david932 0 Posted March 7, 2007 i was wondering what power i should expect with the setup i am building i was hoping for just over 200bhp the spec is gti6 lump twin dcoe webber 40's kms ignition ecu also what exhaust system should i choose to match this for maximum power and torque gain. i need to keep it under 95db Share this post Link to post Share on other sites
Anthony 1,002 Posted March 7, 2007 I don't think you're going to see that kind of power on 40's as I don't think they'll flow enough for that even with the biggest chokes - you'd really want 45's. Still running standard cams? Share this post Link to post Share on other sites
david932 0 Posted March 7, 2007 I don't think you're going to see that kind of power on 40's as I don't think they'll flow enough for that even with the biggest chokes - you'd really want 45's. Still running standard cams? do you not think? i've heard of standard single t/b running that power, surely you would get more volumetric effiency with 3 extra throttles. yes standard cams, standard engine. only other mod will be a steel billet flywheel Share this post Link to post Share on other sites
boombang 2 Posted March 7, 2007 This is total crap science and assumes huge amounts but... I have read standard Gti-6 throttle body is 80mm with a 76mm pipe internal diameter. Assuming you using 40's with 36mm chokes. A 36mm choke gives 1017mm square area for the restriction Pipework on standard gives 4534mm square area restriction. This is 1133mm square per cylinder. Ok so in the plenum example you have losses from robbed charging etc, but you will have a bigger potential to flow per cylinder (assuming flow throughout all points of the inlet is the same, which it isn't but lets not get into that!). I'll be very interested to see what results you do get though! Share this post Link to post Share on other sites
zeolite 0 Posted March 7, 2007 I think 32mm chokes are the maximum for 40s. I run 36mm chokes in my 45s Share this post Link to post Share on other sites
Sandy 191 Posted March 7, 2007 Standard GTi6 TB is oval and mean diameter approx 62mm, so the plain area is about 3020sqmm, the spindle reduces this to about 2700sqmm. Because of the overlap of induction, the maximum demand is only really approximated to 2 cylinders at a time, so it's more consistent to compare to a pair of mutliple throttles rather than all four. This is approximately comparable in that case to 41mm chokes or 45mm multiple throttles. Share this post Link to post Share on other sites
david932 0 Posted March 7, 2007 (edited) This is total crap science and assumes huge amounts but... I have read standard Gti-6 throttle body is 80mm with a 76mm pipe internal diameter. Assuming you using 40's with 36mm chokes. A 36mm choke gives 1017mm square area for the restriction Pipework on standard gives 4534mm square area restriction. This is 1133mm square per cylinder. Ok so in the plenum example you have losses from robbed charging etc, but you will have a bigger potential to flow per cylinder (assuming flow throughout all points of the inlet is the same, which it isn't but lets not get into that!). I'll be very interested to see what results you do get though! who cares about potential? cross breathing will affect those figures significantly. if your gonna give out smart examples maybe you should get back on your calculator and work out how much WILL be lost Edited March 7, 2007 by david932 Share this post Link to post Share on other sites
boombang 2 Posted March 8, 2007 who cares about potential? cross breathing will affect those figures significantly. if your gonna give out smart examples maybe you should get back on your calculator and work out how much WILL be lost Er... ok... That was just very basic calculations. I wasn't trying to be smart. Your reply makes you come across as incredibly arrogant. Share this post Link to post Share on other sites
j_turnell 136 3 Cars Posted March 8, 2007 Enough of the throwing toys out the pram. As Anthony said you will ideally need 45's to make good power. May be worth looking into headwork and cams also. Share this post Link to post Share on other sites
david932 0 Posted March 8, 2007 (edited) Er... ok... That was just very basic calculations. I wasn't trying to be smart. Your reply makes you come across as incredibly arrogant. apologies. i really am sorry. The beer's got the better of me last nite. I'll remember not to post drunk again i think i must have read you post completely wrong and saw crap sience and amuses me . im dislecsic and sometimes read wrong sorry again Edited March 8, 2007 by david932 Share this post Link to post Share on other sites
Alastairh 47 Posted March 8, 2007 hahaha. we've all been there drinking and posting!!! Share this post Link to post Share on other sites
