Please help me, Downpipe question

M

MyBoosta

More Boost = More Love!
Joined
Nov 26, 2006
Hello fellow boosters,

I am in the process of making a quick decision and I need some help. I has been hard to find a decently priced DP new or used. However, I just noticed that Poston Enterprises sells their own in-house 3" DP's that is a two piece that comes complete with clamps.

My questions are: have any of you tried this unit? And will this work on a stock turbo GN with a test pipe and dual pitbull exhaust system? Will I see any performance gains on my basically stock GN with stock turbo/ Dutt neck IC with a 93oct TT chip set up for 17 to 18 psi?

Please don't laugh, I am new at this!

Thanks in advance for all your help:smile:
 
I just went with GN1 (GN1performance.com) downpipe. I went external WG but they also have internal WG models. I did the SS with muffler flange and dump with header (three bolt) connection. I will be taking off a BGC and 3 inch SS set up, and what you should see is faster spool up, less back pressure. If you want my old unit it will be cheap, I have enough junk in the garage already.:D
 
1991syclone said:
I just went with GN1 (GN1performance.com) downpipe. I went external WG but they also have internal WG models. I did the SS with muffler flange and dump with header (three bolt) connection. I will be taking off a BGC and 3 inch SS set up, and what you should see is faster spool up, less back pressure. If you want my old unit it will be cheap, I have enough junk in the garage already.:D
Click to expand...

Cool, talk to me.

I take it BGC means Bowling Green Customs right? Do you have any pictures whatsoever? Is it in good condition? Meaning, not a pile of rust that will last me one year?

Thanks for looking out brotha!

Oh yeah, will it work with what I have?:smile:
 
Check with Gbodyparts.com, Fullthrottle, Cottons and a few others on here. Their design is a proven winner. I personally do NOT like the Poston down pipe in that you keep the very restrictive stock elbow.
 
turbofabricator said:
Check with Gbodyparts.com, Fullthrottle, Cottons and a few others on here. Their design is a proven winner. I personally do NOT like the Poston down pipe in that you keep the very restrictive stock elbow.
Click to expand...

Thanks Mr. Fabricator

I just spoke to some of those guys, and one told me that a DP wont do anything for my car (a practically stock GN), while another one said that it helps. However, a set of headers would be better.

So from your personal experience, which is best bang for the buck? Does a "downpipe" help stock GN's like mine with stock headers, 2 1/2 test pipe and ATR dual pitbull exhaust system? Or would headers net the bigger gains? Crap, it seem that I'm back to square one.

My car feels like a low 14sec car or maybe high 13...who knows. Would a DP on my application help me get her down to the low 13's? Or are headers (more expensive add on) would be the ticket?

So many combos to choose from, which one is the most effective for a street set up car that runs 99% of the time on the streets. I may visit the track with this car once or twice a year and that's it! I just want her to have some more punch for those times when a G35 sedan or even a Cobalt SS pulls next to me:eek:

Thanks:biggrin:
 
In your case, the best bang for the buck would be an alky system and crank up the boost to 25# or so.
 
Who ever is telling you headers are the key is dead wrong. Guys run well into the low 11's and I think high 10's on stock headers. Your better off with a gbodyparts 3" downpipe.

But even before you do that, have you addresses your fuel system? A upgraded fuel pump, hot wire kit and an adjustable fuel pressure regulator is a must. Maybe even bigger injectors. Also a scanmaster from Full Thottle to monitor what the car is doing is big, real big. Your chip and a exhaust are a good but these things I mentioned need to be considered too.
 
high 10s :) , think again jason , guys run 9s on stock , nothing but stock headers on my 86 ,
 
I can't believe some one told you headers first. Must be a pile on some ones shelf.:eek: I think it was already said get your fuel system where it needs to be first then get a scan tool.
 
A better downpipe is an important part of the chain of improvements to your car however the advice from purple 87 is the approach you should be considering first. Fuel pump, FP regulator, valve springs, timing chain, air filter, even the spring cleaning recipe, should all be addressed before a downpipe if they haven't already. You also need a monitoring device like scanmaster so you can make adjustments and avoid knock. Do you have an adjustable waste gate rod or boost controller? Someday you'll need a downpipe improvement and it won't hurt anything to have one now, just don't forget the important groundwork if it hasn't been done already.
 
