Hi Guys, I have a 2003 350Z Auto Transmission and have just recently installed GTM TT kit and transmission valve body upgrade. On the dyno I'm getting 226kW which is about 303hp. Does this sound right? I thought it sounded a bit low. I realise manual transmission would get more, but still. Thoughts?

Note that I have not done any other mods as of yet.

STAGE 1 (TURN KEY) TWIN TURBO KIT
http://www.gtmotorsports.com/product...cat=258&page=1

TRANSGO VALVEBODY UPGRADE KIT
http://www.gtmotorsports.com/product...cat=262&page=1

 

seems quite low

 

Sounds low but many things could be the cause of that. At what boost are you running? Other supporting mods? Also, what dyno are you on?

 

whateva the stock boost of the kit is, not sure exactly, maybe 6psi?
no other mods at present, waiting for exhaust from fast intentions though.
see dyno chart below:

 

If you're still running stock everything other than the mods you posted (TT and valvebody upgrade- which contributes nothing to the result) then I'd say it's about right. You'll have a constipated exhaust that isn't contributing anything to the generation of power, a generic "custom mapped plug-in and play engine management" EMS... At 6 psi.

Good baseline though- once you get that new exhaust in there (Test Pipes included I hope) then that will give the turbos the opportunity they need to benefit from the exhaust gas.

 

Should be at least +50 more hp IMO get some tuning done

 

The dyno numbers look about right for the stock exhaust, 6psi of boost and 90 degree day on that type of dyno.

The stock exhaust is holding back anywhere from 50 - 80whp.

If that still isn't enough power for you, then a boost controller will help you get more. Just don't go crazy with it. Keep it at or under 8 - 9psi.

 

This.

If you wonder why go peruse my "build thread" and skip to page 14. 1-13 was all the fluffy, happy build stuff. 14-38 or so was reality.

Good luck!

 

ah didn't realize stock exhaust + cats... not gonna make much more than this

 

thanks for the feedback guys, I wasn't getting upset or anything, was just checking if it was right or not. If it's not right then I would go back to performance shop to make it right hehe.

I have already on order a fast intentions exhaust with a custom straight through x-pipe (replacing a muffler). And now I'm considering high flow cats as I would probably get done for test pipes. I spoke to fast intentions and they recommended me they're 100 cell HFC as anything less (eg more than 100 cell count) will not handle heat from FI setup:

http://www.fastintentions.com/produc...roducts_id=136

The product in link is for 370Z but they also make for 350Z.

What are your thoughts on this guys?

this is the exhaust:



This replaces middle muffler:

 

I would def go for test pipes. Not sure if u can get away with them but any restriction is a bad restriction, eh?

I have a 2.5 fast intentention setup and love it. Although I do have external
Waste gates. I would have gone with motordyne if I was doing it now.

What u doing bout intake? Even a cheap spacer should help and do it befor tune.

 

I use the vibrant 3" mettalic cats and 3" downpipes for the past 3 years. Based on my power numbers and feedback from my tuner they are not causing any noticable flow issues... maybe 10whp at best. I don't think 2.5" cats of any type are going to hold up well with F/I and not cause restrictions, especially if you're running internal wastegates. Whatever you do avoid ceramic cats.

 

THESE were recommended toe by the folks in the know when I was concerned about the odours from test pipes. I was making the transition from HFCs when I made the move to FI and most recommended getting away from HFCs of any sort because they were essentially a "consumable" item when dealing with turbos / SCs.

Definitely worth a shot. RCDash said they reduced restriction from about 50-70whp down to about 20whp. I'm still thinking about them... Not bolt on but most shops could make it happen.

 

Are test pipes legal? Test pipes are a straight through pipe that have no cat converter right?

 

Anything except bone stock cats are illegal in most places. At least in some states in the USA, turbo alone is far more illegal than anything else... don't waste money trying to stay legal if it's a lost cause.

 

Visual inspection for cats will get the job done most anywhere. Technically, replacing stock cats is illegal unless they fail and need to be replaced but of course, you could always say they failed. I doubt anyone will give you a hard time with aftermarket cats, especially if you get a heat shield on there.

 

Ok finally got the exhaust on (stock cats) and went on the dyno:

My concern is that bump I have circled. The shop said this is the converter kicking in, I wasn't sure what he meant by that but something to do with the auto transmission.. thoughts?

 

Also I never realised how much a difference an exhaust can make :O

 

For a turbo setup it can be huge. You want as little back pressure as possible after the turbo (which is kind of opposite of SC and many NA setups).

As for the loop in the chart, yes that is normal to happen but it seems to be happening a bit late... they may need to adjust the calculated load so it locks up sooner on pulls. If it is locking too late, you can end up overheating/destroying the auto tranny.

 

spoke to the shop again and said that driving on a road vs. dyno is different and the loop would happen earlier if on road. He explained it in more detail to me but it was all jibberish to me lol.