Page 1 of 4

Suction type or blow through maf?

Posted: Mon Dec 08, 2008 8:36 pm
by bradystrib
Okay, so if you didnt know yet, I have a 240. I plan on building a KA-T. Already have some 550cc injectors, z32 maf, gt2871r (or stock sr t25),safc,blitz dd bov, some more stuffs......uhm so anyways yeah, I have heard different things as far which is better. I have heard about stalling issues and idle issues with a suction style. I also hear about exploding MAF's with the blow through. I don't plan on running more than 15-17 lbs with the 2871 on high boost and maybe 8-11 on low boost. Any thoughts???

Posted: Mon Dec 08, 2008 8:54 pm
by JJ Alfano
stock ecu or stand alone? if its stock with safc, i would just run suction since its easier

the bogging is from the a/f ratio going rich when the blow off valve releases

Posted: Mon Dec 08, 2008 9:05 pm
by P.Haire
blow through is real deal race car stuff.

Posted: Mon Dec 08, 2008 9:07 pm
by foilman
Well, I've got a lot of experience there.
DO NOT RUN A STOCK SR TURBO ON YOUR KA. It's not even big enough for the SR it comes on and it will probably be worn out and tired when you get it anyway... but even if it's brand spankin' new, seriously, don't do it.

My FOERST turbo setup back in '02 was blow through and so were the 2 after that. I even tried the 3rd setup both ways at JWT's behest since they supplied the ECU, but after a few days was like, "no, fuck this, it works tons better my way". I never had a problem exploding the MAF, s14 or Z32. The response, stumbling, mileage, all better blow through. I have seen 1 MAF popped by boost, but he was running a lot. I was usually running 9-15 psi, 18 for a little.

Posted: Mon Dec 08, 2008 9:18 pm
by bradystrib
foilman wrote:Well, I've got a lot of experience there.
DO NOT RUN A STOCK SR TURBO ON YOUR KA. It's not even big enough for the SR it comes on and it will probably be worn out and tired when you get it anyway... but even if it's brand spankin' new, seriously, don't do it.

My FOERST turbo setup back in '02 was blow through and so were the 2 after that. I even tried the 3rd setup both ways at JWT's behest since they supplied the ECU, but after a few days was like, "no, fuck this, it works tons better my way". I never had a problem exploding the MAF, s14 or Z32. The response, stumbling, mileage, all better blow through. I have seen 1 MAF popped by boost, but he was running a lot. I was usually running 9-15 psi, 18 for a little.
well, good deal then. The 2871r it is. And i think i am leaning more towards the blow through set up. Thanks a ton for the info mr. shorts.

Posted: Mon Dec 08, 2008 10:56 pm
by P.Haire
go bigger.
t3/t4!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Posted: Tue Dec 09, 2008 8:48 am
by bradystrib
P.Haire wrote:go bigger.
t3/t4!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I've thought about it....arg. I dunno, i like the simplicity of bottom mount stuff....but top mount is ballin...

Posted: Tue Dec 09, 2008 9:46 am
by ChadMK4
Then whats the safe psi range for blow through? I've been thinking of this too but I was told that the chance of popping to MAF is to great. I'm gonna be running the 20g. I don't know what amount of boost yet. I would assume 14+. But I know that the bigger the turbo the less boost needed to make more power. I"m assuming because of the volume of air being forced is greater with a bigger turbo.
But that has always confused me too. Because in the end, when it reaches the plenum it's still 14 lbs...? 14 lbs is still 14 lbs right? Anyone got a conclusion to my confusion?

Posted: Tue Dec 09, 2008 9:53 am
by POOPscandal
its cause pressure =/= volume or something to that effect.

Posted: Tue Dec 09, 2008 9:56 am
by ChadMK4
Uum............. What?

I'm not an equation kinda guy. :-*

Posted: Tue Dec 09, 2008 11:41 am
by andysapp
That's right. He's a happy meal and a Blockbuster kind of guy.
Cheap date = FUN date.

Posted: Tue Dec 09, 2008 12:18 pm
by kOOpA
ChadMK4 wrote:What?
the amount of pressure the air is under is not equal to the volume of air going into the motor. saying you're running 20lbs of boost is not saying how much air is entering the motor, it's just saying how dense the air particles will be.

air particles entering the motor = air particle density * air volume

Posted: Tue Dec 09, 2008 4:16 pm
by ChadMK4
So it's not based on pressure?

Posted: Tue Dec 09, 2008 4:22 pm
by andysapp
Image

Posted: Tue Dec 09, 2008 4:58 pm
by ChadMK4
andysapp wrote:Image
ok its settled.. ^^next years Halloween costume!!