Im getting ready to build a block for my APS TT, we are going to try to upgrade the housings if they physically fit. My goal is ~600rwhp on pump with meth since Jon@Z1 recently tuned a APS TT and made 593 with stock APS housings and no meth. I want to keep the car streetable since i dont necessarily require to daily drive it buy it does get driven alot (currently @99k miles). Right now i dont plan to sleeve the block and do a pretty basic build but im trying to decide on cams and compression.

Ive talked to JWT and they say for over 580rwhp i should use C8 or C9 cams (the other APS car made 593 with C2s) and for C8s i should set idle 800-900 and C9s 1k+. Since a more aggressive cam lowers an engines dynamic compression i want to know if i could get away with slightly higher compression than the common 8.8:1. And also i believe a higher static compression would improve the harsh idle from the cams.

I want your opinions on going with atleast a 9.5:1 piston with the APS TT and aggressive cams since it is only efficient to a relatively low 15psi.

What do you think? should i just do the basic C2 with 8.8 compression or try one of these options? What do you think about GTM cams? does anyone know the reasoning behind the staggered durations?

Thanks,
Rob

 

Ive noticed over the years most everyone goes 9:1 CR on TT builds. For my next one, Im gonna go 8.5:1. I wouldnt go the way you are contemplating. Many will tell me it wont make a big difference, but these VQ's can be finicky, and IMO, anything to help fight detonation, especially for those of us with tunes that push the limit would help. Id rather run a little more boost and conservative tuning and make the #'s than lower boost and throw tons of timing at it.

I have never been impressed with any JWT cam, even though I had the old school S1's, they were midrange only cams.

I have however made sick numbers on the BC3's and seen the same results minus the $hitty idle out of BC2's, so Id go for one of those. My TQ curve is a plateau and my HP graph looks about as good as it will get on a stock plenum, no other headwork, and relatively small turbos.

 

+1 to Alberto's advice He speaks from experience on the matter, so I'd listen to his wisdom. Running more than 9.0:1 compression to achieve 600whp is a recipe for disaster and a short lived motor IMO. Upgrading the turbos would be a much more sensible solution.

8.5:1 compression is safer for turbo apps on a VQ. I also recommend the BC Stage 2 cams over the JWT cams being considered.

 

See Im not just an a$$hole that laughs at dreamers, non drivers and lazy people that dont search! I still have it in me to help a brotha out

edit-just for reference on my built longevity:

9:1 @ 525whp mostly = 9000 miles then boom

9:1 @ 605whp mostly = less than 5000 miles then click, click, clank, boom, fawk me

Give me 9.5:1 or 10:1 @ 400whp Id blow that $hit up in less than an oil change interval in any major shop owners face, especially GTM.

 

well thanks for the advice, so should i go with a stage2 or 3 cam? I just dont want a crazy cam that shifts the powerband way right were my turbos are running out, a stock APS kit starts to run out of breath at ~15psi, so assuming i cant physically fit bigger housings which cams would suit that setup best?

and also do you think that the APS kit needs other modifications besides the housings? enlarge the charge piping? anything like that? Im not looking to change TT kits but i want to milk the most out of what i have

Thanks

 

The APS power limit is not that far off of a Greddy kit. While I have no experience on an APS + BC cams, I can tell you that with my car and another Z with the same TT kit as me, same tuner, same dyno, same boost levels, the BC2 cams were almost (im tallking less than 10whp) identical power per psi as my car with larger downpipes and BC3's.

We saw this from 10-20+psi. I had to flash my ECU to raise my idle (fawk dealerships and consults) and still my idle is "sketch" although if you like the lope you would love it. I'll post an idle vid if you want to hear it on a good day once warm and smoothed out.

IMO the BC2's and open up the exhaust as much as you can, you should see your goals.

 

yea i would appreciate that video, right now i have the 3.5" downpipes and 2.5" exhaust but will be switching to a 3" exhaust.

im running Osiris so bumping the idle wont be a problem either way

 

My bad I thought the car was warm when I did this but it was cold. Hearing it online or in person you will probobly love it. Living with it and sitting at lights all the time with a loud a$$ exhaust you may hate it. It fluctuates so much I try to not warm the car up too much to not p!ss off my neighbors lol.

http://www.youtube.com/watch?v=22_KmWEEGrk

 

I don't see why you shouldn't be able to fit larger housings. The larger turbos of the APS Extreme kit fit in the same location as the standard APS kit. Have you considered upgrading to APS Extreme components? You would easily reach your power goal if you swapped in the larger turbos, 3.5" downpipes, and external wastegates of the Extreme kit.

Edit: I see you already have the 3.5" downpipes.

 

I think going to the Extreme though would move that powerband further right than he wants. Certainly more up top than the cams alone would do.

 

those kits are pretty hard to find, and i would really like to stick with my current kit, im not sure that the overall size of the turbo is much bigger but since they are external wastegates you get more turbo in a smaller space, im going to try to atleast fit atleast regular GT28 housings but im to plan my build as if they wont fit since even if they do i have no idea how the housings will affect its characteristics .

on a side note, would you trust Eagle rods at 600rwhp? i already have a set but considering upgrading, i would either way if money wasn't an issue

 

i didnt buy this kit to go for CRAZY power, but i don't want to settle for 50% for what the kit is capable of (especially after reading the whole "What has happened to the FI forum thread") i just want to get the most out of what i have, hitting a certain number isn't really what matters to me its know that i extracted its full potential, and that's why looking into the larger housings, because its pretty well know that they are the bottleneck of the APS kit.

 

I would trust Eagle rods at 600whp. They have more than proven themselves in this community on many builds.

I actually cant think of anybody sharing a bent/broken aftermarket rod off the top of my head. Not counting people who have had oil starvation/spun a bearing then bent the rod.

 

That's what i thought, until i saw this post by Srt8dum https://my350z.com/forum/8720032-post23.html
which i know he says that was at 700rwhp and im only planning on ~600rwhp but i like a little room for error

i cant tell if the pic is still in that post or not since im at work

 

Yeah, that’s the only complaint/issue I’ve found on Eagle VQ rods too… I’m seriously considering Eagle’s for my build; I’m shooting for 550 whp on E85 with the PowerLab GT35R.

 

Here’s the other brand (K1) that’s getting some serious consideration by me:

http://www.z1motorsports.com/350_g35...3c52322be28c00

 

I see... Consult with Blouch Turbo. They have experience modifying the standard APS turbos and can probably answer your questions. Talk to Chris (Cass007) too. He had Blouch modify his APS turbos. Hopefully he chimes in here.

 

Thanks
i didn't realize that anyone had been successful modifying them, not sure which you consider the standard APS turbos (the nonGarretts i assume?) i have the APS Premium Ball Bearing kit. Hopefully Cass007 will chime in if not ill send him a PM

 

Hey Alberto, How have the BC's come along in QC lately? I've seen some threads in other platforms (Non-VQ or Nissan) state the BC cams were as much as 10 degrees off after degreeing them. That's way to much, especially for a VQ that depends on the phasing to find horsepower.

 

I cant answer that as Ive only dealt with em on my motor and the results speak for themselves. I hadnt heard of QC issues from BC until now.