every time i sign on the boards julian is always having to defend himself ive never heard anyone say anything bad about his shop ever.

 

im not saying anything about julian or MRC, as far as im concerned they are a trustworthy shop that does great work. im just amazed that all their APS single turbo kits hold boost considering almost every other kit, installed by other capable shops, dont.

like i posted on the last page, my boost is doing exactly what the boost in that graph does, peaks to 10.5 and then drops to around 8.5, i posted pics of my datalogs as well. but the only difference is that my 15psi spring is all the way down.

one thing i noticed in synth19s pics of his kit, is that GRD installed the stock actuator rod on the Forge canister. ever since i installed mine, i was apprehensive about Forge not having the length right. i wonder if thats the case, maybe mine is tightened all the way, but in reality its because the length of the rod isnt right.

Julian, did you guys use the Forge rod or stock one? was it you or somebody else that said you had to cut off some threads from the rod?

 

Tig,
We have made no modifications to any of the stock actuators on any of the single turbo kits. I honestly am suspecting a boost leak somewhere, perhaps at the manifold on your car..Do you have an aftermarket plenum or spacer??
As far as our installs go, we have seen other shops that claim to be experts in APS installs, overfill the APS oil pan to the full line, when it is common knowledge that the oil level must read at the low mark or just above. This was a bulliten that was sent out to all APS dealers over 2 years ago..The shop that did it was not one of the shops mentioned on this thread nor were they MY350Z sponsors..But my point is, not all big shops are as compitent ans one would think FYI we installed the first APS TT kit in the USA and actually helped make changes to their instruction manual, and from time to time GRD, who we work closely with, have been known to contact us for some troubleshooting, and vice versa..I can not understand why alot of single tubo kits are not datalogging boost at a steady rate, but I can say that the ones we have done, we without issue.
The boost drop is 99.9 pecent not turbo related, but related to restriction, boost leaks, wastegate issues, ect...We have seen boost drop off on one TN kit that was simple as the BOV sping tension being to loose and was opening up at 5 psi..This very well could be your case..

 

i have the aps plenum, but i pressure tested the system, held pressure, 20psi to be exact for 10 minutes. i did this by placing a coupler sealed to a pvc joint, with a pressure gauge and air feed, and connected it to the turbo inlet. no leaks anywhere. there was some sensor on the tb that was going crazy clicking, scared the hell out of me. i recently changed the bov, i had the aps bov, now i have the greddy type rs and its tightened about 3/4, to hard.

i have the blitz sbd-ic, the boost still drops a little, probably 1.5psi by redline. i even tried it with the bc off, just going on spring pressure and it still drops, with the 15psi spring 100% cranked down.

 

Your saying down under as if its a negitive point.

 

That is strange...I would love to examine your car, however your way far away..If your ever in the NJ area for some strange reason,feel free to stop by and we will have a lookie see..
On a side note, what kind of HP you making??You could catually be experiencing valve float during the upper rpms,if the power is dropping off..A stonger valve spring would help this..Could be something to look at, however Im not saying thats the issue..

 

i appreciate you trying to help trouble shoot, always helps getting different opinions. on sharifs dyno with no correction my numbers were 330hp and 405tq. my last DJ was 380hp and 410tq. i hope its not valve float, if so that problem aint getting fixed no time soon. i can live with it. like i said its getting better with fine tuning the boost controller and tightening the actuator.

 

Which tells me it is related to not holding the boost, not a bad turbo...

 

i agree, i never said it was a bad turbo, just too restrictive housing, which is s symptom, making boost, but not holding it. BUT when i turn the ebc off, it still doesnt make and hold spring pressure. i also realized that the forge actuator isnt right, they sent me one with the wrong rod length, so im thinking the tension isnt right causing the preload on the actuator to be low. they are sending me another.

 

i had my APS ST installed at MRC, and let me tell you, Julian and the mechanics there know everything there is to know about our VQ motors!. I can confidently say that they did an AMAZING job with my car. I have had the turbo on the car for a good ~16,000 miles and it runs like the day i got the car. Every time i go to get an oil change he checks the car over (nothing ever needs to be touched) *knock on wood. And as for the boost drop, i had it SLIGHTLY with the stock exhaust. As soon as i put my cutout on it completely went away.
-Eric

 

do you have a pic of exactly where the cutout is, i bought a 3" electonic one, but im trying to decide on where to put it, kinda thinking about right past the WB plug, right at the beginning of where the S-pipe is. thanks.

 

The cut out would go in the exhaust pipe, prior to connecting to the stock exhaust..

 

im putting mine much closer to the turbo than that, probably less than a foot downstream.

i changed actuators last night, didnt seem to change the boost drastically.

 

There is a video on APS's website on how to properly set the actuator tension.I would link it but it wont work on this site..lol

 

I had an aps st install completed by japtrix last week and i'm happy to say there is absolutely NO boost drop. I'll post a thread with all the details in the near future. I just thought I should chime in!

 

i mean i tried a different Forge actuator, for some reason they sent me one with the wrong rod length so they shipped me a new one, i was thinking it wasnt right because the rod was too long, but it didnt help. im gonna try to adjust it tonight and log some runs.

 

post it soon, how about some more details, actuator, exhaust, etc...