vf34+methanol/headers
09 August 2009, 09:44 PM
#1
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vf34+methanol/headers
any benefit from 10% methanol map and gt spec 2 headers whilst running vf34 turbo apart from better spooling ~2-300rpm and ~10bhp gain-ie worth doing it now or leaving till i get new turbo like a md series one
martin
martin
10 August 2009, 01:32 PM
#4
If you are running the 3 bolt flange headers you will get a big improvement by replacing the existing uppipe with a "Special" which is purpose designed specifically for these headers to improve spool and torque.
The GT Spec tubular headers are not the best choice for a VF34 turbo.
The GT Spec tubular headers are not the best choice for a VF34 turbo.
10 August 2009, 05:28 PM
#5
If you are running the 3 bolt flange headers you will get a big improvement by replacing the existing uppipe with a "Special" which is purpose designed specifically for these headers to improve spool and torque.
The GT Spec tubular headers are not the best choice for a VF34 turbo.
The GT Spec tubular headers are not the best choice for a VF34 turbo.
Even when one does upgrade to the GT Specs, is it best to junk their up-pipe and replace it with one of your OEM ported jobs (presumably it's narrower than the GT Spec item?) for quicker spool up?
Last edited by joz8968; 10 August 2009 at 05:30 PM.
10 August 2009, 06:01 PM
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nice gains on methanol!!was it mapped for that i presume??
interesting re headers i thought tubular was the best way to go as even ported headers have their limits-i have a vf34 turbo at present and plan to upgrade to likely MD321 next year so would it be better to wait till i get turbo before changing headers??
i thought the gt headers came with uppipe already or are you recommending a different uppipe??
thanks
martin
interesting re headers i thought tubular was the best way to go as even ported headers have their limits-i have a vf34 turbo at present and plan to upgrade to likely MD321 next year so would it be better to wait till i get turbo before changing headers??
i thought the gt headers came with uppipe already or are you recommending a different uppipe??
thanks
martin
11 August 2009, 07:42 AM
#7
There is no set breakpoint where fitting tubular headers becomes a clear choice or vice versa. However, GT Spec tubular headers on a VF34 would not be a choice I would make. Spool is moved up the rev range by a big margin. This has the effect of putting your foot down at say 3000 rpm and then waiting for something to happen. Ported O/E headers and matched uppipe will improve spool and responsiveness noticably over the originals as they come from Subaru. The car is crisper with more torque right across the rev range.
The GT Spec headers come with their own uppipe but I have designed a replacement uppipe which will improve the performance substantially and these have been fitted to numerous applications all the way from 380 bhp to nearly 600 bhp and some of the improvements have been astounding. Like 500 rpm earlier spooling. This margin will not be repeated in all instances but the improvements are such that once the replacement uppipe is fitted the fuel map needs attention as the car will need fuel in the new spooling area and generally across the rev range.
More fuel = more power.
The GT Spec headers come with their own uppipe but I have designed a replacement uppipe which will improve the performance substantially and these have been fitted to numerous applications all the way from 380 bhp to nearly 600 bhp and some of the improvements have been astounding. Like 500 rpm earlier spooling. This margin will not be repeated in all instances but the improvements are such that once the replacement uppipe is fitted the fuel map needs attention as the car will need fuel in the new spooling area and generally across the rev range.
More fuel = more power.
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11 August 2009, 09:08 AM
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probably best me just getting second methanol map on vf34 then when getting new turbo get gt 2 headers with your uppipe as 500rpm should easily offset bigget turbo
thanks
martin
thanks
martin
11 August 2009, 09:43 AM
#9
Thanks harvey - I've always wanted a re. yours vs GT Spec. 
I have a set of ported OEM headers/up-pipe to go on with a FMIC/IK/740s on my MY93 WRX (with TD05 16g). I take it that these ported jobs will be just perfect for this level of tune i.e. up to c.350bhp when mapped?
However, there'll be a chance later on that I'll want to go to 400+ on a S206, MD321T or your own HS420... would it be better to swap over to the GT Specs + your specialised up-pipe at that point, then?
I have a set of ported OEM headers/up-pipe to go on with a FMIC/IK/740s on my MY93 WRX (with TD05 16g). I take it that these ported jobs will be just perfect for this level of tune i.e. up to c.350bhp when mapped?
However, there'll be a chance later on that I'll want to go to 400+ on a S206, MD321T or your own HS420... would it be better to swap over to the GT Specs + your specialised up-pipe at that point, then?
Last edited by joz8968; 11 August 2009 at 10:29 PM.
11 August 2009, 06:54 PM
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nice gains on methanol!!was it mapped for that i presume??
interesting re headers i thought tubular was the best way to go as even ported headers have their limits-i have a vf34 turbo at present and plan to upgrade to likely MD321 next year so would it be better to wait till i get turbo before changing headers??
i thought the gt headers came with uppipe already or are you recommending a different uppipe??
thanks
martin
interesting re headers i thought tubular was the best way to go as even ported headers have their limits-i have a vf34 turbo at present and plan to upgrade to likely MD321 next year so would it be better to wait till i get turbo before changing headers??
i thought the gt headers came with uppipe already or are you recommending a different uppipe??
thanks
martin
12 August 2009, 12:05 AM
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similar turbo, mine was a vf35. Fitted GT spec 2 headers with supplied up pipe and my turbo spooled up an easy 3000 rpm earlier.
been told that the vf34 is good for approx 10bhp over the 35 and I was running 370 bhp 360 lbs-ft of torque was on full boost of 1.5 bar at 2700 - 2800 rpm with 10% methanol
been told that the vf34 is good for approx 10bhp over the 35 and I was running 370 bhp 360 lbs-ft of torque was on full boost of 1.5 bar at 2700 - 2800 rpm with 10% methanol
Last edited by G.Mac; 12 August 2009 at 12:06 AM.
12 August 2009, 08:00 AM
#12
500 rpm was one particular example, Paul Armin on a 2.5 somewhere between 550 and 600 bhp. Different cars respond differently but we have not fitted a replacement performance uppipe that did not result in a worthwhile improvement.
Joz: For what you are doing for now I would stick with ported headers and matched uppipe.
Mac, is this a 2.5?
Obviously your previous setup was very laggy 
Joz: For what you are doing for now I would stick with ported headers and matched uppipe.
Mac, is this a 2.5?
and my turbo spooled up an easy 3000 rpm earlier.
12 August 2009, 10:41 AM
#13
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similar turbo, mine was a vf35. Fitted GT spec 2 headers with supplied up pipe and my turbo spooled up an easy 3000 rpm earlier.
been told that the vf34 is good for approx 10bhp over the 35 and I was running 370 bhp 360 lbs-ft of torque was on full boost of 1.5 bar at 2700 - 2800 rpm with 10% methanol
been told that the vf34 is good for approx 10bhp over the 35 and I was running 370 bhp 360 lbs-ft of torque was on full boost of 1.5 bar at 2700 - 2800 rpm with 10% methanol
will get run in map as new engine on murt then get 2 maps 280 and plus methanol on 2.1 stroker then get a MD321m possibly
martin
Last edited by p1doc; 12 August 2009 at 10:59 AM.
