mk2 jetta KR conversion help

[vee-dub90]

I am going to be rebuilding a kr for my Jetta. and i am plaing on using

wossner high comp pistons, uprated rods and bolts, knife edged crank and lightened and balanced, balanced rods, and flywheel, twin 45 dellortos, std ignition with uprated plugs and leads. newman 288 cams, possibly uprated valves and springs. uprated clutch, better oil cooler.

i will also do some headwork i.e polish and gas flow it. and running a 4 branch with full stainless system using only a backbox.

is it true that if i still run the ecu for the ignition i can keep a rev limiter?

also if anyone has any tips/ advice i would be very greatful

[mk2bal]

My tip would be to do the above to an abf/9a, not a kr.

[Neo Badness]

My tip would be to do the above to an abf

Carb's on an EFi? 45's sound great but not optimal.

 better with ITB's and standalone management but that's potentially getting expensive. ABF would yield more power either way. Although KR's are tough units and can be had for sweeties as everyone is going ABF.

Rather than spunking a healthy wodge on an engine build why not get it in and running and that way you can decide what needs upgrading?

ABF on OEM management would still be amusing.

[DOA]

You need to look at a few things here.

1: Dont use a KR as a base, waste of money and an ABF will be a far better base.

2: Yes you might get away with using the stock ignition to keep a rev limit but there are two problems here, the first being the rev limit itself and the second being the use of high comp pistons. Dealing with the rev limit, there is zero point to uprating the rods and pistons if your going to keep the stock rev limit, its a complete waste of money as you will still be making power past your stock rev limit with the cam, head and inlet mods. Dealing with the high comp pistons bit, you will have to be really carefull to avoid knock with a raised compression ratio and the stock ignition setup will probably not be anything like what you want to avoid this. An ABF K-jet ignition system may be better as it may (correct me if im wrong here) have knock detection built into the system. Either way, bearing in mind the mods you are planning, stock ignition is just going to lose you power.

3: Dellorto's may sound good and look good to your eyes but throttle bodies will make much better power in conjunction with a standalone ECU. Your just wasting money doing it that way but if thats what you want...........

4: If you fit a windage tray there will be no need for the knife edging of the crank. Windage tray cost, £20 from ebay, knife edging the crank??

5: Uprated plugs and leads, dont get me started, they dont work out on a cost to performance basis, the leads "might" give you a single extra horsepower but I have seen as many independant tests that lose power. Same goes for the plugs, irridiums might give you a tad more power (unlikely without a turbo) and do so for longer but I look at it this way, at least if you fit stock plugs, you can then afford to change them more regularly without spending any more money whilst keeping a better eye on the condition of your engine by servicing it more thoroughly at oil change time.

6: Doubt you need uprated valves or valve springs, just replace with new if your worried about them. Better yet, speak to your head man and ask his advice.

HTH

[Neo Badness]

4: If you fit a windage tray there will be no need for the knife edging of the crank. Windage tray cost, £20 from ebay, knife edging the crank??

I didn't know that fitting a windage tray would eliminate the need for a knife edged crank? Would doing both, money aside, not be "better". I do know that you can buy the windage tray cheaper from VW as it's a stock part on 1.9d caddy.

[DOA]

The whole idea of a knife edged crank is that the crank doesnt have such a hard time splashing through the oil in the sump/the oil flying around in the sump area in cornering etc (as an example, Dave Walker mentioned in CCC once that Rover Tomcat racers used to run with low oil levels to stop this occuring and thus reduce losses = more power to to the wheels!). Essentially this stops being such an issue when you have a windage tray to effectively seperate the sump reservoir from the crankcase proper as the volume of oil the crank will be forcing its way through is significantly reduced. Money no object you would use a very different crank that got you round the problem but yeah, you would probably gain a tad through knife edging the crank too I suppose, its just a case of are you doing it to say you did it or are you in an ultra competitive race class where every single bit of extra power helps.

[Neo Badness]

The whole idea of a knife edged crank is that the crank doesnt have such a hard time splashing through the oil in the sump/the oil flying around in the sump area in cornering etc (as an example, Dave Walker mentioned in CCC once that Rover Tomcat racers used to run with low oil levels to stop this occuring and thus reduce losses = more power to to the wheels!). Essentially this stops being such an issue when you have a windage tray to effectively seperate the sump reservoir from the crankcase proper as the volume of oil the crank will be forcing its way through is significantly reduced. Money no object you would use a very different crank that got you round the problem but yeah, you would probably gain a tad through knife edging the crank too I suppose, its just a case of are you doing it to say you did it or are you in an ultra competitive race class where every single bit of extra power helps.

  cheers for the knowledge.

[Diamond Hell]

An ABF K-jet ignition system may be better as it may (correct me if im wrong here) have knock detection built into the system.

The wha?  Do you mean the ABF Digi3.2 ignition system?  That'd work - it has dual knock sensors and you can probably fool the injection side of things.... but to be honest unless you're going to ITBs then keep the Digi 3.2 wholesale. 

There is some suggestion that you could even keep it with ITBs, provided you have a vacuum resevoir to take the pulses out of the vacuum for the MAP sensor. gotta be worth a shot.

[DOA]

Consider myself corrected  .

[tech1889]

Consider myself bamboozled 


Good info there guys nice to know