And people give 99' pistons such a bad rap. Basically I think it comes down to the overall health of the subordinate systems and a bit of luck. You can have a stage 3 Vig go on in great health and you can have a bone stocker devour a piston.....its hit or miss.

 

That is very unfortunate!

Good thing the bore remained in good shape...I almost don't even want to hear what tuner the tune was from :-?

 

More reason to love my B234 motor. I know that those pistons are only good upto about 300 hp but theres no way that guy was running that much on stage 1 setup. I'm willing to bet it was a bad piston from the supplier that finally gave, kinda like what happend to me only with rod bearing.

 

More reason to love my B234 motor.

x2 Screw t7.

 

t7>t5 ftw!

 

I don't think so. A MAF sensor is wasted on a turbocharged car if you ask me. MAP is all you need and one less sensor that fails when its a tuned car. And T5 FTW in a 96 to 98 9k because theres no TCS getting in the way of the fun. Reactive engine management system kicks ass and a proactive system like T7 sucks cause it gets in the way.

 

Hmmmmmmmm maybe future project.......T7 car with b234 and switch to T5 software........reliability and easy power in one, can't beat that. I predict this will become the future. Just like the people who like to drop the b234 into ng900 and c900. I would say that the Saab B234 motor is to Saab what the Nissan R34 Skyline motor is for them.

 

to tell you the truth this is why i like t7 better. for example, mike saunders and jrbrangi both have gt30's of some variation on their ng900's with b234 blocks....and they say that there is very little way to predict when/how boost builds. and its just nothing, nothing, bam 30+ psi. both are running t5, and iirc, both have said at one point or another that they liked their old setup, or wouldnt mind de-tuning it a little bit. both those cars are daily drivers.

daveship has a gt30 variant as well, in his 9-5 with forged pistons, etc, etc. he will tell you that it is very streetable and he daily drives it. boost is very predictable, and comes on quite smoothly for what it is. dave says it drives better than the car did stock, until you get into it, and then its just fast, but not unpredictable fast.

t7 seems to be the way to make nice smooth power off of a huge turbo, while still maintining streetability. ive had people in my car that were reading a book and after a 3rd gear pull, when asked if they thought it was quick, a not really was spoken. once told to watch the speedo and surrounding things like trees, they said a completely different comment. and i dont even have a monster turbo. just a td-04 15t....


sucks about those pistons though. that just looks harsh.

 

to tell you the truth this is why i like t7 better. for example, mike saunders and jrbrangi both have gt30's of some variation on their ng900's with b234 blocks....and they say that there is very little way to predict when/how boost builds. and its just nothing, nothing, bam 30+ psi. both are running t5, and iirc, both have said at one point or another that they liked their old setup, or wouldnt mind de-tuning it a little bit. both those cars are daily drivers.

Boost is a lot more predictible when there's a knowledgeable driver behind the wheel. That wasn't me six months ago. Having that much power was pretty new, so I was learning the car...sort of adapting the same way the ECU does.

I'm pretty well adapted now....

My impression is that there's not much difference in the way boost builds with T5 vs T7. There's a certain RPM threshold that enables enough pressure to build, then Wheeeeeee! The onset of boost wasn't much different between my car and Dave's 9-5, with the only major difference that Dave's larger 3076 spools about 500-800 RPM higher than the 3071. (3800 vs. a little more than 3,000 RPM) That also could be because of the small (.63 A/R) exhaust housing that we're using on the GT3071s....

What's immediately noticeable is that Dave's car seems to have a much more refined application of power, probably for a couple of reasons unrelated to T7:

-- He's got an external wastegate, which enables the turbo to manage high boost better than an internal, and is better at evacuating the excess exhaust gas hitting the turbine wheel. (Even though I ported my wastegate, it's not as good as an external one...) It also seems to reduce some of the peakiness of the torque curve and put more area under the curve at higher RPMs. I've seen dyno sheets from modded Viggens and 9-5 Aeros with stock manifolds and they look a lot like mine, so I'm not sure how much T7 plays in this.
-- He's driving a 9-5, which doesn't show torque steer nearly as much as the NG900/9-3, so the perception of wild power onset is reduced. When the power is on, the 9-5 isn't anywhere near as butt-pucker inducing. That's the kind of predictability I want...

If I could find a 9-5 with a blown motor for dirt cheap, I'd consider dropping the B234 in there and using T7 with no problem. The main issue I have with T7 cars isn't the engine management, it's the dog shit hardware in the engine itself. Combine a crappy PCV system with a crappy oil pump and crappy pistons, and the result is going to stink, as evidenced by that picture in the first post....

or...the other option is to build up a rock-solid B235R motor with forged internals and better breathing, like Dave did. I'd have no problem rocking that as my daily driver instead of the NG900....

 

eh, I just ignore the dead rear o2 signal and I like OBD 2 ability to more closely define a problem if it triggers a DTC. I thought all 9k 93 through 95 had TCS. I know there was an on and off switch available but its still there.

 

eh, I just ignore the dead rear o2 signal and I like OBD 2 ability to more closely define a problem if it triggers a DTC. I thought all 9k 93 through 95 had TCS. I know there was an on and off switch available but its still there.

