G3po

iTrader: (8)

A bypass valve is adequate for low boost and quiet operation.
It is also easier to get Carb approval with a Bypass vs. BOV.
It is good that JWT chose two valves one fro each turbo = more potential vent volume. Also since JWT is "pulling" thru the MAF, a bypass method is less disruptive. The alternative is "pushin" thru the MAF which is the method deployed by Greeddy , PE, and APS.

However, a BOV is more efficient for venting at higher boost pressure (say >8psi). However; a BOV can be rather loud, some tuners like the sound, personally I prefer stealth.

If a BOV or Bypass can not adequately vent boost upon rapid TB closure, the shock wave can stress the Tutrbo compressor or minmally bleed some of the "spool" off. In ralley raceing were rapid "on-off-on" throttle modulation is the norm , you want to keep the Turbos spooled , which will improve throttle response during the "on again" cycle..

The best of both worlds is a 2 stage BOV such as that offered in the APS kit. It acts as a bypass under low TB maneuvers and a BOV under agressive throttling.

kjbalto

Thanks for the info G3po. JWT claims that they will have more ecu flashes to turn up the boost once you upgrade the internals. I do like the intimidating sound of a blowoff valve but I can also see myself getting sick of it after awhile. I tried to look up the differences of the blow off and bypass valves myself and I came across this...

Whether you decide to vent/wooosh to atmosphere with a BOV, or quietly back to the turbo compressor with a CBV depends on your injection system. Magazine test results over the years have shown little performance difference between the two, other than an interesting aural sound. The reason for fitting one is to reduce strain on the compressor turbine wheel, the intercooler, hoses and fittings.

G3po

iTrader: (8)

If JWT does use twin Bypass valves, it is highly possible to replace each of them with a dual stage BOV. However; on eside effect is that wehn the second stage vents atmospherically , a brief "rich" conditon will occur since the "pull thru" MAF will have calculated Air mass based upon an unvneted pipe. So went the BOV releases Air mass into the atmosphere , the A/F ratio will brifly drop. Depending upon valve placement this may or may not induce "stumbling".

I am building a forged bottom end at this point, and the main issue I see with the JWT setup is that the Turbos and ICs are on the "smallish" size. I have considered the posiblity of upgradeing the 530BBs to 700BBs. Both offered by JWT. Currenetly I am more swayed to APS.

It is also not fully celar how JWT is fueling the kit.
I would hope he adds larger injectors rather than
a rising rate regulator. Either method can be controlled via an ECU re-flash , however the Rising rate method has it's long term reliablity issues. aka it's not ideal to operate the injectors above ~58psi for long.

notnser

Having worked closely with JWT on my project I am CETAIN they will not use a rising rate regulator, they will find a way to use larger injectors.

kjbalto

Just to give an update on the JWT kit. I called them on Friday and asked them when they expect it released for the G35. They said by the end of the first quarter which is end or March. The guy I spoke to didn't seem to know much because I asked him if they are doing ecu flashes or a standalone since somebody said they may be using a standalone, and the guy said "It will be a complete kit" lol So I asked him again because he avoided the answer and he said he wasn't sure if they were going to do ecu flashes, he didn't think so. But he said again "It will be a complete kit, everything you need to make this car run flawlessly at the set boost which will be for 400hp to the crank" He said everything is ready and as soon as the CARB cert comes back it will be released. But if everything is ready, how can he not be sure if they're going the ecu reflash route? I'm starting to lose confidence in them. I also asked him if this "Complete kit" they are releasing will come with bigger injectors and he said no, it will be running the stock injectors.

My question to you guys is if I buy this kit for the 7k rumored price without injectors, and I wanted to up the boost, I would have to get bigger injectors right? My goal is to not go higher than 400whp. So I would be better off getting a kit like APS that comes with everything already? He also told me that the base kit will be released for the G35 then the Z, then the G sedan, and then later on down the road upgrades will be made so you can turn up the boost on their systems safely after you build the motor. So he said you will have to wait for their upgrades.
Looks like the JWT and APS kits for the G35coupe might be coming out the same month then. The hesitation I have with the APS is I don't want to replace my front bumper.

