My friend has an evo ( i know it doesn't apply to rx7s...just wait) and on the stock turbo pushes 22 psi. He said that getting a bigger turbo , but also running 22psi would result in more horsepower. Is this true? I'm still trying to decide on getting a bigger turbo, upgrading mine (154k on it ), or just buying an oem s5 replacement. I will be running about 8 psi daily driving and 12 psi on the track.
-My current stock turbo is going to get the wastegate ported soon because of massive boost creep.
-How do people build their daily driver engines to hold 15-18 psi? I know someone mentioned getting lower compression engines or something, but then another member started an arguement over that and left me in a confused state...so anyone?

 

Yes, in general a big turbo will make more power than a smaller turbo at the same boost level. The main reasons are that the compressor side of the big turbo heats the air less (= more efficient) than the smaller turbo, and it also generally proves to be less of a restriction on the exhaust side. The result is that the engine system flows more air and thus makes more power, even at the same boost level.

-Max

 

Yes, remember thats pounds per square inch, not how many CFM's its pushing. A bigger turbo at the same PSI as a smaller one will be pushing more more air period imo.

Using an electronic boost controller is the way that I see people using that kind of PSI as a daily driver. They never boost 18psi all the time, well if they're smart they wont. More air means more fuel, and that means shittier gas milage, so running at say 8psi is fine for the street. But if she or he wants to kick it up a notch, a touch of a button can set it so that its running 18psi again. simple as that really. Of course, you need more than just the boost controller to do this properly..

 

a big laggy turbo wont spool in lower Rpm's anyway

if u hit full boost at 3,500 RPM u can leave it at 22psi

just shift at 2,800-3,200 etc...

 

Cool so anyone know how I can build my engine to safely hold 15 psi? I have ran it at 15 at the track before, but turned it down beacuse people said I would break something. Oh yeah my turbo was a nice amber color ....fmic costs too much

 

please tell us that was the turbine and not compressor

 

A stock block can handle 15psi no problem. I've been running 15-17 daily for 3 years. You don't need to build anything fancy engine wise.

But you certainly do need support mods to run 15 psi...

 

Oh it was just the hot side that was amber :P That's the only part of the turbo I can see until I replace the crappy stock intake piping. I have most of the support mods needed:
upgraded fuel pump, f-con, fuel cutoff, boost controller....some other crap I don't remeber..soon the msd ignition and 720cc secondarys are going to be ordered I haven't had that ignition problem that would require for an upgraded ignition, but I'd rather be safe...same with the secondarys.

 

^bump

 

bump again...what type of turbo would be good if I don't want to spend more than 1.5k fir turbo and all the **** needed to install?

 

try a t66 might be costly but worth it

 

Here is a vid of a cusomters car running a TO4S @ 22psi (every day !) Has been going for a long time and it gets used like this so often its a joke !

http://ausrotary.dntinternet.com/for...ic.php?t=63839

Engine is a 2buk ******* with no race mods or preperation... nothing !!!

Makes 430rwhp on our Australian dyno's (around 530~550fwhp)

There is NO NEED FOR A BIGGER TURBO THAN THIS FOR A STREET CAR.

 

nice video rice!