99 spec twins...and 15 psi..need more input.
 

My turbos are going and I have a chance to get a set of 99's for a very good price. Will be running 15 psi..non-seq. I have searched but wanted updated input from anybody running these @ higher boost levels.. If I had the $$ I would go single but don't so any input would be appreciated.. Thanks..

From everything I've read, the newer twins aren't great for higher boost. Matter of fact it's common in Japan to take the "high-power" turbos off and switch to the "low-power" turbos if you plan on running a lot of boost.

15psi will likely be pushing your luck on the '99s. Again, I don't have super hard evidence, so YMMV.

Dale

SleepR1 used to run the 99s at 15psi.

If you are looking to run non-seq, why don't you look for a set of BNRs?

Probably cash driven.

yea.....id go single..if i had the $$ for spankin new ones..thanks for input

How much are you going to actually be boosting 15 psi? Once a day? Couple of times a week?

They should hold up fine for at least a few years unless you are beating on them everyday.

If you are budget driven, perhaps you should reconsider running at 15 psi....

its a weekend driver....everything is set-up to run alot of boost.. not really budget driven.. but 500 for a decent set of used as oppose to 2000k+ right now is more theoretical to me. bnrs have crossed my mind thogh..

its a weekend driver....everything is set-up to run alot of boost.. not really budget driven.. but 500 for a decent set of used as oppose to 2000k+ right now is more theoretical to me. bnrs have crossed my mind though..

Weekend driver only? I would definitely get the 99s for $500! Just make sure there is no shaft play and that the manifold isn't badly cracked, especially around the pre-control door and bridge piece. Hairline cracks are normal and acceptable, as long as they don't go past the gasket.

I had some middle mileage (about 40k) stock twins running at 15 with no issues. Other than some quirks with the sequential system itself, they were perfect. But...I ended up going single anyway.

Yes, 15 psi on the street (370 rwhp) and 11 psi on the track (320 rwhp). Loved the sequential setup!

Dialed the boost down to 10 psi when the new motor was installed way back in Oct 2004.

SleepR1, what were all your mods back then?

If they were on a engine that ever blew up they are junk and not even worth $500. I'm sure it has been which is why they are selling them for $500.

Shaft play alone wont tell you if they are good. When you blow an engine pieces of apex seal go thru the turbine wheel and kill it. The ONLY way to tell if that has happened is to take apart the turnbing side of the turbos so you can see the wheel and shaft.

There is no real difference in those turbo versus the 93-95 turbos. They still have all the same weak points.

Stephen

Good point, Stephen, I didn't think about the possibility of damaged turbine wheels. You think I would have with Bajaman's recent post! :eek:

BTW, Stephen, Bryan's making me a set of Stage 3s....you and Rich convinced me...;)

Ask Alberto...

Sleep,

good to see you stop by on the forum every once and awhile!

How's the BMW?

M3/4's great. Love the low-end torque. I see why these cars are great autocross cars. I got the J-spec twins on my old Rx7 (now Alberto's) b/c I wanted that low-end throttle response. There's no replacement for normally aspirated low-end torque on demand. Even with the J-spec twins there was that split-second waiting, and then you got a rush of power. The NA BMW 3.2-L I6 (with Dinan intake and exhaust) is very linear in throttle response, and much easier to drive at the limit. For grins and giggles, I turn the ASC off, and drift the M3 around. Pisses my wife off though LOL :)

Peace.

-M