TCS was std in 92 and 93 9ks (turbos) and optional (w/switch) on 94 and 95 Aeros. Discontinued for 96+

My 1995 CSE didn't have TCS.

Back to the topic at hand....I agree with Nick on that last point. His car is definitely quick....nice and smooth...whereas my 9000 is more on/off. He's definitely right about the boost coming on real fast with T5. I guess each has their pluses and minuses....I'd rather have not so smooth power and non-weak pistons.

 

I guess it just comes down to what you like. I've driven T7 cars and while yes its fast I don't like how it feels and manages the engine. I like my torque spike and turbo rush that T5 gives me. The rest of it comes down to liking the ECU reacting to me only, not reacting to what I want it to do only to dial it back for traction issues or gearing. If I punch it I wan't it to go, tire squealing or not.

 

not reacting to what I want it to do only to dial it back for traction issues or gearing. If I punch it I want it to go, tire squealing or not.

see thats the thing, unless a t7 car has TCS. its not going to cut back power because the tires break loose. I'll tell you, if i nail it in 2nd, tires lite up and break loose. 3rd they stay planted and it goes.

to me it sounds like you just don't like TCS!!

you want a clue, i'll get you one. cooper and myself used to have an ongoing race between us. 50-90, cars would start together and end together. but i would get a little jump, then he would slowly reel back up. this was untuned 9-5 with intake/exhaust and ng900 set with exhaust and mbc at 15psi.

if we had dyno'd them, they probably would have put down very similar numbers on the dyno. does that disprove your "punch it and go theory"?

if you want, ill get a passenger to record video of me making a pull in 2nd gear, 2000rpms, to the rev limiter at 6400ish. you will see your punch it and go whether tires squeal or not

 

Very interesting to see Nick. People always talk about "t7's blow up." Well now I have something to picture!

 

I drove the new 9-3ss when they came out and it was a manual arc. Punched and it just didn't have that feel that I look for.

Your right, I hate TCS, along with the other elctro gizmos with the exception of power steering and abs brakes, the rest of it I stay away from.

I had thought all t7 cars had tcs built into the software; my bad if I was wrong on that.

 

I drove the new 9-3ss when they came out and it was a manual arc. Punched and it just didn't have that feel that I look for.

9-3ss 4cyl is T8....not T7.

 

ahhhhhh................so i guess i need to get my hands on a 9-5 that I can test drive.

 

yeah..i'd do that. t7 is different than you think. and 99 viggens and 99 9-5's dont have tcs. i dont know about the rest of the t7 cars though.

tcs is what you hate, not t7. i have never experienced t8 firsthand, so i cant tell you.

 

Now the trick will be me getting somebody to let me drive a 9-5 the next time I'm home lol. Dealership knows me to well lol.

 

ill take a video later today if it stops raining and the pavement drys out. if not, i will do it tomorrow. might not be the same as a test drive, but it'll disprove that punch it and go theory.

 

Cool. Yeah when I drove the 9-3ss when they first came out there was no boost spike or anything. It was just smooth and even...........not so fun as you just couldn't feel it without looking at the guages and everything outside. I love being able to feel the speed too.

 

my 2000 doesn't have TCS either...I think after 2000 TCS was used, but u can obviously turn it off

 

T-8 is extremely smooth...it gives you an initial kick in the ass, but as it continues to pull you can hardly feel it

 

Some things I forgot to add is that it has been tuned for years with no apparent problems.

My best guess is that due to the huge amounts of carbon buildup that the failure is related to the crank vent system. It had one of the previous fixes and has had blow-by related problems for a while.

Most of the other piston problems we see in these is related to oil starvation or obvious pre-igntion melting and the subsequent galling in the bore. This is the first cracked piston without obvious major cause.

 

Man I thought my 2.0 looked bad when that rod bearing let loose...I had nothing on this thing!

It had one of the previous fixes and has had blow-by related problems for a while.

Hey Nick - could elaborate on these blow by issues...I might be on the phone with you a little later on today - time to order some new toys and ask some more questions.

 

Just as a data point, my 2000 9-5 Aero has TCS.

Didn't they go "all the way" to ESP - system-wide stability control, in like '02 or '03?

 

I think 2001 and 2002 Viggen's all came with TCS but can be turned off.

 

I wish I kept my old 9-5 engine for investigation. It blew up on the race track two years ago, and the conditions were awfully similar - stage1 from "another" tuner and one of those intermediate PCV fixes (whatever was current in 2004).

*Sigh*

 

ive still got what i think is the original pcv system on my car and it has not shown any problems. i dont think i'm gonna worry about upgrading it as i cant see a reason to. if it aint broke, dont touch.

 

Um, you want it.


The PCV update kit is 50 bucks from the dealer and worth every penny. The indy shop in my neck of the woods has done quite a bit of testing, and this makes a big difference.

 

yikes, you should replace that original PCV system ASAP. just about every single component in mine was totaly shot.

 

does your pcv check valve hold vaccuum? if not, youre blowing boost pressure into the crankcase - not good

 

and plus, I don't think I have ever seen a check valve in a turbo car that's lasted more than 5 years. boost in the crankcase will blow seals, make the car run rich and possibly cause a host of other issues. If you don't replace the PCV system, at least do the check valve (if you can get it off without it breaking to bits)