donny

My rear turbo is getting bad. leaking oil and the shaft is pretty loose. Are the 99 twins really worth the extra money or should I just have these rebuilt?
From my understanding the 99 twins are only good for about another 25hp, but not sure.
I will eventually go single, but am going to stay with twins for now.

donny

any one? And do they come with a new exhaust manifold?

TireSmokin7

I think the best bang for the buck is the BNR stage 2 if your turbo isn't cracked too bad. 17 to 18 pounds boost is nothing to sneeze at for a car on pump gas.

Steve

911GT2

No.

user 9348703

Not really, but I dont agree BNR would be any better.

What are you looking for long term? Short term?

Single? If not I would go with stock twins again

2-Rotor

From what i understand they have better flow through out the turbos themselves but if you do not change to the Efini "Y" pipe and a less restrictive exhaust system the 99 turbos wont be any improvement. Ask SleepR1 forum member for more info on the 99 twins.

rynberg

The 99's spool even faster and earlier than the stock twins. If you need a new set of turbos (and manifold) and don't plan to be running over 15 psi of boost, they're probably worth it.

Certainly not worth upgrading to if your current turbos are ok.

DMRH

The series-8 turbo's are an improvement on the previous versions.

With the slightly smaller internal diameter housing, they do spool quicker as suggested.

However they will let you down if you try to boost past 1-bar for regular driving.

Max'ed out. they are good for 16psi before you kill them in a matter of weeks.

Keep them at 12-psi (max) & you are good for years of reliable operation.

Find the super rare "Bathurst" twin-turbo's & they are good for a reliable 18psi. Made for the Aussie version by Hitachi. They did just 100 & about 15 sets came down under. The rest...........??

Who knows.

Japanese customers perhaps.

user 9348703

Bathurst is rare?

You sure you dont mean SPIRIT R?

RX7SpiritR

iTrader: (1)

who knows anymore.....

MAZDASPEEDS FD3S

Just go single turbo!

rceron

I think a new set of 99's cost about $2500. If you plan on going single save some money now and just buy a used set of twins for $300 just to get you by till you make the big purchase.

If you have a way around emissions constraints then going with a small single turbo (or whatever size makes sense for you) seems to be a better "bang for the buck" move than expensive 99 twin turbos.

R

XSTransAm

Are you sure the 99's spool quicker? or is it just that they j-spec cars dont have cats in there dp's?

KevinK2

From SAE article in 9-99 about new rx7:

The 99 spec has smaller dia (50 vs 51mm), wider, more efficiently bladed turbine wheels for quicker spool up, and a bit less backpressure. The compressor wheel runs tighter clearances to housing for up to 80% efficiency, vs 75% before.

Vs the 96-98 FD, hp went up from 265 to 280 hp. Boost at max hp went from 9.1 psi to 10.8 psi, which imho was the main reason power went up, but freer exh and new ecu helped too.

http://www.rx7.net.nz/newrx7.htm

911GT2

They are an improvement, I agree. But they are not worth the $3500 asking price. I mean I can buy two sets of BNRs for that price, and have more efficient turbos that will last longer (cus I'd have two sets )

2-Rotor

You are right. However the only reason i personally would go with new twins is because the housings havent been stressed or cracked yet. I am sure if your housings arent cracked too badly then to go the BNR route would be a good move as well. It all comes down to preference and what your looking to do with your car.

racer1

Actually they doesn't worth their money. I have the 99 specs but after driven older FD's, there is not much different. Go with BNR's or go single.

huffner

99's will last longer because of their design. Read up on them and you will see. To long to explain. Also BNR's are a waste of money IMO. They smoke like spy hunter.

azndisgrace

a bit off topic but whatever happened to M2's ball bearing twins?

dubulup

Ask Artguy about tuning.....

donny

Before I pulled the engine I checked the boost levels at full throttle and I was getting full boost just fine, and the car ran like a top. I am getting a little more oil in the intake piping then I am sure is normal and there is a little oil drip hanging from the rear inlet up pipe, but nothing major. It never drips on the ground. I was mostly concerned when I felt how much play was in the rear turbines' shaft. Apparently, according to a very good shop in TX, when the turbos, are actually spinning they center themselves and are just fine. So, really I am probably ok with these for a bit longer. I just dont like the oil in my intake pipes.

Does anyone use a "Oil catch tank"? Like a Greddy or similiar. Are they easy to hook up and do they really keep the oil out of the intake piping??

artguy

I am very happy with them. I am not done with tuning and put down 381rwhp and 320lbs of tq.

www.conceptart.org/dyno is where my dyno sheets are located. notice how choppy it is up top..as well as the power drop off....running way too rich up there and timing is very retarded for safety reasons. that should be all cleared up soon. my car is going to spend some time at gotham to finish it up.

I would get the m2 set before both the bnrs and the jspecs. my set has a lot of hard miles at 16-17lbs of boost and I have no problems with them at all. they are cherry and were worth every penny.


j

dubulup

stock manifold?

TireSmokin7

Before we bash all BNR turbos for the smoking issue it needs to be mentioned that the only model that had that problem was the stage 3 with the 4mm shaft and dynamic seal without the new banjo bolt Band-Aid. That turbo is no longer available! The stage 2 has the same turbines/boost capacity and NEVER had a problem smoking and is quite a bit cheaper. The new stage 3 will have a 5mm shaft for increased longevity (over all stock Mazda twins) and better fit for the dynamic seal hence, no spy hunter smoke trails.

Steve

Zyon13B

I got a Greddy one, it works great. Almost all oil is kept out of the intake. I notice a tiny bit, but it could be left over from before I installed it.
Pic.