Downpipe And Crossoverpipe Advice

[BRAD_PADGETT]

I RECENTLY HAD MY STOCK 85 GN ENGINE REMANUFACTURED AND A LARGER CAM INSTALLED. I ALSO ADDED A COLD AIR KIT AS WELL AS THE ULTRACHIP FOR THE COMPUTER. I AM NOT A HIGHLY TECHNICAL PERSON BUT MY MECHANIC IS. I RECENLTY BOUGHT A SET OF POSTON HEADERS, NEW CATALYTIC CONVERTER AS WELL AS A HOOKER MUFFLER SYSTEM. THESE HAVE NOT BEEN INSTALLED YET. I WOULD LIKE TO GET THE CAR INTO THE HIGH 13'S OR LOW 14'S WHEN NEEDED BUT I WILL VERY SELDOM EVER GO TO THE DRAG STRIP. I ASLO BOUGHT AN ADJUSTABLE WASTE GATE ACTUATER. WILL THE NEW EQUIPMENT GET ME THERE? DO I NEDD A NEW DOWNPIPE OR CROSSOVERPIPE? HOW MUCH ADDES BOOST CAN I PUSH THE STOCK TURBO? ANY TIPS WOULD BE GREATLY APPRECIATED. THANKS- BRAD

 

[mike85gn]

Get a hotwire kit, an upgraded fuel pump, and an adjustable fuel pressure regulator. Be sure to get a scantool, and read the resources on gnttype.org for more information on tuning your car. You can pick up a downpipe and crossover pipe and that should help get you moving, low 14's and high 13's should not be out of the question.

 

[irockwithdirt]

What cam did U use?

 

[BRAD_PADGETT]

I do not know the size of camshaft that was installed when the motor was remanufactured by Jasper. The Jasper representative said that it would increase my horsepower from 200 to 225. He was right because the car is noticably stronger and the idle is alot different than before. I doubt that the camshaft is a very high performance one because the motor has a 3 year 75,000 mile warranty and is not classified as a stage one or two.
I am new to this and do not know what a hot wire kit is. I looked through my Poston catalog and noticed a fuel pump wiring upgrade which increase power to the fuel pump. Is this a hot wire kit? If so, the this kit along with a better fuel pump and adjustable fuel regulator surely would help. Will my stock fuel injectors still work? I still am not looking to go faster than high 13's
I am also researching whether I need to replace the crossover pipe and downpipe while replacing the exhaust heads and exhaust system.
Thanks- Brad

 

[racemybuick]

I have poston headers on my car and the stock up pipe, down pipe, and cross over. I am switching the up and down pipes to ATR up, and mease 3" downpipe for a low 12 sec quarter. With just an adj FPR, adj wastegate, oil pressure plate, the poston headers, K&N air filter, a posi locking rearend, and some racegas, my car ran 13.89@94 mph's a few months before I bought my car. Little did I know, the tranny was in seriously bad shape, and the motor was already on the way out, along with a leaky up pipe, and a turbo spitting oil. I figure the kid must have beat pretty hard on my car in the months just before I bought it, leaving me with all the work ahead. But point of the story is, with just a few simple upgrades in fuel, airflow, and chip, low 14's are basically a given. Depending on how fast you really want to go will then lead you on the path to upgrading, facilitating the need for a scantool, 3" exhaust, port work, roller timing sets, and so on and so fourth. If you want to go 14's, racegas and that adjustable wastegate can do it with nothing else. Your car would have to be in pretty good tune, but 14's are there. as for 13's, a better fuel pump, better regulator, and those poston headers will get you ther ein a jiffy. Good luck!

John

 

[BRAD_PADGETT]

Thanks for all the tips. One last question, what is a hot wire kit?
Thanks- Brad, 85 Gn in beautful shape!

 

[racemybuick]

this is what everybody is talking about: click me for hotwire info!
This link is an offer if ya got 200 bux, it is well worth it. If you need help installing it, then give is a shout, just make sure the gas tank is empty! lol...Good luck!

John

 

[1QUICK85]

Your stock injectors will still work with the new fuel pump, hot wire, and adj. regulator. If you are going to be replacing the headers............I would go ahead and throw on a nice down pipe too(you will need to move the ac condensor and passenger header out of the way), it will make a noticable difference. Get a nice up pipe to go with it too.

Not trying to start debates or anything...... But, --
Aren't the hooker mufflers bad for our cars compared to dynomax or some other brand...........I know this is highly debatable, some guys like 'em.
Here is another debatable one too.......
How much do Aftermarket Headers actually help our cars out, until you get really fast?

Even a good used 86/87 turbo would get you to the 13's and work with your stock injectors. The stock hairdryer will get you to the 13's, but it would be easier with the 86/87.

 

[Dwayne]

aftermarket headers....

The stock exhaust manifolds on the 84/85 TR's were the worst design that GM ever did. Using an aftermarket header on a hot-air car will be the biggest improvement you can make short of pulling the motor. Ask Lee Thompson, he'll tell you the same thing.

 

[1QUICK85]

So, how much of an improvement would you actually see on a car with my setup or my car..........with aftermarket headers over our stock headers(with no cracks....LOL). I thought that you would not see much of an improvement until you are going much faster?

But for a stock car wouldnt spending money on headers be a waste???~~ Bang for the buck............ATR headers are expensive and I know Poston's are cheaper but still.....couldnt you get a nice aftermarket turbo and injectors to beef up you ride better then headers?? The driver side header is the same as the 86/87's driver side header is it not?? I would think our stock stainless steel headers are better then those manifolds found on a 307 or 305 of that time period. Personally I think the weakest link in design of our hot air cars is the fact of no intercooler and the intake is very restrictive. Not trying to cause anyone grief or piss someone off..............just trying to see how much headers would compliment my car?

Later guys, Nick

 

[WH1]

The passenger side header is a huge bottle neck in the exhaust system. A set of LT or Poston's headers will flow way more than stock, kind of like a nice 3" Dp.