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I spoke to a Doctor Gas about an X pipe

10K views 55 replies 18 participants last post by  04titanss 
#1 ·
I called up Doctor Gas and the bottom line is that I need an Xpipe to achieve maximum performance and to smooth out as well as quiet the exhaust note.

I asked a ton of questions and here is the briefing.

Q: Is a 2.25 pipe big enough for our trucks to achieve maximum performance between 350 and 400 HP.

A: No. 2.5" would do better performance wise but it's a truck so you may want more torque for towing.

Q: what's more effective, an H or an X pipe.

A: An X pipe.

Q: would there be any advantage to using both an H and an X pipe.

A: No. The H pipe would disrupt the flow prior to the X pipe and make the X pipe less effective.

Q: I spoke with Magnaflow and they said their X pipes were the kind used on NASCAR, is this correct?

A: He just laughed at first and then said No, their X pipes are not used on any NASCARS that he knows of.


I actually asked the guy at Magnaflow to clarify for me and he said that what he meant to say was that NASCARS use X pipes and Manaflow sells X pipes, lol.

The man at Dr Gas told me that's correct, NASCAR uses Dr Gas X pipes at the Super Speedways.


Q: What makes your X pipes different from Magnaflows.

A: Dr Gas X pipes achieve a true merging of the gases from both sides of the motor via tight radius turns whereas the Magnaflow is simply a chamber they dump the two sides into and it is not as effective as the Dr Gas design.

Q. Where should I put the X pipe?

A: As close to the mid pipes in your truck as possible.

Q: What type of power gain can I expect to see from my engine that dynoed at 343 HP?

A: About 5HP and 10 FT LBS of TQ, minimum.

Q. How much is your custom 2.25" Tandem X pipe and what is the lead time.

A: it's 184.00 and the lead time is about a week.

Q: What dimensions do you need to make my custom X pipe.

A: Your pipe diameter and the center to center distance between them.

My truck should sound about like this with the X pipe on it.

http://www.youtube.com/watch?v=W-NbX7s5k_E


Man I sure do miss the country roads back home, lol.
 
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#3 ·
titanman2 said:
sounds to me you will be ordering this one. would it benefit for me to get a x pipe on my stock truck. all i have is a muffler and stock box mod.
I am sure the Dr gas X pipe would benefit you but at almost 200.00, the X pipe isn't exactly cheap horsepower and I think if performance is your goal, the money would be better spent on UpRev to begin with.
 
#7 · (Edited)
pinoytitan said:
good info papa_D... now i need to get that exhaust... lol.
You said it man, she is sweet.

SLOride said:
beware... DR. GAS has a raspy tone, but to me sounds bada$z
A little raspy wouldn't be a bad trade off for a smoother note and more power but I appreciate the insight.
 
#8 ·
Papa D, they said 2.5" for 350-400HP which is correct, but 95% of Titans running with several bolt-on mods are lucky to be pushing 290-310HP at the rear and maybe 320-340 at the crank. Those numbers vary depending on the dyno. What would have they suggested for pipe size based on the numbers I typed?
 
#9 ·
Nice. the questions you asked him re-affirmed what I've learned w/ my truck in using 2.25" B-pipes. Good questions too! Cant wait to see you stick that X on the truck
 
#11 · (Edited)
suddenurge said:
Papa D, they said 2.5" for 350-400HP which is correct, but 95% of Titans running with several bolt-on mods are lucky to be pushing 290-310HP at the rear and maybe 320-340 at the crank. Those numbers vary depending on the dyno. What would have they suggested for pipe size based on the numbers I typed?
I don't know because I asked them based on my Dyno numbers the last time I ran of 343.

I don't know if I believe that number but I have nothing else to go by so that's what I gave him.

I think 2.25" would be fine up to 350 but that's just an educated guess and of course you have some guys out there like RB's Titan doing great with 2.5" pipe and I did very well with 2" and 2.5" Y pipes

I think like he said, in a dual system, because it's a truck and you want to keep more low end power, 2.25" will be fine for me in the long run and probably OK for those with less HP as well.

shinermiller said:
Nice. the questions you asked him re-affirmed what I've learned w/ my truck in using 2.25" B-pipes. Good questions too! Cant wait to see you stick that X on the truck
I can't either, it's gonna be a blast.

pinoytitan said:
man, i gotta learn how to weld. is there like a quick basics class i can take to weld? i gotta learn how to weld so that my mods wont get higher cuz of welding. LOL. Plus i like to do my own stuff
Thrust Titan did the crash course in welding and may have a few pointers for you next time you talk to him.
 
#12 ·
I cant wait to finish my B-Pipes and get a damn tune. Be lucky freakin uprev supports yall... there are just as many people modding frontiers... yet NO love..
 
#13 ·
If you look at RB's mod list, he definitely made the right choce with the 2.5" B pipes. He falls into that 5% category, as you do and only a couple of others.
 
#14 ·
I like the way the Dr. Gas pipes are made. I'm holding out for one of their 2.25"/3" y-pipe merge collectors.
 
#16 ·
KINGMADE said:
I am going to go bigger on the pipes, there is a reason why hemi motors respond to cutouts, and our design is not far off...
so BANKS is in your future? thos are bigger pipes... cut outs are like $500 each... are there are any cheaper ones anywhere else?
 
#20 · (Edited)
shinermiller said:
I cant wait to finish my B-Pipes and get a damn tune. Be lucky freakin uprev supports yall... there are just as many people modding frontiers... yet NO love..
I do feel the love from UpRev every time I hit the gas man, lol.

I feel bad for you guys not having a tuning solution and maybe UpRev will step up with one.

suddenurge said:
If you look at RB's mod list, he definitely made the right choce with the 2.5" B pipes. He falls into that 5% category, as you do and only a couple of others.
I believe I could have gone larger but for the power I'm putting out now, I know the Nismo are a very good size.

Maybe with a bit more air in, I could perform as well as RB with the larger pipes but I am going to stick with the Nismo even if it hurts my performance somewhat.

I think the Nismo will flow well enough for 350 to 375 HP and I will do fine when I have added all the NA mods I plan to.

Maybe the Nismo exhaust will hurt NOS performance but I'll cross that bridge if I come to it.

KINGMADE said:
I am going to go bigger on the pipes, there is a reason why hemi motors respond to cutouts, and our design is not far off...
I don't know the exact design of the cutouts you speak of but I wonder if it has as much to do with header collector/exhaust pulse termination point as additional flow.
 
#22 ·
pinoytitan said:
man, i gotta learn how to weld. is there like a quick basics class i can take to weld? i gotta learn how to weld so that my mods wont get higher cuz of welding. LOL. Plus i like to do my own stuff
not t hard just make sure you dont have the machine set too hot ( high amp) or else youll be blowing holes in your pipes.
 
#23 ·
pinoytitan said:
the cutouts are right there at the headers... i blieve.
The proper place to let the collector see "open air", either with a cutout or a large change in pipe volume is 10-24" away from the collector.

10" is where I want mine because that will offer the most top end power whereas 24" away would be better down low.

I was all ready to work on header collector termination but that got put off for the Nismo True Dual project.
 
#25 ·
#26 ·
I had my H pipe cut in for 30 bucks at a muffler shop I am sure a shop would cut in a X pipe for not much more.It might not be as good as Dr.Gas but I bet you would see some gains.I know I got some gains from my 30 dollar H pipe.Performance wise and how the exhaust sounds.
 
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