Turbos - stock vs 99 spec
 

I have gotten a LOT of conflicting information regarding turbos, so I pose this question to people who have actually switched from stock to 99 spec....Did you notice a difference? If any other mods were done at the same time please include that info as well.

nope. Didn't notice much of a difference. I did have the car ported and increased the boost. I expected to be totally blown away. Instead if feels about the same.

I road in a totally stock working car and it seems to boost quicker. I do have a boost issue where I am not hitting 4psi with no load, which maybe part of the problem. However, I am hitting targeted 10-9-10 13-11-13 with my lo/hi boost settings.

If I where to do it again and stay with twins, I would probably go the BNR route. FWIW

If i didn't get these 99specs for a good deal, i would've gone with BNRs.

might be because my old twins were a bit worn, but my 99spec pulls noticeably harder and hit the 2nd turbo switchover a lot quicker at same boost level compare to my OEM twins.

Being that the 99s will be brand new and you'll be ditching old tired turbos, you'll probably see a bit of a difference.

I just recently gave my dad's motor a mild port and build, and he bought brand new oem (usdm) turbos. Car is much faster than it was before at the same boost level.

the turbos of the 99 spec spool faster.
I think they are also more reliable at higher boost levels

Running stock port with ~12k on the engine and turbos. I'm getting set for these upgrades with all parts in hand...Greddy FMIC and downpipe, Apexi intake and N1 catback, Power FC, Bonez hi-flow cat. I have a set of 99 spec turbos with ~15k on them. Should I put on the 99 spec turbos or sell them and hold out for the BNR's?

Previously I was told, with the other mods I have in mind, I would also need an upgraded fuel system and ignition to run the BNR's. The total cost was approaching $4500 and I didn't want to drop that much all at once so I picked up the 99 specs instead. Based on what I'm now hearing I might as well stay with the stock turbos.

Negative, they are LESS reliable at higher boost levels.

I think we need a sticky thread at the top of this section on this subject :)

how do you change the boost level on stock turbos?

^^ gotta hook up a boost controller

manual or electronic.. both work


+1, yes. OEM vs 99spec turbos and difference between Efini vs 99spec :P

You have a lot of reading to do ;)

Spend some time in the archives and you'll be up to speed.

If you are going to upgrade the turbos, and rip everything out, you might as well go single turbo in my opinion (once again just my opinion).

I have stock U.S. spec turbos that were on my 94 rx7 and made 301 whp at 15psi with the Power FC (which can cantrol boost levels on stock turbo's using stock boost solenoids), 3inch TB, other bolt ons after Dee Karagiannis tuned it. He told me that with stock twins with No porting you will max out at 320whp!!

So if you want more than 320whp go Single Turbo not 99 spec turbo's.

Here is a link to what a Well Tuned rx7 can do with stock Apex seals and a single turbo:) ENJOY!!

http://videos.streetfire.net/video/1...2c00e8acb1.htm

Not interested in going single, but I'd like to know more about your setup.

And, no offense Goodfellas, but from my experience the search engine on this site is marginal at best. I did a search for threads on increased boost from stock turbos and got some threads on seats, wheels and even a cup-holder (?). I did get some on the turbos too though, so I'll do more research. It's just hard to find time to read a bunch of superficial garbage to get 1 or 2 tid bits of info, especially when you work as many hours as I do.

The problem is you didn't bother looking in the 3rd Gen FAQ's. If you look there I am sure you will find all you need. Or else go back to the old Big List saved emails on www.fd3s.net, it is older but TONS of good information as well.

I beg to differ that you'll "max out" stock turbos at 320RWHP. I know this because my previous FD made more than that on stock motor/turbos as well as a few other people on this forum.

Everyone always says go single but everyone forgets that you are far from street legal when going this route and some people don't wanna deal with the ways around that. I'm planning on going BNR's in May so I'm curious as to what differences there are at equal boost levels compared to the stockers.

even though ur changing turbos the 13btt is completely different to the 13brew motor

if you want more HP output, there's a lot of other things that can help you to have better power transfer onto the wheels like lightweight flywheel, twin or triple plate clutch, LSD, torque brace, engine bushings....etc.. ofcourse the condition of your motor, turbos, ignition, fuel, intake and exhaust also factors into your output

i'm making 338 whp @ 14psi with my 99specs. pumped gas stock port and a bad slipping clutch... here's my dyno and mods.. https://www.rx7club.com/showpost.php...&postcount=248

I went with new 99 twins since I wasn't sure if my Pettit ECU could handle the BNRs. My MBC is set for about 9 psi and it feels like the old stockers powerwise (I know, I'm at 9 psi :), the new twins do seem to boost quicker.

I have a mild streetported engine.

twin turbo setup
 

dblboinger thats cool sticking with the twin turbo setup, also I agree finding what your looking for can take some time on this site

Here is my setup (my goal was to max out my twin turbo setup and keep it a street legal daily driver)
- Have my Air pump still in my car
- 3 inch downpipe, midpipe w/high flow cat(rx7 store), 3inch HKS cat back
- Apexi PFC tuned by Dee Karagiannis
- ACT heavy duty clutch, 9.5 lb Flywheel
- Redline fluids
- Efini Y pipe
- Upgraded intercooler (in stock location) one off custom job with Tial BOV welded to it)
- Aluminum Race Radiator
- Hard Intercooler piping (RE Amemiya)
- M2 Carbon Fiber Intake w/K&N filters
- Hard pipes intake(rx7 store)
- SS Clutch line
- New Fuel Filter
- Religous Oil changes
- Boost gauge and CD player(my ice JK)

I love how many people here are making these high horsepower #'s or fast 1/4 mile times and their clutch's are always slipping?:)? If the clutch's are slipping how are they putting down the power. Well there is always someone to one up you out there.
I dont want to start fights here, I was just repeating what Dee Karagiannis said "320 whp with no porting and stock twins" and he has some serious credentials http://rotarynews.com/node/view/709 he tuned that 7.86 at 169.13 RX7...enough said:)!!!

Good Luck with what ever you do dblboinger! You can always PM with any further questions

So i made 322 @!12lbs of boost stock ports and tired turbos was told if my turbos were not up to snuff and I could have made 330 easy at the same 12lbs? I dont understand why people put stock twins on large ported motors you are decreasing the efficiency and making it harder to make power by overworking the stock components.

Chris

FWIW, I have just made 343fwhp on a stock engine, stock ports with 99 spec twins, HKS DP, silenced mid pipe, Nur spec, XSP intercooler (V-mounted) , and Apexi filters, all managed by a PFC.
Unfortuantely the car came with the 99 specs so can't give a valid comparison.
Certainly seems to boost and spool very well though. I'll try to get some figures within the next few days.

eyy man im switching to the 99 spec twins too next week...wanted to knw how much boost i can safely run without the power FC...ill be getting a walbro 255 with it and an FPR so any idea how far i can take it with these mods...intake, downpiping n intercooler included...thanks!

^^^ 10 lbs and I'm not kidding

^^^^ Wouldnt take it very far without a engine management(Power FC) not worth the risk.

Chris

Its best not to bump up the boost till you have tuned it properly.

Although, per my reserch about 99 twins, just installed a set a month ago, they are ment to run 11 psi with a 99 spec ECU. however; without the 99 ECU or a PFC your really don't want to push the engine. Bad engine management equals a rolling frame. stay stock boost till you have a good management system.

This is just my 2 cents. I'm the type that believes in doing it all at one time the right way or not doing it at all.