Last weekend I decided to do the throttle body mod, but because of weather I didnt have a chance to drive it till tonight. I thought I would post what I thought about it for those who might not have done it.

Let me start by saying it was the first real mechanical mod I have done myself. I've done the TID mod and such but this was the first time I ever pulled the upper intake manifold myself. With some help over the phone from Chris Ng, and some cutting of that stupid *** 90 degree hose under the throttle body, it all came out OK.

I did what I'm sure is considered the standard throttle body mod. Removal of secondary throttle plates, thermowax, and high idle spring assembly. My idle had been wacky for a few months and I always assumed it was a bad thermowax, which is what prompted the mod in the first place. It went pretty smooth no major problems what so ever. I tapped and plugged the holes from the shaft of the secondary plates, cleaned everything back up and threw it back on the car. Since I re-routed that dam 90 degree hose and by passed the throttle body completely the installation was a snap.

I fired the car up, it idled really high about 2200rpm for a couple minutes then the idle dropped. The car almost stalled out but the ecu seemed to compensate and the idle increased to a rock steady 750. I tinkered with the idle mixture screw and the TPS and all was good.

So what did I think about it when I drove it? Off the line under normal driving it has a touch more hesitation, nothing major though. The real test came when I wacked the throttle in 3rd. Boost came up WAY faster than before. Almost instantanious. I laid into the throttle and blam right up to 12psi I really liked the change. It was like that in all gears, boost came on alot quicker for sure.

It was a cold night here about -10 degrees celcius. That and a combination of either wet or dusty roads ment I had no traction in 2nd gear. I would hold the revs at 3 grand then lay into it in 2nd and the tires would release right away. It was alot of fun.

Summing up I would reccomend this mod to anybody who feels they would like that little bit extra at higher rpm's, or have a high or "hunting" idle problem.

What do others think of this mod?

 

is this mod good for n/a's?



billy

 

i did the mod on my 88GTU, not too bad. you can just feel a little kick up top.

 

I agree. All I did was take out the Throtle Plates for the TB mod. No thermowax yet until I can find a 90 dagree hose. The car did have a little more pull after 6000 rpms.
I would imagine that with the more mods the bigger the difference will be. I just have bonez race pipe catback filter e-fan removed some emisions and luxuries. It was well worth it and u can do it in steps like i do. Plates first and was a sinch.

 

I've done the whole TB mod on my 90 GTU and definently recommend it. Its not going have as noticeable gains as on a Turbo model, but you will notice the throttle response quicker, and revving up to redline will take a little less time.

 

well then im gona have to do this one soon.


thanks
billy

 

If you are using the BAC valve you don't need to find any hoses. What I did was use the same hoses that were always there. I simply went to Lowe's and bought a barbed connector to put the two hoses together. The one from the BAC and the 90° one. Although, not sure if it will hold. Starting car sometime this week to find out.

James

 

i`ll give it try on my NA motor since before i`ll swap it for TII
i already did TB mod on TII TB, but haven`t installed it back to engine, don`t remember re-routing hoses, could u guys remind it to me ? pictures would be cool...

thanks

 

i did it, only noticed ii has a rougher idle when cold, but its worth the gains, and it cleans everything up real nice.

 

anyone got pictures of modified TB installed on NA ?

 

hIGGI - I did mine... it looks a lot cleaner and simpler... Working on my car is easier, and I guess it's weight reduction, too. Response may be better, and idle adjustment has been better since I did it. Starting in the cold was a little odd, but not bad. I'll try and take a couple pictures for you sometime.

 

cool! i would really appreciate it and other guys prolly too, good picture is worth of 3 pages how-to sometimes ;o)))
so take more pix and detailed ;o)

thanks

 

Eric, would u have have some pictures ??

I took my TB down yesterday, it was really dirty, rusted inside and lot of carbon...i cleaned it a bit but didn`t removed front plates yet, i need to know what to do with water hoses coming in and out ;o)

thanks

 

when i did the TB mod to all my n/a's i run the hose directly from the rear of the water pump to the back of the engine, i bypass the BAC valve's little coolant line and unscrewed it and threw it away, i lost like 2 oz. lolol, it feels good on an n/a, throttle response is definitely better, rev's quicker, and there is a noticeable increase of acceleration from 4500 up to redline and beyond, overall its a good mod, and if you direct that coolant hose directly to the rear of the engine under the manifold your intake temps probably cool down a good 20 or more degrees i would think, good luck

 

i would love to see some pics ot a site refrence i was thinking about doing this today if i can get some good information... thanks

 

the whole right up is on fc3s-pro.com just be sure to remember where all the lines go when taking it off i'm having that problem right now and it sucks!

james

 

thats too bad... maybe you guys should label the lines with masking tape before taking them off!!

 

don't remind me!

 

I have done the TB mod on my '91 turbo and it starts up and idles at 750rpm. Sometimes want to die but it normally dosn't. That was with a 40° F start last night.

Still breaking the engine in so I can drop the hammer

Just wondering if any of guys stuck your TB infront of a bright light. Did you see much light around the throttle plates? I am having only 11" of HG at idle. Wondering if a gap is a reason?

James

 

still noone with pictures ? :o)

 

http://fc3s-pro.com/TECH/HOWTO/TBM/tbm.html

 

those pictures are from TII TB and does not show TB installed and hoses rerouted..

 

when you take out the gold plates in the throttel body take a grinding bit (metal bit not stone) and port out all that extra **** (pardon my lang) that was seperating the flaps. You dont need it anymore, and it will give you even better air flow. I did this on my Turbo SE and it worked 50% better then the "just take the plates out". So in addition to the mod, if you are daring enough, port that sucker out.

 

If you would just go out and do it, its blatantly obvious what to do.

 

I started my car and it was running for about 30 seconds. And I wanted to get out of the car to do something. It wanted to die because it was cold. So I clicked on the AC. The BAC held my idle up for me So if you have a BAC that could help you with cold engine drivability issues.

James