Down Pipe Advice?

[Rgr Pete]

After 8 months of work on the car, I'm getting ready to fire up the GN. I need a down pipe but with all the different choices any advice would be helpful. The motor is stock with a TA49 with 60lb. injectors/TT Chip.
3' or 3 1/2? External BOV?

 

[MY T FAST]

i bought a 3.5" but only bc i found it hella cheap. 3" dps have been into the 9's, so most agree that is plenty. internal/external gated will bring a huge debate, mine's internal with no issues. rjc, TA, gbody, all make good pipes. pretty much whatever you wanna do.

many say a dp isn't needed until youre in the 11's but i think it looks real cool and it cant hurt anything.

 

[Slow91z]

3"

Internal is all you need.

 

[Boost231]

go external gate if you can. internal will work but i really like the external now that i switched.

 

[R.I.P.92Rolla]

i bought an rjc 3inch internal....jason does some quality work, highly reccomend it if you go internal wastegate.

 

[we4Mateo]

i bought an rjc 3inch internal....jason does some quality work, highly reccomend it if you go internal wastegate.

x2...last dp you'll ever need.

 

[psycho6cyl]

go external gate if you can. internal will work but i really like the external now that i switched.

What changes did you noticr and was that the only thing you changed whn you noticed the difference?

 

[Slow91z]

What changes did you notice and was that the only thing you changed whn you noticed the difference?

The main difference people notice when they switch to a ext. gate is real steady boost...With a int. gate the boost has a tendency to fluctuate slightly throughout a run.

 

[wmerrell]

My GN is equiped with an internal 3" downpipe, TA49, 42.5 lbs injectors. How much gain in horsepower would a switch to an external waste gate 3.5" downpipe produce?

 

[Slow91z]

Just about 0

 

[we4Mateo]

Just about 0

x2.

 

[Boost231]

with the external gate i now have rock steady boost. I picked up alot of power switching to a external gate for a few reasons.

one the turbo spooled much faster with the external gate
two the boost pressure was rock solid
three no more boost creep
four i had whatever boost i set it at from lauch till the end of the track this is what helped me the most. with the internal gate i would be at 20psi down the track and then at the top in the boost would creep to 25. now i can set it at 20 and its 20 from start to finish or 25 start to finish. this helped my E.t's alot since i could keep my boost solid at a set #

 

[Rgr Pete]

Boost,

Sounds like external is more precise. Which downpipe and BOV did you get? A three inch DP? The current engine is a stock replacement so I can build up/stroke the original blown up engine, just don't want to have to buy a better one later.

 

[bison]

Id run the stock downpipe and look elsewhere to spend your $. A dp isnt worth much at your level unless you plan on leaning on it really hard. Less than 10 hp if your already making 400hp.

 

[Bigjack7440]

I took off my RJC SSDP witch was a great DP , but I had some boost creep with the new 6262BB even with Cal from Hartline doing the porting on the exh side . Now with that said he used a RJC DP with Jasons new 1.78 puck and it was solid . I always wanted a ATR SS DP and I got a realy nice deal on one and it made my boost rock solid , and no more turning a rod to raise and lower boost. I could have got a boost controler but I never did. If you want a nice DP I would TRY and find a ATR or order a RJC with the new big puck and get a realy nice boost controler. If you go bigger on your turbo it will help but like bison said ( free advice ) lol it want help alot but when you go to a bigger setup it's money well spent. By the way this is my 3rd and last DP .

 

[TurboTnZ06]

External gate is the best. Find a used ATR and upgrade the gate on it. I have one- rock steady boost. Just put a RJC on my T to try it out for the stock appearing look and sure enough, I'm messing around with controlling the boost again like the old days. On my GN I have a stock elbow with a Kirban 2 piece 3" pipe that fits on the stock elbow. This is the most economical upgrade, but be prepared to take it on and off a few times to fit it. Also need to use the exhaust sealer stuff so it doesn't leak.

 

[Slow91z]

My external gate is nice....BUT I bought the car that way and it's not SO nice that I would have spent the money, my old car with the int. was fine.

I mean geez there are TSM car's out there in the mid 9's still with the int. gate.

 

[Razor]

Stock down pipe is fine for a motor running stock boost levels. Even elevated boost levels. I'm with Bison on this.

Putting a 3 or 3.5 inch downpipe on a stock motor is a waste of time and money.

Once the wants/desires of running 24+ PSI come to play.. then its a different ball game.

Unless its done for looks then put the 5 inch one on

 

[Slow91z]

I put a 3" on my last car when it was stock and I really liked it...The spool up difference was what sold me.

 

[Razor]

Its a well known fact you cant put a stock downpipe car into the upper 11's.

Rgr Pete never stated performance goals. Except injectors changed, chip changed and one step above stock turbo size. So if the car is kept at pump gas 16 PSI levels.. there should be no diff in performance.

If stock DP is rotted, missing, destroyed, etc... then a 3 inch DP integral would be my choice.