i have this header for a VW. these idiots on vortex have no clue about custom/ good quality parts. i came hear b/c i know you guys do.

basiclly i am building a budget build 2.0L and putting it in a 83 rabbit. i am running a set of zx9 ninja carbs and a techtonics cam. here is the specs on my 2 cam choices:

Duration Duration Duration Duration Lift Lobe In. open Notes
Advertised @ .020" @ 1mm @ .050" Center @ .050"
In./Ex. In./Ex. In./Ex. In./Ex. In./Ex.


276° 109 074 $200.00 276° 250° 238.5° 234° .449" 110° 6.9° BTDC Rough Idle good W/Early CIS/Carbs*

Race 288 109 068 $225.00 288° 261° 249.5°/248.5° 245°/244° .460" 110° 12° BTDC Rough Idle *


i milled the head and raised compression to around 11:1- 11.25:1. i am making my own manifold out of schedule 40 alum pipe from mcmaster. it is the same size id as the carbs, 40mm. i am running a 1" thick flange on head to gradually choke down runners to 34 mm-stock port size. i was planning on running 2.5" exhaust.

ok now to the point. you know the set up now. i got this header on ebay for real cheap. this thing came inthe mail today, and wow, 1.75" collector. its a gay crush collector of course and i already was considering a burns unit or the like.

the measurements that i got was 23-24" runner length, 1.75" collector, 1.5" runners. i talked to guy that builds a few headers and he said to go witha 3" collector and runners 28-32" in length.

i got to see if you guys think i should buy a nice merge, lengthen the runners, what size merge. i was also thinking of just adding a 2.5" pipe to the collector, marking then removing neccassary left over outlet material. then i was thinking if i do that maybe i should keep part of it there for reversion, like stepped primaries or neck down like a scavange effect.

this post is kinda long so thanks for bearing with me.

 

i cant believe 178 people looked at it, and no one commented on my suggestions.

 

What head are you running the 8 valve? and what pistons did you use?

 

aba complete motor. bottom end untouched. just milled head for cr

 

2.25" or 2.5" max for the exhaust. whats the deal with the guy telling u to run a 3" collector? is he also saying to run a 3" exhaust?

 

well my h22 had a 3" also. i am guessing b/c a crazy duration cam and carbs and cr of 11:1

 

i can see why u would run that with an h22 (its bigger and the head has much better flow) but an aba head flows approx 140 cfm in stock form. even though u would be running a huge cam and the carbs that would still be over kill for that engine. where the bend is right before the collector, why dont u chop it, lengthen the runners to around 28" and add a nice quality merge collector instead of that pos thats on there. thats my opinion. im not sure if a step would do any good with this scenario.

 

yea thats kinda what i was thinking

 

look at the tectonics race header for comparison. (this is for the mkI 8v cars). not quite the same basic design but u get what it should look like in the mkI chassis because of the lesser clearance between the engine and firewall than the mkII and III cars.



compared to a mkII or III





Modified by all_motor_mike at 2:59 AM 5/13/2006

 

Yeah, the collector is what sticks out to me the most right off the bat. The angle is far too steep along with the fact that it's an "old school" method by wrapping the tubes with sheet metal and pounding yourself a collector.

Aside from that though, without knowing the rod length/stroke and the intended rpm range, the length is a pure guess with some outside past experience influence. The piston speed is a certain factor in calculating the scavenging needs of the motor from an exhaust standpoint.

 

here is some 8V info for yah. the stock flow #'s were with stock size valve. the ported #'s were after some portwork, valvejob, and oversize techtonics valves. port volume wasnt greatly increased. port velocity is pretty good but the heads are sure lacking.


intake side
lift stock intake ported intake increase
.050" 24.5 cfm 33.1 cfm +20.98%
.100" 47.1 59.2 +20.4%
.150" 69.6 83.8 +14.2%
.200" 92.2 106.1 +13.1%
.250" 108.1 123.3 +12.3 %
.300" 121.2 136.4 +11.14%
.350" 125.4 143.1 +12.35%
.400" 126.5 143.3 +11.72%
.450" 127.4 142.8 +10.78%

Exhaust results

lift stock exhaust ported exhaust increase
.050" 15.3 cfm 23.2 cfm +34%
.100" 36.6 45.8 +20.1%
.150" 52.3 72.6 +28%
.200" 70.9 87.6 +19%
.250" 81.3 96.6 +15.84 %
.300" 87.1 99.9 +12.81%
.350" 90.6 101.2 +10.47%
.400" 92.2 101.7 +9.34%
.450" 93.1 102.2 +8.90%

you probably dont need a 3" collector on an engine that doesnt flow over 100cfm on the exhaust side. just a guess

 

bore- 82.5 mm
stroke- 92.8 mm
dis- 1984 cc
rod length- 159 mm
r/s ratio- 1.71
piston speed at 7000 rpm (redline is 6250 i believe)- 4262 fpm

with the big cam and carbs i figured peak power would be made around 7000 rpm's

theres the info lets see what u came up with RC000E (im not questioning u i actually want to see what u come up with)

 

ok have we decided then maybe lengthen the runners to 28" inch if space permits? and a 2.5 collector? where can i get collecotors? i know burns has them , but thats a little too much money for the budget build.the most i want to spend is about $100 for thae collecotr and 1.5" pipe

and i know i want the world for free.

 

s&s headers here in glendale Az............ heres they're page for the 1.5" merge that they make, its in ur price range too. not burns quality but definitley not a p.o.s.

http://www.headermania.com/mm5...RSPMC

 

thats awesome. i am very pleased with the price. as soon as i fiind a little extra cash i am getting that.

 

Forgot about this thread.....just happened to do a search

I'll get back to you, I am out of town right now...all my stuff is back at the house.

 

You don't need a 3 inch collector.....whoever told you that is nuts. I run the TT long tube race header on my car, and I think its about the best OTS header there is. The only changes I would make to the TT header is to shrink the collector a bit. You're collector is 1.75 inches, which is about perfect...after the collector, make a smooth but short (about 6-8") transition into a 2.25 or 2.5 inch pipe.

PS: the 288 cam has a pretty mean idle.

 

i may try to make my own collector. i have a bandsaw that i may be able to borrow. i am going to lenghten it as well.

i have my intake manifold ready to be welded up already. milled it out this afternoon and cut the manifold runners tonight.