Someone told me they had a problem with the APS cars on stock cubed LS1's making no less than 10psi. I can't find any threads. Reason why I'm asking is we had a stock cubed formula on the dyno today that ran right up to 10psi without any loading on the dyno. This tells me it would be well over 10psi on the track.

 

https://ls1tech.com/forums/dynamometer-results-comparisons/874527-2000-z28-aps-700rwhp.html

 

In the dyno section about a month ago a member was complaining about this. He was making great #'s about found out it was pushing 10-12 lbs.

 

I use a non loaded dyno and my boost is at 10 psi and at the track it is 10 psi.

 

it hit 15 last week WTF APS

 

Yikes! We definately don't want 10psi on a stock short block.. We where lookign for around 5psi and upping it to 7psi at the track.

 

there 7lb springs in the waste gates

 

Wish I would have known that before installing the kit. I have just ordered the smaller springs, but I have no idea how I am going to get the passenger side wastegate off.

 

You should have asked

 

The APS kit was developed to make some stout power, you may have a physical size issue with the wastegates not being able to by-pass enough exhaust.

 

yea, i really wish i could get the pass side WG off as well. LMK if you find a way. I cant get the barbed fitting on the top of it for my eboost-2 and i cant get my trans dipstick in with the WG in the way as well....

 

i went with a lokar dipstick

 

do you need to change the springs if your using a boost controller

 

no, the only reason you'd need to change the springs is if you want to run a lower boost. With a controller the least amount you'll be able to run will still be the WG but you can go up to usually double the spring is a rule of thumb. So with an 8lb spring, you should be able to go up to 16 lb's.

Ill be getting the lokar dipstick as well. Did you get the firewall mount?

 

yes i went with the firewall mount the second time i think it was 36 inch on a 4l80

 

Thank you, Hindsight

 

a 7 pound spring should not be making 10 or more pounds of boost that is just crazy. My PTK kit on a 7 pound spring would not even make 6 pounds at the intake untill I installed a Boost Controller
I think the kit either has a 10 pound spring in it or the waste gates are to small.

with my Boost controller set at 0 it still make 10 pounds of boost

 

gate could be to small, or in a bad spot...

I have seen some people upgrade the wastegates on aps cars already, maybe a better wastegate would solve the problem?

good luck, Chris

 

Hmm,might be good idea to check the springs with the gates not mounted and insure they are the proper ones. Tial has them all listed on their website.

I will personally not care if 10psi is my minimum boost as have forged engine but stock guys should be worried for sure.

Also have to wonder if maybe APS has got stuck maybe unknowingly with knock off tial gates. They are out there now unfortunately. Tial also has ways to check on their website to see if they are in fact real tials or knock offs. Wouldn't of course expect the knock offs to work properly.

I am going to have to inspect my tials shortly. If you do take them apart they are under quite a bit of spring pressure so be careful they are little hand grenades! LOL Especially with 20psi springs minimum that run in my 44 mm tial gate on my 97 talon. We used a big shop vice thing to put the springs into and out of that one at buddies speed shop. Shouldn't be too bad with 7psi or so springs.

Let us know if you do check them what you find out. Would think a 38 is enough for the 20g turbos. If the boost is not 7.5 why not email Peter or APS and see what they say. Again us forged guys not too worried about a bit more boost. You stock guys much past 7psi are likely going to be buying motors pretty quick!

Oh of course its obvious but make sure boost lines from turbos to gates are on there properly.,they could blow off if you don't use clamps or small zip ties. If the line to gate is not on there or sealing good it will be like no gate at all.Remember it needs to sense the boost in the gate to open and let the excess boost out.

In fact if you don't get boost first test is to run no line to gate and see what boost a guy gets..carefully of course. You creat boost with throttle position so its not that hard to modulate it that way for brief testing.

 

Sideways I have heard of guys upgrading the blow offs already but not the gates. Not sure what other gate would fit on that setup? But we do have a few stock engine guys running think 7psi range..Huggerz??