2 questions... please help

[ZX2000]

i have a '90 plymouth laser turbo in my posession and i took the throttle body off to bore it out and am wondering what a couple things are.

#1. the sensor in the throttle body housing?

#2. the spring w/ the spanner nut attached?

anyone who can help please. i literally just got it and well, it's not mine. it's my friends brother's and he said "hey, do whatever you want to it. i don't drive it and doubt i will for a long time. it needs to be driven and it would be a waste to let it sit in my driveway." so him and i are building a racecar out of it and doing all the stage 1 and some of the stage 2 stuff on. im a machinist so im doin all the headwork and making the tb bigger and also gonna port the intake manifold. also, anyone know how big i can port the tb? it's 60mm right now i know, how much can i take off? thanks in advance.

[WildJokers]

There should be 2 sensors on the TB. There should be the TPS ( throttle position sensor, directly connected to butterfly ) and the Ide control motor. Idle Control Motor is on the lower left side of the TB.

[ZX2000]

cool, thanks for the quick response. i guess my friend took the tps off before he brought me the tb. the other thing was the spring w/ the spanner nut? i dunno if you know anything about it. i took the smaller plate off (held in by phillips head screws) and the spanner nut is right there. 2 little holes in a plate lookin thing. i dunno what it's for. thanks again.

[kjewer1]

The 90 TBs are a little odd. I hate them. A 91-94 would be easier for me to help you with. The important parts are TPS on the front side, throttle closed switch (single wire connection) on the firewall side, and FAIV/ISC hanging of the bottom. The screw on the front side is the BISS (base idle speed screw).

60mm is plenty big, trying to enlarge it requires extreme precision (CNC tooling) and a plate that will seal in the new bore. COnsidering that poeple run 9s and 10s on 1G tbs, I would focus my efforts elsewhere. But giving it a good cleaning and replacing the shaft seals is always a good idea. www.vfaq.com should have a vfaq for changing those seals. MachV is usually the best place to get them, no searching and no hassle, even if they are a few bucks extra (11 bucks as opposed to 7, who cares). Good luck.

Edit> just realized you said you are a machinist. So I'm sure you have the equipment to pull it off. However, I would still recomend against it, there just isnt any power to be gained there until you are somewhere over 600 whp. And poeple do more than that on the stock TB. Time and effort better spent on something that would provide some more usuable gains.

[WildJokers]

If i'm gathering what your saying is correct, that would be the throttle assemble. There is only 2 places that have springs on the TB, the biss screw and the Throttle assemble. Correct me if im wrong on this assumption, since i had to go look out on my 6bolt to make sure.

[1stGenRocks]

the biss doesnt have a spring, its just a plastic screw

[fussman238]

good luck on ur racecar guys!

[ZX2000]

i've done this to a # of tb's off turbo cars and it always helps. never run into an exception. im porting the manifold too and we're doing headwork and portmatching. the more precision it is the better off we'll be and when we upgrade the turbo the more boost we can run. plus we're on a budget. im porting it to 64mm and making a new butterfly too. should be sweet. ill post pics of it when i get done, and also, i doubt ill notice it cuz it's gonna be a whole new car by the time we put it all back together to drive... but im sure it'll help.

that spring isn't the throttle assmebly. it goes straight through from the back. there is no opening for it on the front of the tb but if you take the little plate off the back of it (3 phillips head screws holding it in) there is a spanner nut (2 little drilled holes 180* from each other) there that holds it in. i can't turn it w/ the spanner wrench i made for it. i even made a fitting for an impact gun and it don't work. i tried heating it up (might be locktited w/ some strong shit) to loosen it and got it an 1/8th of a turn but thats it. damn thing won't come off. i know it can though. anyways, it's almost completely concealed but if you look in the tb from the topside down the hole for the idler control motor it's right there between the throttle bore and the coolant fittings. i dunno what to call it. hopin you guys can help me.