With the standard valves, the car will run out of puff early. The head just seems to choke up & cant physically flow enough air that the bottom end is trying to shift. Mine did exactly this & wouldnt better 135BHP at Stealth.. The Big exhaust valves & associated flowing work make a lot of difference. Max power moves to around 5800-6000 & the car will pull cleanly to the limiter. The extra stroke of the 2L means it will also tolerate a hotter cam. This is why I found the TSR 202 too mild... The article I mentioned was all carried out at Dave Walkers workshops (Of CCC fame). I have also had several cams in my car for comparison, hence my scepticism about how much power they give. Having said that, on an 1800, the TSR 202 & GS2H felt the best & improved revviness no end! Edited by: chrismc
Before you spend too much dosh, i have an unwanted high lift cam 275 and vernier pulley to fit mk2 pb engine 8v digi. 140 + post. my reason have a 16v now.
Ive seen the graph Tub & dont dispute what it says.. All I can think of, is that its easier to adjust the fuelling to a new cam in a K-Jet car than a Digifant, as a digi ideally requires a re-chip to match the fuelling. Therefore, to achieve anything like your power gain would cost far more with a digifant car, as the ECU needs to be mapped to suit the cam..
Just checking... Yeah, i do think the K-Jet responds better to the mods.. Digi's never seem to make the power as easily.
That's because the Digi only fuels according to the amount of air being sucked in until the AFM is pinned open, after which it reads straight from the map. The AFM is wide open way before the engine is doing any sort of decent RPM.
What sort of torque figure was yours putting out before you did more head work Chris? Mine is doing exactly what you say, running out of puff early, you can really tell its struggling. In an ideal world i should have had more headwork done, but hey you live and learn That said though I am quite happy with the results at the moment. I should have some RR results next weekend
Having owned both K-Jet and Digi 8v's in the past, I can vouch that the K-Jet is *far more* reponsive. My 1st GTI , a 87 k-jet 8v was a flyer , I was SO disappointed when I bought an '88 Diduphart, didn't keep it long. Still damn impressed with Steve McIntyre's mk2 k-jet 8v Road Saloon that was at Donny, Apparently it had a Schrick cam and BV head, think TSR did the work, it flew! Edited by: G_V_K
Yeah, I kind of get the impression that the Digifant injection responds poorly to mods too, mines just a simple twin choke Weber Carb and it appears to be working fairly well - comparable to a digifant (without the sudden drop in power at 5500 rpm or there abouts). Would be very interesting to see what power your motor would make on K-jet ChrisMC.
With the standard valves , TSR 202 cam (268/272) & all the flowing work it made 135BHP & 137lbs/ft @ Stealth. Maximum power was at about 5500 despite the longer stroke, which is similar to a std. 1800, showing that the flowing was helping....but even so it just kinda hit a brick wall.. Moving the cam timing did very little as did swinging the ignition timing [:^(] Since then ive got a Big Valve head, lightened flywheel & TSR 203 (282deg) cam. Now its much better. I still think ideally it needs a remap or piggyback ECU to bring it all together. At TSR it recently did 122atw, which is similar to what several KR 16vs & exactly the same as one ABF 2L 16v mk3 did at their recent RR day. I look forward to seeing how this equates at Stealth this weekend at the shootout..... In an ideal world perhaps I too would have bought a valver
I bought a Cacks Power guide to modding the Golf last year, Its got the kjet 8v 0-60 as 8.4 seconds and the digi as 9.3! I would say like for like the kjet 8v is quicker but surely not that much quicker! Viva la Kjet
K-Jet is a performance based injection system, dijifant is economy based. K-Jet is much better as has been discussed. They even changed the gearbox in Dijifant cars so that they could pull 60 in second to imporve the time
A digifant car can compete with a K-Jet...its just that it needs remapping each time any serious mods are done. I wouldnt say a digi feels slower to drive, but definitely isnt as responsive as a K-jet..until you re-chip it that is & by pass the overrun cut off. The digifant system was definitely a forward step by VW, but is certainly comprimised in a few areas, especially when it comes to tuning!
hehe chris you must be in the same boat as me - the cgti forum helps the work day go a little quicker bit bummed off, might not be able to make the next wilts meet as im working in scotland for the day. but with any luck the shed should be two litered for the feb meet Im gunna have to go with standard valves as I cant afford the head work [:^(] If the digi head functions with kjet im gunna see If I can get one as the copy of ETKA that Will did for us proves the inlet valves are bigger. Just gotta decide on a cam profile and shes on the way!
