I have done the following mods and was looking for any suggestions for more power other than F/I. I have an early 03 AT Sedan.

- UR pulley set
- Injen intake
- Crawford V5 plenum
- JWT cams
- DC headers
- Crawford cats
- Borla exhaust
- Grounding Gear kit

I have not done anything to ECU yet, want to finish mods. I do not want to do anything further to internals. Any and all suggestions are greatly appreciated, even if it is replacing something I have already had done.

Thanks.

 

Would a port and polish give you any gains? You might want to look into that.

I would also try doing some research on my350z.com. Some one was telling me about a N/A 350z that is so fast, it spanks Z's that have FI...I don't know if it's true or not, but I'd check it out.

 

with all those air flow mods, have you checked out your AFR lately? i know you said you wanna wait on the ECU but if you went with the UTEC for example you could easily retune for changes to mods later, and it might actually give you some good gains if you're running lean. (which you probably are)

(with my headers, cats, full exhaust, intake, and plenum spacer my car only put down like 231 on the dyno, but my air fuel was lean. i'm hoping that tuning it with a UTEC will bring out the power that it should be making with a proper AFR.)

aside from that, maybe a larger throttle body combined with a new crawford cast plenum? (which i thought had a larger opening at the top to accomodate a larger throttle body?) perhaps Crawford headers, which are supposedly the best (although install on those is gonna be a pain in the ***) and maybe an exhaust that flows better than the borla? (i don't know much about sedan exhausts sorry)

you could also make improvements to the 5AT, like a valve body upgrade, higher stall torque converter, maybe a 3.5 differential from a 6MT... those don't increase power but would certainly make better use of the power you have for quicker acceleration

[offtopic] how do you like the JWT cams? did you really feel an improvement when they were installed? and how is their "driveability"... it still idles fine and is ok at partial throttle/low rpms, etc? [/offtopic]

 

Hey I appreciate the help. I know I may be running lean, but the last thing I do will be re-flash ECU. Already have the Crawford cast plenum. DC header install cost a lot and may not be worth switching to Crawford for 2-3 more HP. The Borla system on the sedan is a true dual system like Stillen. Most of the other systems are Y-pipe single exit. I would think a true dual would flow better that single unless someone knows differently. I have thought about valve body upgrade, but worried about possible damage removing, shipping and re-installing. Good idea about gear change for acceleration, don't need the top end for my style of driving.

JWT cams are great. Noticed biggest butt dyno gains with this mod. Everything went well for my car since it is an early production 03, 07/02, which these cams were designed for. Works with stock springs, idles just like stock, no problems. I do not believe these cams work with newer 03.5 and up. I have the mechanical fan on my car.

 

1) 3.53 gears out of a 6MT
2) Crawford Throttle Body
3) The UTEC seems like a good option, but there’s limited shops that know how to tune it.
4) The mechanical fan, if it’s driven by the motor. Replace it with an electric fan.
5) Adding an X-pipe to your Borla should boost your midrange torque. I’m adding one to my Invidia G200 and will post the dyno .
6) Light Weight Wheels
7) Light Weight Drive shaft
8) Modified lower 287 plenum

 

actually the UTEC should be fairly simple for any tuner to figure out since you can input actual degrees of timing as opposed to offsets from the ECU's timing... the UTEC fires the coils using the timing you specify (ie "15 degrees" instead of "stock timing + 10 degrees", etc) this should take alot of guesswork and danger out of tuning since the stock ECU is unpredictable. the only beef that people have is that it's a text interface using HyperTerminal instead of a table based GUI

i don't mean to sound like a UTEC groupie, but i've been doing alot of research on it, so i figured i'd share

 

also the UTEC is not the same as an ECU "reflash". I agree with the others that it seems a good option.

A few others have reported great success with the 3.9 final drive gear ratio and torque converter upgrade (supposedly more performance gain than all other mods combined). do a search for posts by "ismsolutions".

 

searched, but apparently no one reviewed this yet. do you have any comments about this item? crawford bores out the throttle body to 73mm. what is it stock? - does anyone know?

 

SI_G35Coupe,
I miss read a post by MRC about the UTEC. If it is that simple to use, I may buy one next year (tax return).

Codeflux,
There was a post on My350z , some one talking to Doug (dougrace zs) about the bored TB. I couldn’t find the post. Basically it didn’t make a difference unless you had cams and head work.
http://www.crawfordz.com/TB.htm

 

With all these mods, im sure youre not worried about MPG.
Get yourself a set of 3.97 Final Drive gears. You'll drop atleast .3-.5 a second off your 1/4 mile. You'll lose like 10MPH off your top speed, about 1-3 mpg off your gas mileage, and youll lose your cruise control. Other than that, your car will pull like a bat out of hell after the gears. Its really worth it if you really want speed. It also put a nice lil' dent of about 900 (for just the gears, then you gotta pay for installation) in your pocket. Its been proven, NA mods dont do much for the VQ. You either go FI or get about 20-25 RWHP with all this money your spending on NA mods. Your call.

 

is it me, or is that in the totally not worth it category?! especially the cruise control part?!?!?!

 

Thank you for all of the ideas. I think the throttle body sounds good as I have the cams and Doug @ Crawford said to expect another 4-5 HP. I plan on doing the gears in the future along with LSD. The electric fan sounds like a good mod. Does anyone have a system to recommend?

 

3.91 EVO gears, TQ Converter, and valve body in the trans...you'll see great 1/4 times...

My mods:
05 Coupe/Auto/Ivory Pearl/SportTuned SuspensionPkg-Aero Kit/OEM 19's - Chromed/Stillen CAI/UR UDP/Borla Exhaust/3.92 Gears/Nismo Cams/Performance Heads/Trans Kit and 3600 Stall Converter/Motordyne 1/2" Spacer with ISO Thermal/JDM Clear Corners/K40 Radar Protection/Hyper White's everywhere possible...more

 

ISMsolutions,

Who did your headwork? are you using stock heads or the NISMO heads? IF NISMO heads, are they a different casting than the stock heads?

Thanks,

Andrew

 

[QUOTE=ISMSOLUTIONS]3.91 EVO gears, TQ Converter, and valve body in the trans...you'll see great 1/4 times...

Can you recommend a TQ converter?