Too much boost too quick, idea's?
 

Well my tuner called last night as they were going to attemp a few light pulls to properly tune, but ran into a little "problem".

At 2900rpm to 3200rpm (yes, 300rpm) it's seeing 10lbs of boost almost instantly, quickly get off the gas as the tune isn't right on. Removed and installed new gauge, same thing. Removed boost controller and run off just the wastegate spring (factory JGS 44mm spring, 7.6psi) and same thing, 10psi instantly.

They are fixing to take apart the wastegate to see if it has a problem.

Any idea's? Guess I engineered it decent as it makes boost so quick! lol!

What kind of dyno? Any load on it?

What tranny? My old car was a 4l60e car and it saw max boost - 9.5psi - at 3500. That's not necessarily a bad thing if the tunes right

If the boost is steady at 10psi, whats the problem ?

If I could have boost from tickover I'd be happy.

It is a DynoJet. Tuner is very familiar with boost tuning and doesn't want to start tuning from the gate with 10psi, just in case.

Wanted to start with a few psi and work our way up to 15psi.

I'll keep ya'll posted.

Gate may be a "bad" location

Add a bigger turbo!!!!

I would check your WG spring. It may say 7psi, but it may or may not actually be 7psi. All you can really do is put in a different spring.

Sounds to me like your gunna have one helluva fun car to drive though! I consider that nearly instant boost!

What I would do it double check EVERYTHING and then tune away at 10psi. Monitor all of your readings, make sure you dont have any detonation, and you should be just fine.

I agree, 10psi and up from there isnt necessarily bad. As Adam said, if theres no detonation and you're good A/F wise, it should be fine at that boost level and just tune up from there if you want to put a controller on it.

damn 300rpm! that thing will be a blast to drive!

Gates job is to hold boost from going too high and its easier to hold boost higher up .
A couple pounds higher is maybe no big deal if the engine can handle it and the tune is close enough.

Its common with internally gated cars that if you take away exhaust restriction say with big downpipe,no cat, big catback or open downpipe you can get boost numbers far beyond what you want . For example on my 91 race talon running little stock internally gated turbo just for joke until the big turbo goes on next spring. Stock boost is 10psi. I put a 3 inch downpipe on the car no cat,no catback and a bit of sound restrictor in the downpipe just to keep the neighbors off my back when tune the car in the driveway.
Anyway the boost goes to 15psi . Don't matter what the boost controller is set to.

Now externally gated setups usually have not as much problem holding the boost at lower levels.
So your gate might not be up to it or it might be wrong spring.I have no experience with jgs gates. I use tial and turbosmart with good results. They seem to hold the boost pretty close to rated spring pressure.

it seems like the waste gate is unable to keep the boost down even if you are running on the 7psi spring alone two reasons for this could be the gate you have is too small or in the wrong location.

i hope im at 10 lbs at 3000 when my kits done that would be bad asss

This is what I suspect....
http://www.taekwondoplus.org/z28/Tur...wglocation.JPG

If you go here to page 3 and page 4, you'll see Turbosmarts recommendations on optimal/poor WG orientation.
http://www.taekwondoplus.org/z28/Turbo/turbosmart38.pdf

I dont see where youve said its opening or not.. Start there..

Tell the tuner to start with very low timing and maybe even use some racegas. Spooling at 3k is not a problem...it not holding boost properly is. You have to pull the car to see where it does hold boost at.

The above picture is not optimal but in most cases it is sufficient.

Although if your tuner is concerned about a turbocharged engine building boost....maybe you need a new tuner ?

Thanks everyone for the input!

Tuner (very reputible shop in DFW tunes alot of high hp lsx's which stay together) did not get a chance to mess with it much this weekend. Shop is about 100 miles from me otherwise I would pick it up and fix it myself (trailerless). He did however say it sounds freekin awesome!! HOPEFULLY I will have some results early this week.

Tuner is not concerned with tuning boost, but is concerned about making sure the SD tune is right on. Just taking every precaution too keep everything together. Sure I want it done, but if it takes a few extra days to get it tuned right, I'm game.

I'll keep everyone posted!

I would have to agree, I think the WG is at a real bad angle, if your exhaust is flowing good (downpipe) then right on the it it will be much easier for the exhaust to continue flowing forward past the opening wastegate than to try to flow in the opposite direction to exit the WG ..

The wastegate could be too small but I'm guessing the boost was still going up on the pull?On SD I just pull all timing at 14lbs so if it does over boost it's not a problem.

For the too much boost.I'm tuning a stock 5.3L truck now and we hit 12lbs at 1800rpm(500ft/lbs) on the load dyno,no problem with the tune in there.