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86Nick
11-07-2005, 08:59 PM
On A Pretty Much Stock Car Is It Worth The Money To Put On A 3" Down Pipe.

Keller
11-07-2005, 11:04 PM
This is my opinion only. Others will likely disagree.

Larger downpipes don't really shine until you have a car that can use it. That means a car with a larger turbo, and tuned to go high to mid 11s. Likely moving a lot of air, and likely at higher than stock boost levels. I think they aren't worth it on stock to mild recipe cars. Those combos just can't make use the the improved flow enough to make it shine.

We just had a car from our local club on the dyno this weekend that was running a stock turbo. First with a Terry Houston pipe, next with a stock pipe and elbow. After adjusting boost and fuel for each combo, no real gain in power was seen with the THDP. With just the raw swap from the THDP back to stock, he was down on power. But by tuning it back to use the boost/fuel best, it was back in the same place.

FWIW, it was a borrowed THDP and it was coming off the car anyway.

In my opinion, its not a first step modification. Part of a larger level modifcation process that requires some thought, planning, and tuning.

GNXDad
12-04-2005, 12:57 PM
I agree. Unless your car is highly modded and moving alot more air through it.

Keller
12-04-2005, 01:45 PM
Just to follow up...

After reviewing the data, the individual in question did find that the power came on a wee bit earlier with the THDP than with the stock downpipe/elbow. So he believes it was allowing the turbo to spool faster and/or earlier. No argument here.

So there may be some advantage to the THDP, even with a relatively stock combo. i.e. Minor spool-up advantage. And I do mean minor - this was a dyno pull, after all. However, it appears to not result in more power/torque if tuned effectively at pump gas boost levels with a stock turbo, for instance.

I still think there are better first places to spend your money.

buddiiee
12-06-2005, 08:45 AM
They do help, but like they said, not in your car... it does help spool up a little, as i know someone that did that exact swap, and it did help him a little but, honestly, that should be the last thing youre worried about right now. after youve done the spring cleaning, get a scan master and tune the car. if its still not fast enough for you, do the little things. first is the fuel delivery. next, do valve springs. then maybe a tin man cold air intake, maybe a nice exhaust system. swap out a chip or two. turn up the boost a little. thats all ya really need. theyre simple, cheap, and reversible, should you want to retain the collector car status. Theres a guy here in michigan, a president of a local club, pullin low 11's with the least amount of mods I have ever seen in my life. I thought it was impossible.. its not. its all in the tune, boost, and how well your tires grip :flamer:

NOTACARLO
12-08-2005, 10:28 PM
You could always compromise and get RJC's 5 INCH DOWNPIPE. :D