how much hp going from 3 to a 3.5" dp?
01-28-2007, 07:38 PM
#1
how much hp going from 3 to a 3.5" dp? set up is twin gts70's on a 408 with 3" dp's. when i put the truck together i thought i only had room for 3" dp's but now that is is done i see there is room for 3.5". does anyone have any idea how much hp upgrading to 3.5" dp's might be worth while running at ~20psi? this is open dp's about 2' long.
01-28-2007, 08:16 PM
#3
Hhmmmm. If you had just a 6.0L I'd say don't bother. But since you have a 408" turbo motor I would think power would benefit from a larger DP. How much I have no idea. Also, the larger DP should help spool time, which would generate more power sooner.
On an unrelated topic, since keeping weight on the front wheels is important on the 4X4, what about the iron LSX block
? A 454" twin turbo motor should get you in the 9s no problem 
. And that could really use a pair of 3.5" downpipes 
.
On an unrelated topic, since keeping weight on the front wheels is important on the 4X4, what about the iron LSX block
? A 454" twin turbo motor should get you in the 9s no problem . And that could really use a pair of 3.5" downpipes . 
01-28-2007, 09:31 PM
#5
FormerVendor
Open downpipes 2' long? I would be suprised if you picked up anything really.
The car we made 1162rwhp with had dual 3in to the bumper and it was very efficient in terms of HP vs Boost.
The car we made 1162rwhp with had dual 3in to the bumper and it was very efficient in terms of HP vs Boost.
01-28-2007, 09:38 PM
#6
[QUOTE=INTMD8]Open downpipes 2' long? I would be suprised if you picked up anything really.
[QUOTE]
thats kind of what i was thinking but i really dont know. hmm, i just had an idea. kind of getto but a good test. i could put a set of up facing 3.5" 90's on the turbos and pull the hood next time i goto the dyno. i think i have the tubing and flanges to try it. test back to back runs with both set ups. if i gain then i could think about upgrading my downpipes.
[QUOTE]
thats kind of what i was thinking but i really dont know. hmm, i just had an idea. kind of getto but a good test. i could put a set of up facing 3.5" 90's on the turbos and pull the hood next time i goto the dyno. i think i have the tubing and flanges to try it. test back to back runs with both set ups. if i gain then i could think about upgrading my downpipes.
01-28-2007, 09:42 PM
#7
FormerVendor
[QUOTE=parish8][QUOTE=INTMD8]Open downpipes 2' long? I would be suprised if you picked up anything really.
thats kind of what i was thinking but i really dont know. hmm, i just had an idea. kind of getto but a good test. i could put a set of up facing 3.5" 90's on the turbos and pull the hood next time i goto the dyno. i think i have the tubing and flanges to try it. test back to back runs with both set ups. if i gain then i could think about upgrading my downpipes.
Just get a video
thats kind of what i was thinking but i really dont know. hmm, i just had an idea. kind of getto but a good test. i could put a set of up facing 3.5" 90's on the turbos and pull the hood next time i goto the dyno. i think i have the tubing and flanges to try it. test back to back runs with both set ups. if i gain then i could think about upgrading my downpipes.
Just get a video
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01-28-2007, 09:51 PM
#8
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[QUOTE=INTMD8][QUOTE=parish8]
LOL. yes. do get a video of that one. by the way hows the build?
Originally Posted by INTMD8
Open downpipes 2' long? I would be suprised if you picked up anything really.
Just get a video
Just get a video
LOL. yes. do get a video of that one. by the way hows the build?
01-28-2007, 10:07 PM
#9
truck has been sitting for a month or so, working on some other stuff but i hope to be trying it in 2wd next year. drop about 600lbs. beef up the rear and run some 315/60/15 mt dr's. i still want to keep it a "street truck" for another year or so. next year maybe try the lsx block, more power, 4 link and some big tires......
01-28-2007, 11:32 PM
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i would think with a motor that big you would want something bigger, hell tiago has 70's on his 346. but to each his own, good luck buddy i love following the work progress on this thing
01-29-2007, 11:31 AM
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Originally Posted by parish8
bigger than twin 70's? 
i am lifting the heads and still have about 500more hp avaliable from the turbos. if anything i have a little more turbo than i need right now but i hope to grow into them.
i am lifting the heads and still have about 500more hp avaliable from the turbos. if anything i have a little more turbo than i need right now but i hope to grow into them.
im just kidding, if your not having a problem then dont fix something thats not broken
01-29-2007, 04:05 PM
#17
Originally Posted by NA$TY-TA
Hell yeah....
Jim are you lifting the heads on the new setup or the old setup???
@ 22 psi?? how much timing and was it on the Dyno or the track??
Kyle
Jim are you lifting the heads on the new setup or the old setup???
@ 22 psi?? how much timing and was it on the Dyno or the track??
Kyle
i am near the limit of my fuel system and was only running 114 octane so it is posiable that better fuel and more of it will help me out. the wide band was still showing in the 11's but the log on my fp was floating around a little up top.
i am going to step up to a fuel cell and bigger lines. i am still on the factory fuel lines
. soo... drop 600lbs. put a fuel cell in the very back of the bed, run bigger lines and bigger pump and run 118 octane fuel. if i can get it to hook it should be quite a bit quicker.
01-29-2007, 04:07 PM
#18
i was running around 21deg with the 114 octane. when i gut up to 20psi i backed it off to 18-19psi and still had the same problems. on the dyno it was picking up power all the way to 23deg at least. thats as far as i turned it up.
01-29-2007, 04:44 PM
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Originally Posted by parish8
with either set up when i go over 20psi i start to have problems. pushing water and eventualy pushing out the head gaskets. on the dyno i am fine(dynojet).
i am near the limit of my fuel system and was only running 114 octane so it is posiable that better fuel and more of it will help me out. the wide band was still showing in the 11's but the log on my fp was floating around a little up top.
i am going to step up to a fuel cell and bigger lines. i am still on the factory fuel lines . soo... drop 600lbs. put a fuel cell in the very back of the bed, run bigger lines and bigger pump and run 118 octane fuel. if i can get it to hook it should be quite a bit quicker.
i am near the limit of my fuel system and was only running 114 octane so it is posiable that better fuel and more of it will help me out. the wide band was still showing in the 11's but the log on my fp was floating around a little up top.
i am going to step up to a fuel cell and bigger lines. i am still on the factory fuel lines
. soo... drop 600lbs. put a fuel cell in the very back of the bed, run bigger lines and bigger pump and run 118 octane fuel. if i can get it to hook it should be quite a bit quicker.
01-29-2007, 05:13 PM
#20
Subscribing.
I'm interested also. I'm running 17 psi boost, pulling 146 mph at 3750 lb, and making 700 rwhp, all on a single 3" downpipe. I can fit a 3.5", but it will be very tight, difficult, and make the car harder to work on. If I can't pick up 50 hp, it's not worth it for me.
I'm interested also. I'm running 17 psi boost, pulling 146 mph at 3750 lb, and making 700 rwhp, all on a single 3" downpipe. I can fit a 3.5", but it will be very tight, difficult, and make the car harder to work on. If I can't pick up 50 hp, it's not worth it for me.