Throttle body modification
 

Hey guys. I am going to take my car to the track for the first time on labor day. My goal is to break 13.7 (my brothers heavily moded SC400) I have a JWT chip with 15PSI jets & a HKS cone filter. Everything else is stock. Any last minute mods I can do to free up even a fration of HP will be needed. The main thing I hope to do to gain power is cool things down and increase air flow. I was hoping you could shed some light on a mod I read about at a different site. http://searchwarp.com/swa14050.htm #5 talks about filing the throtle body (NA or TT) to allow the throtle to open farther. I haven't read about this minor mod anywhere else, and was wondering if it is worth tring. Also, do you have any ideas for temporary mods or removal of the grill or splash guard to get more are to the intake or any other cooling techniques? Thanks! :)

It's been discussed/debated on this site and the other Z sites. There is no proof this mod will give you any gain. I have seen no before and after dyno results to show an improvement.
I am on the side that suggests this mod is a waste of time. No proof is one reason but the argument that is strongest for me speaks to the alignment between the throttle opening and the actual flow of air through the intake.
If you look at your intake pipes you can see that air flow comes in at an angle and not completely horizontal. Based on that, it makes no sense (to me) to allow the throttle body open up more than it currently does (i.e. it aligns with the air flow).
To get the most air, the throttle should aligh with air flow. That is why that tab/screw is there.
Nissan engineers built a world class super car...they put a limit to the opening for a very good reason.

If you want to free up horse power you can look at lightweight underdrive pully, 1pc lightened driveshaft, flowing exhaust.
Temporarily and for the track, you could (if you haven't already) lighten the Z by removing spare tire, removing plastic trunk panels. Keep fuel level to 1/4 tank. Heck, remove the passenger seat if you want.
If you want more air through the bumper, go with a new bumper. Greddy is an example of a bumper with a big mouth.
You could also go with slicks for tires and start enhancing the suspension so what you have is efficiently going to the ground.

Thanks Dan! Are there any risks to doing this mod. I don't mind wasting an hour of my time, if I have nothing to loose and possible something to gain. Everything you said makes good sense, but at 15 psi a large throttle plate opening might produce less of a restriction = more power. Does any one have suggestion and maybe a link with more info?

That's the thing....there's no supporting documentation to prove that this mod is beneficial. As Dan said, the air comes up to the TB's at an angle, so having the butterfly at the same angle at W.O.T. will allow the most air into the intake manifold while minimizing turbulence.

The risk here is actually less horsepower.

The best thing you can do to beat your brother's time (which if you're a good driver, you should be able to....it might be close) is to ligten your vehicle and get slicks if you can. Lightening can be done by taking all unneccessary things out of your car before the race. Another trick that we've used at the track plenty of times has been to spray down the intercoolers with ice water right before the race (have someone at the line with a pesticide type spray bottle). Another thing that worked for a buddy (I haven't tried it) is he took out his sway bars. He said it allows the chassis to twist more and get more contact with the pavement. It actually shaved a 10th off his previous times....don't know if this was just a great launch or if the sway bar mod had something to do with it???

I read from other threads that about 15-16 psi is about the max boost I can acheive w/ JWT ecu and everything else stock. What size boost jets or in my case torch tips do I need to reach 16 PSI. Is there a conversion chart? Will .80mm torch tips give me about the max power on my set up?

You're right about your ecu. 15 is about the max. You have to install larger IC's and injectors if you want to run higher boost safely. You could also install an electronic boost controller. It's safer and provides for easier boost tuning.

For the mods that you have, you should really consider a quality cat-back exhaust system. You'll really notice a difference. When you decide to replace you clutch, you should install the lightened flywheel and 1-piece driveshaft along with downpipes and midpipes all at once....it's all duplicate labor.

Yeah, the downpipes have been ordered and are on the way. I am now tring to find a nice set of twin tipped mufflers. Something that looks stock but has a strait through design (like B&B only less $$). I'll have my friend who does custom exhaust mandrel bend some pipes from the downpipes back. Thank You! For the sarcastic member, your very helpful.

i think CC and 91 should trade titles.

You can change me to "The Retarded One" and then give 91 the "Z32 Guru" title. He's more deserving of it........ :) seriously. And then delete this post.

if 91 wants that title, i'll do it.

As far as you're concerned.......:Poof!:

Done!

Genie Rizz, i want a built SGP long block to replace my present one. I also want full suspension and brakes.....hey, it worked for CC.

haha....now thats funny, i dont care who you are, thats funny

Super Admin Rizz...can you get me straight As in my classes?

I was gonna go with the :rolleyes: or a :shakes his head:
but i thought i'd bust out a Riz classic for you two knuckleheads.



Um...no. :D

I kinda like sarcastic member that way people expect less out of me. With Z32 guru I feel that my answers would need to be right all the time and I couldn't be a smart-ass as much. That's just too much pressure.

Hi-tech redneck would fit better. It would leave people thinking,...is he just some dumb redneck asshole or does he know his stuff about Z's. I could be both and neither all at once. :D Rizz, or um...Genie...work your magic.

That was quick......Yee haw. :D

werent you making fun of rednecks a while back? :confused:

I make fun of everyone. What's your point? :confused: :D If you can't make fun of yourself, then you have a lack of confidence and no sense of humor, or at least that's what my therapist has been telling me. :D


j/k....head shrinkers are among the scum of the earth, but I do believe that crap about making fun of yourself. :D

It has been said that making fun of yourself itself can be a sign off insecurity. As in making fun of yourself before someone makes fun of one of your flaws would dilute what someone else says about you.
Damn those psychology courses in University f'ed me up more than they helped me.

Wow, this is way off topic.

Just like Eminem at the end of 8-mile.

Yes Dan, those Psychology courses f'ed you up.

What is Psychology?

I have no idea...but someone is making good money off of it!