Hiya guys, looking Into installing ITB's ( bike carbs ) to replace the pierberg carb on my 1.6 ( 1595cc ) mk2 golf! EZ engine code.
Now, I know I'll need a fuel pump and a custom inlet manifold! But I'll also have to have the jets re-drilled! Can anyone tell me what sizes need to be drilled or what calculations are needed to find out the correct sizes!
I'am also fitting a camshaft from a 1.8 8v gti ( PB engine code ) and a dizzy from a kjet 1.8 8v gti engine ( EV engine code ) if this makes any difference!
Do the manifold first, belive me it is something difficult. in a counter flow head. what are your carbs?. you have so long way to go. Drilling jets is another story depends on your engine specs and carb size. i wouldnt put something bigger than 38 mm (less if possible) on a 1.6 lt engine. but i would start with drilling 1.6 mm , you have to find a wide band o2 meter. Keep in mind unless your engine has further upgrades like an agressive cam, head work headers etc. you can not see the benefits of bike carbs exept the sound. you can use a dgav or dgas weber insted , much more easier.
I have 1998 Suzuki gsxr600 carbs! First of the srad bikes! I think they're 36mm!! It will have a cam from a PB 1.8 8v mk2 golf gti engine! The cylinder head will be from the same engine! I will be sending the bolted on carbs to a tuning company to be tuned!
So far my research follows me to beleving that I need one vacuum port for the servo & dizzy!
be careful about the compression ratio when using that head.i am alsousing gsx 600 carbs. but carbs must be tuned on car you can not just send your carbs and get it tuned. there are soo many factors that effects the fueling.you can just just add some compression by decking the head.i would not recommend going more than 1:10. the manifold is the main problem than. i would recommend start with a diesel manifold, cut it about 5cm away from the flange , and make 4 tubes to match with your carbs ,and weld them to pre cut diesel manifold. the runner tube length must be around 14 cm as ı remember. this is the maximum length that leaves some space between your fire wall and carbs.take your crbs and mani to a welder . weld a 15 mm tube to the 1st runner for the brake servo. make good isolation to the exhaust manifold not to suck hot air.nside. be careful about the fuel peressure. ask anything you need.
I belive for the best power the distance must be from inlet valve opening to butterfly opening should be 320mm! I'am going to buy some 180 bends for the manifold, so that it won't be near the firewall.. I'm bolting all the carbs and nessercery bits to the car then sending the car off to rolling road! The head is being ported and to a very high standard too! I'am also having trouble with getting 98 gsxr600 fuel pump too, do you know what other fuel pump I can use? Tryin to steer away from using a facet fuel pump and seperate regulator!
Well ı dont recommend 180 deree bents , 320 mm runnerlength iis for the 2nd harmonic and power band is also very inportant. you are using a ported head and ı assume u are using a cam around 270 degrees the peak power figures will be arund 6300-6500 rpm . İf you design your manifold for this RPM according to my calculations the legth should be arund 27 cm from the valve head .NOT the manifold length its self.be careful about it. İf you send PM your email İ can send you the photos of my build. I can not load pics from my work. At 27 cm the clearence of your carbs and fire wall are enough to put tiny filters.By the way if you make a 180 degree bent you can not reach the mixture adjustment screws! it woulbe painful to take out the carbs at each try.
The fuel pump can be from r1 as well. But i used a mechanical cheap suzuki pickup pump from 90's and route a by pass line from the pump to carbs, goes to the fuel tank, and put an adjustment valve on the route to tank. i set the pressure with an inline pressure gauge using the by pass return valve all very cheap accesories from hardvare store . İt is working very well . you can do the same with your mechanical standard pump but the pressure changes with the rpm of your engine.
I will be using the standard gti 8v PB camshaft! I was told about the manifold length by the guy who is porting & polishing my head, he also told me about using 180 bends. I think I need about 4.5 PSI fuel pressure, but If an R1 pump works that'll be great! If you could pm me, that would be great