years back.

[dstrout]

So I have just read this whole thread. Assume my parameters are a stock motor and exhaust, always good 93 oct with occasional tanks of E85 when handy, 6-8 track days a year, and I'm mostly looking for silly-strong roll-ons from 2500 - 4K rpms on a daily basis. I'd also like to hit an honest 300 hp just for the ****-wagging rights of 9 lbs / hp.

Do I understand correctly that my best plan is a 335 with a small-ish pulley, a BOV to limit boost on the high end, and possibly a lowered rev limiter? Or could I do what I'm asking with a 210, given that I'll never build up a motor for this car, so don't need the headroom of the 335.

[s2d4]

No

[dstrout]

Originally Posted by s2d4

No

I'm listening...

[350matt]

Originally Posted by dstrout

So I have just read this whole thread. Assume my parameters are a stock motor and exhaust, always good 93 oct with occasional tanks of E85 when handy, 6-8 track days a year, and I'm mostly looking for silly-strong roll-ons from 2500 - 4K rpms on a daily basis. I'd also like to hit an honest 300 hp just for the ****-wagging rights of 9 lbs / hp.

Do I understand correctly that my best plan is a 335 with a small-ish pulley, a BOV to limit boost on the high end, and possibly a lowered rev limiter? Or could I do what I'm asking with a 210, given that I'll never build up a motor for this car, so don't need the headroom of the 335.

you can limit the boost in the map by getting the throttle to close down so there should be no need to fit a BOV
if you want 300Bhp crank then you can get this without the 335, if you want 300 Whp then thats a different matter

from waht I've seen so far though you need a very savvy tuner to avoid blowing the engine with this big blower and a stock block

[s2d4]

Let me know how and where you are going to install that BOV?

[Chad86]

Originally Posted by 350matt

you can limit the boost in the map by getting the throttle to close down so there should be no need to fit a BOV
if you want 300Bhp crank then you can get this without the 335, if you want 300 Whp then thats a different matter

from waht I've seen so far though you need a very savvy tuner to avoid blowing the engine with this big blower and a stock block

This is where @moto-mike's expertise comes into play. My 335 will hopefully be getting installed in July and I will be getting Mike to perform my tune.

[SprintexUSA]

Do

not

EVER

put

a

blow

off

valve

on

this

system.


Thank you.

/PSA

[dstrout]

So if I follow, a blow off valve is not a good idea?

My original post was actually meant as a serious question, I was not trying to troll. It didn't occur to me you could manage the risk of overboost through tuning. I think its going to take a while for me to get my head around the intersection of software and metal.

Thanks, and carry on!

[Dream20b]

there is no potential for overboost on an SC due to being belt driven.

[Ultramaroon]

Originally Posted by SprintexUSA

Do

not

EVER

put

a

blow

off

valve

on

this

system.


Thank you.

/PSA

bee

cuz

it

already

has

something

to

do

that

job

[SprintexUSA]

Correct. A recirculation valve is the opposite of a BOV. Ours is open under vacuum and closes under boost. It does not vent "excess boost" because there isn't any excess boost. The only time you might get overboost is if you downshift into the wrong gear and hit 10k rpm. By then, excess boost is the least of your worries.