Mechtech Owners Help!!!!!!!

[cleoent]

Hey guys, my friend guc32 and I put a mechtech stage II turbo in his car. It was boosting at 4-5 psi (vs the 7 it's suppose to) and as the rpms climbed the boost went down to 0, today we were doing about 120-130 mph in 5th and there was 0 boost. SO we un-installed everything today and reinstalled it making sure everything was tight and correct and it all is, what's the freakin problem? HELP!

[cleoent]

Hey guys, my friend guc32 and I put a mechtech stage II turbo in his car 99' M3. It was boosting at 4-5 psi (vs the 7 it's suppose to) and as the rpms climbed the boost went down to 0, today we were doing about 120-130 mph in 5th and there was 0 boost. SO we un-installed everything today and reinstalled it making sure everything was tight and correct and it all is, what's the freakin problem? HELP!

[Kevlar]

You try calling Mechtech?

[RichP]

does the mechtech have a wastegate? or a boost controller..it sounds like whats happening is the wastegate is opening prematurely as the RPMS increase.

[cleoent]

I haven't gotten a hold of mechtech just yet.
I've been trying.

Also rich, how would we stop the wastegate from opening up prematurally?

[jsp98m3]

There is no wastegate.

[cleoent]

Originally posted by jsp98m3
There is no wastegate.

Hmm, jim any ideas that you can offer?

[jsp98m3]

In general with the design of this turbo it's not unusual to see a fallback in boost at steady high rpms. This type of turbo is extremlel fast on climb and gives phenomenol torque and HP at lower rpm. It isn't optimized to be a high rpm air pump. A classic turbo with a larger input than output is better at this. So I don't know that your 130mph jaunt is something to be concerned with.

Guc's other emails to me sound a bit like the tubing and perhaps orifice's on the boost sensor as well as the intake supply pipe, are undersized. But I can't tell without fiddling with it in person. I'm not that good :)

I suggest that you find a local tuner shop that deals with turbos. While the VATN turbo is different in many respects, they have the best chance of helping you out.

[cleoent]

Originally posted by jsp98m3
In general with the design of this turbo it's not unusual to see a fallback in boost at steady high rpms. This type of turbo is extremlel fast on climb and gives phenomenol torque and HP at lower rpm. It isn't optimized to be a high rpm air pump. A classic turbo with a larger input than output is better at this. So I don't know that your 130mph jaunt is something to be concerned with.

Guc's other emails to me sound a bit like the tubing and perhaps orifice's on the boost sensor as well as the intake supply pipe, are undersized. But I can't tell without fiddling with it in person. I'm not that good :)

I suggest that you find a local tuner shop that deals with turbos. While the VATN turbo is different in many respects, they have the best chance of helping you out.

I got a better idea, how about you make a trip up to san jose (only a 8-10 hr road trip) and help us out? Probably not right? Well i'm going to call mechtech right now and see what they can tell us. Yesturday we had a small race on the freeway between his turbo m3 and my 325i with chip, he was unable to pass me on the freeway, somethin just doesn't add up, i dont think he can live with that type of performance for the money he spent!!!!

[jsp98m3]

No, that would definitely not be right. I think my car was always slightly faster than a 325i with a chip. Even at low boost.

[cleoent]

Originally posted by jsp98m3
No, that would definitely not be right. I think my car was always slightly faster than a 325i with a chip. Even at low boost.

That's when we noticed the problem. I had two people, he had no power to pass. Well we have one possible cause, there is a house barb on the actuator side of the turbo that is not threaded in all the way, i believe a valve of some kind connects to there... maybe that's it.

One more question, if we are not able to but in all the nuts and bolts to the exhaust manifold (we are missing 4), will oil leak out of there some how?

[jsp98m3]

On the exhaust manifold you really must get them put back in. You will have problems. Thread the nuts onto an appropriate sized bolt and go to them with a grinding wheel and shave the seat off of the nuts if you have to. You are likely to toast a valve without them. If you can't get them on, pay someone to do it. Hot gases escaping around the exhaust header is not good.

[cleoent]

Originally posted by jsp98m3
On the exhaust manifold you really must get them put back in. You will have problems. Thread the nuts onto an appropriate sized bolt and go to them with a grinding wheel and shave the seat off of the nuts if you have to. You are likely to toast a valve without them. If you can't get them on, pay someone to do it. Hot gases escaping around the exhaust header is not good.

