I just swapped out my plenum for a plenum that has been ported (siemsed) and ported to match a 58mm BBK throttle body. I installed the 58mm throttle body. Ever since i did that, I have no breaks. The brake booster line that goes from rear of plenum to brake cylinder has very little suction. The fuel pressure regulator line that goes from FPR to plenum has no pressure. There is a line next to that on the plenum that has strong vacuum. On the bbk tb there are 3 vacuum lines. 2 main ones on the left - one only gets vacumm, the other doesnt. There is a small vacuum line that is under neath the throttle body and that has full vacumm. PLEASE HELP. I have re-torqued all the bolts on runners and plenum. I dont know why i am loosing vacuum pressure. The lines are not collapsing and there is just no vacuum in some of the lines.. does this sound like a bad port job???

 

I would check al of the lines themselves and make certain that there are no clogs or particles in the lines or fittings. There is no reason why you should have vacuum out of a line in the bottom of the plenum and not the back. Do you have breaks when you pump them? Or are they compleaty useless right now? If your engine is running you will be pulling vacuum. And I would not expect high 12s with that set up, maybe high 13s.

 

yeah io checked all the lines for clogs and leaks. Im going to get starter fluid today to locate the leak. I Have no brakes ata ll. They are solid as a rock. I do expect high 12's cuz i still have headers, ypipe, custom CAI, chip burning, and good tires. I expect most of that second to come off with the tires

 

Got your phone message Ken, Glad it worked out. Don't know where that junk came from, I hot tanked that plenum for an hour.-Mike

 

yeah mike no problem. Sorry for calling you on xmas but i figured you wanted to know. I thought it was a port job error cuz i did nothing wrong. I woke up this morning bugged about it and i said mmmm...what would happen if i blew into the line by my mouth.. and sure enough.. i couldnt. I looked at old TPI plenum that im sending to you and the thread that goes into plenum is just a thread and opens up in the rear of the plenum....so the only way it would be clogged was in that 1/2" tap./..stuck it with a clothes hanger and blew it out with compressor. tested it...bamb..... good to go. when i started...alot of black smoke... but i notice a HUGE difference with that 58mm and tpi plenum ported on stock runners. I am having really bad traction problems now. It just goes with very little throttle. AND EVERYONE ON HERE SAID 58mm TB WAS TO BIG................. your wrong. all of you. 58mm is the way to go..... thanks mike. plenum will be shipped out on monday

 

58mm isn't too big but it won't do anything for you.
Oh and how did that tornado work out? I got about 300hp from the 8 i installed [/sarcasim]
You are living on cloud 9 thinking you are gonna hit 12's. There is no way you are making more power than a new LS1.
Have you ran at the track before? You do understand that to pull a second off you need roughly 100hp right? Headers, CAI, and a chip will not do that. I saw 20-25 dyno proven hp with headers and a y-pipe, 30-35 with a cutout.
What you "noticed" was what you wanted to notice. you will not have gained any noticable power with a bigger throttle body and knocking down the egr walls.

 

Well its good you fixed your vaccum problem..
But I agree that the 58mm will do nothing on a rather stock TPI setup...remember TPI is about velocity...bigger is not always better..when you do the intake you need to mod it all at once to get the full effect..your only as good as your weakest link..aka your stock runners/stock filter setup is holding you back...great that your throttle body can move 1000cfm of air..pointless if stock filter setup only moves half that.
I don't agrree that you have to have another 100 hp to knock off a second on e.t.,since e.t. is based more on traction/weight/suspension...but I don't see a 12 second e.t. with your listed ,and future ,mods..

 

It should also be noted that some times a bigger throttle body can cause Acceleration enrichment problems. I have read and experienced that with the larger the throttle body, the more air is let in, duh. But that means that you would need much more AE in the lower RPM range and none in the upper.

There is a possibility that you could make it into the 12s, but that is very unlikly. If your tires are that good, you would break something after the first pass, axle, driveshaft, tranny, etc,. Look at what other people run, there are guys with a lot more money in there cars that can not or barly can do that. But you might go and prove us all wrong.....