SC14 GZE plenum design

[soopachargen]

I've put an SC14 onto my GZE in my rolla. I have a few minor electrical problems but all is well.
At the moment the GZE still has a larger crank pulley on it so i'm looking at sticking a smaller one on it to lower the boost so that the injectors/computer can handle it.
Question 1 Can i use a redtop crank pulley? Is this identical?

Also due to reasons that arent up for discussion, mainly the front mount and the two metres plus of intake plumming, i'm going to change the charger setup to a blow through throttle body setup. To achieve this i'm looking at a custom intake plenum similar to the one off the TINYZ ae86. I'll be using a r32 skyline BOV to vent back into the intake when i come off the throttle.

Question 2 Where do i want my blowoff valve to recirculate to? Obviously after the AFM, but do i want it going in before or after the charger?

Question 3 Being forced induction how important is plenum design? Can i get away with just a "log type" plenum and or would i be better off with something a bit more specific and if so what sort of design am i looking at? What size? What length runners?

I think that covers most of what i want to know.

[Ako]

I can answer number 2 at least...

BEFORE the charger - otherwise it'll just be venting back to air which is pressurised as well.

[Mr Revhead]

no1 no, the s/c has a very different pulley

[soopachargen]

Ako: that was the logic i was working with... thank you!
Revhead: bummer

any one got a standard gze crank pulley??

[Stu-]

Use the larger crank pulley you have and stick with the AFM and stock ecu. People have been using AFM setups with turbos without any problems. Might have to knock the timing back a bit thats all...

[soopachargen]

is the stock ecu gonna supply it with enough fuel? I've heard stories of 20psi...

[slighty_sykotic]

I might be able to offer you my pully from my gze if you want, ill have to have your bigger one though. But im not using the supercharger anymore so it doesnt matter to me...and i doubt the extra revs is going to hurt the alternator or the water pump/power steering.

If you get stuck, get back to me and see if we can sort out a swap.

--Sykotic

[soopachargen]

nah dude the swap to the smaller pulley is only untill i sort out what ecu im going to use.

[soopachargen]

What do i need to tap into the plenum vacuum wise??? anything else that the plenum needs??

[KinLoud]

Plenum design does matter!
Some people say "because it has boost the air just gets forced it no matter what" CRAP!
Some considerations will change a bit due to changes in air density and therefore resonance of the air in the intake and into the cylinders,
Bigport head- use bigport NA intake if you can
Smallport head - use smallport NA intake if you can
Both of these will be better than the 4agze standard intake manifold with short uneven runners and 90 degrees turns.
If you are making a new intake manifold/plenum use the lengths and daimeter of the smallport runners as a good guide. Don't go bigger on the diameter of the runners because you will lose air velocity which is the key to filling the cylinder with lovely pressurised air. Shorter length will raise the rpm at which you will make peak torque - you probably don't want higher rpm for peak torque!

Ken
Ham
021 408 863

Ken
Ham
021 408 863

[soopachargen]

awesome ken... good to see there are still people with knowledge here...
I guess i want nice long runners to keep my torque nice and low... how long is too long? The N/a plenum wont fit without mounting the supercharger lower and putting it very close to the steering rack and other things. Would it be alright to just copy the N/a manifold but make it to clear the charger??

[KinLoud]

Copy n/a manifold runner length and diameter... it will be a pretty good guide. You might want to make the plenum a bit bigger - do some homework on this.... bigger plenum (within limilts) could give slightly more power but could give you poorer throttle response can't remeber all the ins and out of this.

Dumb question - what would be easier...
1 - s/c on the front of the motor maybe mounted where the aircon pump goes and use factory n/a intake manifold (might need custom exhaust). This would give a shorter intake/intercooler/head distance and less volume = less lag
OR
2 - custom intake manifold with factory s/c location.

Just do a bit of homework...

Ken
Ham
021 408 863

[soopachargen]

personally for me its easier to get a plenum made up than get all the intercooler piping remade and a bracket and tensioner made up for the charger... any ideas would be great tho

[Bazda]

An easy way for the plenum it to make it a log type but have a tapering tube so the air gets spreads more evenly along the cylinders.
The get some runners made from tube that flare out to an oval for mounting it to the head and welded to the tapered plenum.

Oh so its now boosting ok?? you fixed the 8psi prob?

[soopachargen]

jesus barry... get back on msn if u want updates...!!!