Thanks jiM! We'll get it fixed!

[cleoent]

Ok good news! After speaking with mechtech seems we had some vacum hoses wrong, now it boosts to about 5.5/6 psi and then dies down to about 4.5..... does that sound normal? Never below that even on the freeway.......

However a new problem has emerged, the car is overheating..... Thermo and water pump seem to be working ok, any ideas?

[jsp98m3]

Verify that the auxilliary fan is operating. You may be running lean. Check that fuel pressure boost is working (vacuum). This is extremely important.

[cleoent]

Originally posted by jsp98m3
Verify that the auxilliary fan is operating. You may be running lean. Check that fuel pressure boost is working (vacuum). This is extremely important.

Thanks Jim! We'll take a gander and get back to you tomorrow.
Leo

[guc32]

Blown head gasket is the problem. I dont know what else my be wrong till monday when the machanic do a compression and leak down test. Crossing my fingers hoping it wont be anything else.

Jim, did you get your internals fixed. If so, did u go stock or after market. Like JE pistons, total seal rings, and Pauter rods. If i do need to fix the internals, what compression should i run now to raise my boost? 8.5:1 ????

[cleoent]

Originally posted by guc32
Blown head gasket is the problem. I dont know what else my be wrong till monday when the machanic do a compression and leak down test. Crossing my fingers hoping it wont be anything else.

Jim, did you get your internals fixed. If so, did u go stock or after market. Like JE pistons, total seal rings, and Pauter rods. If i do need to fix the internals, what compression should i run now to raise my boost? 8.5:1 ????

E, i knew you would find some way to make the best of a bad situation, time to upgrade the inside so that you can run more boost! I like your thinking.....

I think that running lean was the problem for sure, because when we were on the freeway and all that air was getting to it no prob, when we got off freeway it heated up. Hmmmmm...

[jsp98m3]

I went 8.5:1, custom oil ring grooves, larger oil ring, .040 deeper valve pockets so there won't be any bitch slappin on accidently downshifts. Total Seal and all that stuff. $1,000 including tax.

Stock BMW POS is $1,700+

Go JE if you need them. The stock rods are good to close to 1,000 horsepower. No need to upgrade those unless you want to go lightweight and up the revs.

[guc32]

Coo thx Jim. Ill do the JE if have to. How much boost you running now? Are you goin to do a right up one those pistons on your site?

[jsp98m3]

I might if I have time. But basically my car will have taken up the center rack position at the shop for 3-4 weeks when I get the pistons. I think they are going to be in a hurry to get the car back together when the pistons come in. If I have nothing to do I will hang out and do some documenting. But it's fairly certain that I'll be in the middle of this DDE thing to the point that I will just pay the bill and never see it done.

[guc32]

Jim,
did you have to special order those JE pistons or was those made for an M3? If you had to special order them, would u mind if i got the specs from you if i had to order mine?

Thx Yih-Woei

[jsp98m3]

goto: www.racetep.com and call them. Mine are still in the engineering department at JE since they are custom.

Call and see if you can tack your order on with mine.

[guc32]

How much HP and Torque will you think the car will run NA on 8.5:1 compression? Will the engine lose a lot of power, but then gain it with higher boost?

[jsp98m3]

It will lose some power at low rpm of course but make it up with higher, safer boost. On pump gas

[jsp98m3]

PS: I caution you...

Do not follow in my footsteps on upgrades blindly. I'm in the middle of my second motor rebuild in two months, fiddling with things.

This is not my daily driver and I can afford a new motor or monthly rebuilds.

What I have done or will do to my car is not always what I would recommend to someone in another situation.

I personally think that the piston change will be quite beneficial even at moderate boost levels of 8 or 9 psi. But every car is different and while I generally publicize what I do to my car, even mine breaks eventually.

I just wanted to add a little disclaimer to seek your own counsel on major motor modifications. I intend to try for 500 hp. This will not make my car the most reliable car in the world and it will not be a good track car anymore in many ways. Since I'm planning on buying one or two new cars within the year to supplement the ones I already have, this is no big deal to me. But please think things through carefully for your situation.

[guc32]

Aight coo i will. Thx Jim.

[Bob ///M3]

Bump!

Bob ///M3