Yeah, it sounds like the headers/downpipe prioritizing is backwards.

I wouldn't worry about headers unless I was nipping on the 9-sec door.

I noticed a seat of the pants difference when I went to a good Terry Houston style 3" downpipe.

The factory style 3" pipes that use the factory elbow are a pain in the a$$ and the inside allen bolt is a mutherfukker to get/keep tight.
 
ever see a idot with a honda put a big 3 inch pipe to the back of stock car \
and it slows him down you need some back pressure
 
Wow guys, thanks.

Allow me to address to some of your questions. My fuel systems consist of the following: Walboro 340 w/hot wire kit, 50lbs inj and FP regulator set to 43psi idle vac off as per TT chip instructions.

This is what was on the car when I purchased it: dual ATR exhaust/ test pipe/ stock turbo with adjustable rod/ stock DP/ homemade CAI...I added)/ the above mentioned fuel system/ 3" SS Impala MAF/ Translator plus/ Extender chip (currently being changed to a TT chip...I added)/ 200/208 cam(sounds stock)/ D5 loosen to about 2,600rpm/ fully built 200R4 with big Servo/ Dutt neck on stock IC/ rear air bags and cross drilled brake rotors. The car has about 26,7XX original miles. It's a hard top and EVERYTHING WORKS, and I mean everything!

The car is currently in the process of being super tune (all sensors being checked and re-set to specs and so on) by a Buick tech that has all the scan-tools necessary to make adjustments. He asked me to get a DP NOW if I wanted to so he can tune it all at once. My car has been sitting in the garage all winter and now it's time to get her back on the road. All the little things like plugs, plug wires, fuel filter, oil and oil filter were freshly added by me.

Once the car is finally tuned, do I still need to have this scann thingy?
All I wanted was a nice high 12sec car but it seems that in order to do so with a GN, I need to have Racing fuel, Big Slicks and Boost levels in the low 20's to get there...correct?
Heck, my old automatic 2001 LS1 Formula only needed a cold air kit, a few small PCM adjustment and DR's and that bad boy ran 12.90's all day long! And it ran low to mid 13's on GY GS-C's in the summer! CAN GN'S DO THE SAME? Or do I need to do what I mentioned above on this parargraph? I mean, is technology for the LS1 that much greater?

Thanks
 
race gas and 20-22# and proper tune and youll be doing 12lows on a stock turbo , big diff from 12.9s

i ran 12.4 on goodyear eagle gs tires

your mech only needs one tool to check /set sensors , a freaking scanmaster

you could do it yourself and you should learn to do so as no one can keep an eye on its tune as well as tthe guy who drives it every day , and yes you will need a scantool to stay ontop of the tune even if your mechanic "set it up"

get a scanmaster and go to gnttype.org , vortexbuicks-etc.com and read , read , read

Vortex Turbo Buick Performance

Turbo Regal Web Site
 
headers?

headers are great for power on a small block or big block engine, but like the guys said above not needed right away for a turbo engine. there's alot of guys out there running really fast times with the stockers, just make sure you have no cracks in them and you should be fine. I just bought a set of poston headers but will hold off on putting them on until I rebuild my engine and really need them. Go with a dp. there's alot of vendors selling really nice pieces on the board or check the parts section you might be suprised at what you find, just make sure the rest of your exhaust system is up to the task of getting rid of the gasses I'd recommend a hooker 2 1/2 system at the least if you haven't upgraded the system already. good luck
 
Okay guys, bottom line:

Is a DOWNPIPE a welcome addition to a practically STOCK Grand National?
(please see my mods on the above reply)

I would hate to spend $200 to $350 or more for 5 or 7 additional horsepower!

Thank you
 
the pipe will offer a gain ,and looking at your combo its up there on next step list
how much will it help at stock i cant say , but it will allow for future upgrades to reach more of their potential
but it is a sizeable output that right now might be better spent on a scanmaster , get all the systems of the car operational and be sure they are ok on a daily basis , work on educating yourself, getting all the systems of the car working flawless ( safety first , brakes, fuel ignition) and learning to tune while the car is at a lower hp level , less chance of catastrophy due to an error,
when you're tuning wont get you any further gains then look at parts, you should be low 12s by then

alky would be a better gain and can help in the learning stages due to some added protection from kr , youll always know with 93 youll have enough octane to not have knock and you can dial in a little more when conditions change
 
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