I have a stock s4 turbo and anyone who has a TII and has increased the boost knows that the turbo has an asthma attack anywhere above 6k. 12 psi is plenty of power for me right now so I'm not looking to get a bigger turbo I just want to find a way to modify it (hybrid maybe?) so that the car doesn't feel like its falling on its face on the top end, cuz we all know that rotaries are known for their pull all the way to redline.

I've heard of clipping the hotside? Anyone else heard that?
Also hybrid combinations... any suggestions with these?

I have all the accomodating mods to support such an upgrade besides a front mount, just wondering what other options are out there before I go tearing the turbo off..


Thanks for the help fellas...


~Ant

 

BNR hybrids.

 

I looked at their website and they want $625 for a stage 1. Is this reasonable?

 

well, they are rebuilding your turbo and porting the wastegate. You are paying for the parts, the time involved, and the expertise of a specialty shop.

 

IMO the only unreasonable thing is you're not going for the stage 3+ :P If you're gonna go, go big!

Seriously though, you should talk to the BNR guy about sizing. Depending on your goals for the car he'll help you pick the right thing.

 

a little off topic, but Gene I'm actually about to head to NYC for the weekend, just took a look at your location real quick, lol


anyway, I think I would get myself in way too much trouble in NC with a stage 3.... I'm pushin it already

 

I'm gettin the st.3. You know what's gonna happen, you're gonna get the stage 1 and be happy for a month then your gonna want more. Get the 3 and be done with it. For now.

 

Cool, hope you have a good time. The weather is gonna be iffy.

What part of NC? If you live near VIR you can wind that turbo out there no problem

 

Had a great time in NY man, the woman are pretty bad too

Anyway, so I'm sold on the stage 3 BNR turbo, just looking at the price difference it worth saving up just a few 100 dollars more for such a significant gain in power. Has anybody who has run that turbo had problems maxing out 720cc injectors with that turbo?


cough cough...anybody selling theirs??

 

Fuel calc:
http://rx7.com/cgi-local/2ndgencalc.cgi

How much tuning ability does the rtek have?

Also how much track time do you have? No point in having too much power at first. Hell I've been going for several years, but my meager 213RWHP can be a handful at times.

 

if you got the money, ditch the t2 flange that the hybrid turbos offer and let it all hang loose.. get a 60-1,60-2, or maybe even a t04r. the bnr 4 is a bit laggy for my liking but as of right now my wallet isn't letting me get anything bigger..

 

will a bnr turbo hold boost better than the stock s4 turbo? What I mean is I have my boost controller set at roughly 12 psi, and somedays the turbo will hit it no problem, but I drove it today and it wanted to sit at 5 and taking forever to spool? what's up with that?

 

You don't want to try running a stage 3, 60-1 turbo on an Rtek 1.7. First, running only 2 720cc secondaries, you'll run out of fuel before you come close to maxing the turbo out. Second, your timing will be all wrong & the stock fuel table will make you run lean under boost. You need an Rtek stage 2, or a standalone to do it right. You could get by with an SAFC, but it's still sketchy.

 

Thanks for the info. I was thinking about upgrading to a 2.1 for some tunability as well. So I should probably through in some 1000cc secondary injectors too?

 

Four 720s may be able to handle the 300-350 whp potential of that turbo. If in doubt, 720/850, 720/1000 or something similar would work well. You'd need to do a lot of fuel tuning in the upper RPM range to get it right, but that's better than maxing out the injectors.

 

AITS have a lot to do with this. The hotter the air the slower the turbo will spool and the less boost the turbo will make. You need a better intercooler, especially if you plan on any sort of upgrade..

 

like whats said above, temperature also plays a big part on how fast the turbo spools

 

Good point, but I'm trying to find a way to run these kind of boost levels with the stock top mount, I don't like the idea of air having to go through 10 feet of plumbing. I'll be getting a water injection kit to see how that affects the AITS.

More on that subject, I've heard of several people saying that they're boost would start to fade at redline or a little past running the bnr turbos with a fmic, and the ones who still had their tmic did not. So if there's a way to lower AITS w/o running the fmic I think that would make the best combination.

 

Truthfully if you run a stage 3 bnr or equivilant with say a greddy style front mount like mine it shouldnt have a problem filling that piping and intercooler quickly. I was getting more info on my turbonetics hybrid turbo and its a stage 3 something like a 60-1 from the info I got. I run about 15-16psi and achieves full boost around 3-4k and keeps a constant pressure in the fmic system. that and AITs are much cooler than ever had with the heat soaking tmic. And also the stock tmic pretty much becomes ineffecient after 8-10psi cause it cant effectively cool the air passing through it expecially at higher road speeds cause of the design of the hood scoop and aerodynamics of the car itself. The stock turbos effeciency is about 12psi too, before it pretty much becomes a really hot compressed air mover. So i guess give that some thought and make your decision on keeping your tmic and addin water/meth injection.