turbo question...which to go with? single?
 

FD rex, im going to want to put down 400+ RWHP. heres my crux tho'...i hate turbo lag. the car will see lots of back roads and track time so im going to need a turbo set up that will spool very rapidly. what would be the ideal set up for high ho pow low lag? ceramic ball bearing single turbo of some size? a better twin kit?
new to the rx-7 world and need some help! thanks! https://www.rx7club.com/ubb/smile.gif

At least one person here approaches 400 rwhp with the stock twins.

Mike

does having 25psi on your boost guage by 4200rpm sound appealing?

hell yeah it does. im thinking about a set of upgraded factory twins, what are you running.

also i heard that the RX7 is not smooth at all...like, the first turbo spools and there is a drop off and then the second hits. is this true?

Mike (red-rx7) has a T04 with 1.15A/R divided housing in his ported FD, he is able to pull 26psi by 4200rpm (thats when his wastegate wasn't working due to incorrect plumbing hahaha) he is getting boost at 2800rpm with a non divided manifold, with a divided manifold that could drop possibly 500rpm or a tad more so positive pressure at around 2300rpm, hows that sound?

Thats not funny! Besides worring about popping the motor with this indefinate amount of boost (definate by my foot I guess), I had to worry about the oncomming traffic since the car went instantly sideways.

Mike

EXACLTY what i want. so hes running a single TO4? what trim wheel? 26lbbs of boost at 2.8/2.3 k rpms is REAL nice. whats that equate to in terms of RWHP?

I was thinking about a T04S turbo with divided exh. port from www.xs-engineering.com and score a divided manifold somewhere with a FMIC. Prob. spool really quick. I'm gonna do more auto-x than drag.
-Pete

------------------
'93 Montego Blue
Pettit Intake
PFS Midpipe
PFS Cat-back
PFS boost guage
Pettit Pulleys
RP Aluminum Radiator
Knightsport bumper
Turbo Inside sticker (worth 10 hp!)
Bonez clutch and lightweight flywheel

Coming Soon: GReddy 2-row FMIC, APEXi AVC-R Boost controller, APEXi Power FC

AOL IM: SpeedRacerGTP

I like T04E's personally but you won't get much more out of it than 400 rwhp. And that's pushing it. A T-78 will make 400 though, no sweat. If done properly, they usually get full boost by around 3500-4000 RPM which isn't too bad for such a big turbo. The Apex IHI kit supposedley spools quickly but once again, it's tough to hit that 400 mark. They're more in the 360-380 range.

I wouldn't recommend upgrading the twins for two reasons. With the differently sized turbine wheels, the turbo becomes unbalanced and the connecting shaft isn't up to the stress. Second, if you're running a lot of boost, you're probably going to blow off a vacuum line sooner or later even if they're tie wrapped. Since you'll be spending the money, just go single.

TO4 E,B,R,X have no problem producing 490rwbhp on dynojet "American dyno's" Infact when upgraded to "R" spec they are good for 650+bhp or 550+rwbhp.

Get the facts from the experts such as XS Engineering on TO4'S or many Australian tuners, they are cheap, make heaps of power and are big enough for everything but Peripheral port 13B's....

I would go with a TO4 based turbo if it is available for the above reasons (and many more), however if another suitable turbo such as a Greddy T78/88 or equiv was the same price then this would be a good choice too.

RICE https://www.rx7club.com/ubb/smile.gif

thanks for the input guys!

Don't forget about running your stock turbos in paralle. I've heard you can run low 11's with that setup!!

Rice Racing, you're absolutely correct about T04's being capable of big hp #'s. It sounded though like he just wanted a "kit" that spools quickly and makes decent power without 20 psi. Unfortunately, a T04 wouldn't cut it then though XS does offer some bigger T04's. I didn't feel like getting into a discussion about engine management, boost, fuel (lines, injectors, pumps, etc.), and all the other stuff involved since he is "new" to the rotary world. *sigh* I hate questions like this. Though it beats that one post from before the last hack, "How do I get 600 hp?" People got all pissy because I told the guy to buy a Henessey Viper.

I've dynoed 417 RWHP corrected and 443 uncorrected with an apexi turbo 15 psi and a ported engine.

To everyone who has posted their HP numbers: Would you mind posting at what rpm that is at? Just a little side thing I am interested in lately.

Impressive. Very impressive (my Darth Vader imitation). What octane gas were you runnning? I'm sure the port job helped a lot. There was a subject thread a while back about the APEX kit here in America only making 360-380 rwhp at around 15psi on several cars.

The 417 corrected RWHP run was made on Research 94 octane and 104+ octane boost... my guess is around 90 R+M/2 octane. This was at 15 psi on a low compression ported motor.

Sorry the run was made with a bad rpm pick up... so no torque numbers or rpm readings but my guess is max power around 7000 rpms. The hp curve was relatively flat from 6000-redline... the power never dropped off.

Last week I made 334rwhp on 12psi and 98octane pump fuel. Peak was made at a tad over 7000rpm. And that was on a dyno dynamics chassis dyno too.

[This message has been edited by AJC13B (edited May 17, 2001).]