MIAPLAYA

iTrader: (3)

I read somewhere that it would include a piggyback controller. Actually I think it was in the latest SCC in the SEMA section

damen

The hesitation I have with the APS is I don't want to replace my front bumper. [/B][/QUOTE]

i'm not looking into changing my bumper either.

calimarc

i'm not looking into changing my bumper either. [/B][/QUOTE]

Because JWT utilizes two small intercoolers they save the front stock bumper in you guy's G?? APS is sticking with their same intercooler for the G TT kit as for the 350 I suppose? Have you guys asked Peter to consider alternatives? Might be a long shot but worth a try.

350z4steve

iTrader: (1)

Because JWT utilizes two small intercoolers they save the front stock bumper in you guy's G?? APS is sticking with their same intercooler for the G TT kit as for the 350 I suppose? Have you guys asked Peter to consider alternatives? Might be a long shot but worth a try. [/B][/QUOTE]

Why do you have to replace your front bumper? I think you have this confused with the Greddy Kit which requires removal of the bumper reinforcement. The APS keeps that intact no removal is needed.

damen

what we are talking about is how the Z's have the big open in the front of their bumper but, the G has two smaller opening on the sides of the front bumper.

peter already said that they have no intentions on keeping the stock front bumper with their intercooler. he claims that the stock G bumper won't provide enough air flow to the intercooler.

APS

I can understand your concern though APS engineers have serious concerns that the stock G35 front bar will supply sufficient air flow to cool 450 HP (approx 380 WHP) on 90 to 100 degree ambient day, very common in some parts of the US I'm told.

Thanks

Peter

APS

sorry.

Peter

More Power

Thanks for explaining. Just keep givin' it to us straight like that, doctor, I kin' TAKE it! (ha)

RIVET

I crack up listening to people here second guessing Jim Wolf on Nissan stuff. That guy has forgotten more about tuning Nissans than any 50 people on this forum know about it. Give it a rest.

G3po

iTrader: (8)

Peter ,you might want to clarify the front bumper and concerns with 450hp support. I assume you mean that air flow across the center mount FMIC is limited with the OEM G35 "facia" which only has side openings. With an inexpensive <$500 aftermarket facia , airflow should be as adequate as that of the Z kit.

With APS what needs to be replaced on the G35 is the simple plastic facia , not the bumper beam (as with Greddy). There are several choices for "open in center" facias. Stillen , Greddy , Top Secret to name a few.

The basic design compromise with the split "twin" FMIC design from JWT is that it provides greater boost drag (psi drop) than the APS "wide cross section" bottom to top boost flow area design.

damen

you may be able to get a new bumper for $500 but, it will be another $200-$400 to get it painted.

G3po

iTrader: (8)

True, personally I'm sinkin many beans into a built Long Block , Turbos etc. etc..so an extra couple $100 is noise. Now for those who intend to stay with the OEM LB and "out of the box" boost, the JWT system seems the best "stealth" fit for the G35. FYI I'm gonna use the Stillen facia with the APS FMIC, not as attractive as the Greddy or Top Secret, but it looks the most OEM-like and it's urethane much more durable than the others which are F-glass.

BrianLG35C

iTrader: (2)

Here's another option for ya ....

[IMG][/IMG]

G3po

iTrader: (8)

I like it looks alot better than the Stillen.
Subdued , not over the top.

Is it Urethane? were'd you get it?

APS

Air flow to the intercooler and the radiator are very limited with the stock G35 front bumper, I very much doubt that the intercooler/intercoolers or engine radiator will get sufficient air flow to sustain 400 WHP power in high ambient temperature.

Just the plastic fascia, will post pics over the next few weeks on the APS web site for you to browse.

Correct a split intercooler design will normally create a larger pressure drop across the entire intercooler system. A larger single bar and plate intercoler with a bigger opening in front bumper/fascia will provide a lower pressure drop whilst delivering the greatest reduction in charge air temperature.

Thanks

Peter