1.8 KR on ZX9R Bike carbs - How much power

Hi
I thought I would ask how people have got on with theirs
I had my tuned today on the Rolling Road at John Sleath Racing and it is mental.
I did the conversion and it has a standard exhaust, ZX9R Fuel pump and has had some extensive headwork - Thats all.
My power output was ??????

Let me know yours and I'll tell you mine

Id guess at 210 but i hope its a lot less as my mate has a very simular setup in his and id love to wind him up lol

Good guess but no cigar, whats your mates running at??

Bit of an open question but how easy was the conversion to do ? any tips or advice greatly appreciated as im really tempted to give this a go in my mk 1 jetta 1.6gl carb.

Cheers

Very open question, If you are already on carbs and arent swapping engines out then easy really,
I only have the knowledge for the KR engine the 8v are more dificult cos the inlet manifold is a ball ache i think not a lot of space at the back of the head (KR inlet at the front). I got most of the info needed from this forum and clubgti and with some help from some good people on these forums

just tell us lol i'm just considering doing this, only did the conversion 2 weeks ago but don't know if i should bike carb the kr or do a g60 swap now

if your bhp is ok i'll leave the kr in and keep the g60 for a caddy i got my eyes on

Matt

My mate is running a abf bottom with kr head port&polish with s/s 4-1 mani, bog bros mani with r1 carbs, lary cams. unknown BHP but id be guessing more than yours?

So whats yours putting out? can you scan the graph so we can se how the powers delivered?

KR = 139 BHP
P+P = +10 BHP
Carbs = +20 BHP


So I'm going to guess at about 170ish?

lol for some reason i had a kr at 160bhp in my head

I retract my earlier guess and now state 185 bhp

Lee_dub said

Carbs = +20 BHP

Never understood why adding carbs over injection would increase the bhp the engine produces ?
Surely a more precisely controlled and mapped air fuel mixture would produce more power ?

Well I am not not saying because of showy off reasons, the truth is I dont believe the figures.
I have driven some very powerfull cars in my time through work and stuff and I am totally amazed at the output on the road that I am getting, My brother inlaw drives a mk3 20vt with extra work and is showing 362 at the wheels - Its mental. He drove it yesterday and said it was very cool and he was impressed.

My engine was from my mk2 valver and was rapid but this is stupidly fast I am over the moon with it.
But I dont believe the figure from the Rolling road, I will have to save some pennies and get a run on another road. Bloke who did the work on tuning builds race cars - Real Race Cars.. 1500 bhp race cars.
It is so much better on the carbs than the standard Kjet injection.

He guy at the race shop has tuned a 1.1 polo with cbr600 carbs, its initial output was 40ish bhp and ended up being 80bhp so this shows you can achieve an extra 40bhp from carbs,

And Matt finish the KR of you wont be disapointed..

My 8v G60 gave 190bhp on the Midland VW rollers and in its current 16vG60 configuration gave 230bhp, all from a Digifant setup, mind you it is not running right on the BBM chip. I will be vising Jabba very soon…

Lol on doubling the bhp with just carbs !!

lhasadreams said

Lee_dub said

Carbs = +20 BHP

Never understood why adding carbs over injection would increase the bhp the engine produces ?
Surely a more precisely controlled and mapped air fuel mixture would produce more power ?

It wouldn't normally, just K jet is garbage so a little man pouring fuel in the cylinders by hand would be an improvement

Go on then mr brutal- what's the bhp output of yours?

Said mate of funkstar would love to know roughly what power output theses things supposedly push out- seeing as I'm the one with unknown bhp I'd like a ball park figure for the time being until it's fully ready for a rolling road session!  :wink:

What should I do, Hmm what I was after was to find out what people with a similar spec to mine got out when they had been on a rolling road, then I could make a comparison of there result and mine, like I say the figure I got was not what I expected, but the drive on the road is what I expected. A troublesome conundrum…..
What If I told you it came out 90bhp you would be disapointed but then I told you I kicked a scoobies arse - what would you believe the figure or the drive??

There's variations in the way rolling roads read power figures anyway, so they can't be totally trusted sometimes. Also some tuning firm's rolling roads seem to deliberately read high, so they can chip a car, then show the customer the 'improvement' over a stock figure.

The best way to use the rolling road is to do a basic setup of the engine (or even do a "before" engine conversion run) then do a tweak or 3, then go back to the same place and re-do it. Also measure a number of other things at the same time, mainly AFR using a wideband, this way you can identify what causes, eg a dip in the power at a certain point.

I took my car for 2 rolling road sessions, the first one an ignition problem unknown to me was identified so the car didn't do a full run (but I'd have never found it myself, the rolling road puts the car under load). The second one was a couple of actual runs with the wideband AFR probe in, and it identified leaning out of the fuel mixture at the top end. I later purchased my own AFR gauge. I've never done a 3rd run because the car's going fine and never felt the need.

Doing rough comparisons like "kicked a scoobies arse" is extremely difficult on the public roads - for example, how do you know he even used full throttle, or didn't give way to let you go? A better comparison is several back-to-back 1/4 mile runs, although this only measures one element (straight line acceleration) of a car, not its cornering ability, etc I suppose you could get into timed laps of a racetrack, but then at trackdays you're not allowed to time laps, and there's other traffic etc. hence why the 1/4 mile run what you brung is the best opportunity.

On what factual basis can you claim that k-jet is garbage ?
It is an amazing piece of engineering that is simple and if looked after will give excellent service and performance for years and years.

lhasadreams said

On what factual basis can you claim that k-jet is garbage ?
It is an amazing piece of engineering that is simple and if looked after will give excellent service and performance for years and years.

Unfortunately Brutal didn't do a before-after comparison, and in any case its an engine conversion, not just swapping the injection to carbs. I've searched the internet for reliable before and after dyno runs for someone 'upgrading' to twin carbs, unfortunately people tend not to post the results - maybe because they're disappointed with the figures?

If Brutal has a rolling road figure of 90bhp for a KR with head work, it illustrates something's not quite right with the setup. Whether this is just that it needs tuning; or something more fundamental with the choice of using carbs - you'd need to do before and after comparisons.

lhasadreams said

On what factual basis can you claim that k-jet is garbage ?
It is an amazing piece of engineering that is simple and if looked after will give excellent service and performance for years and years.

His m8 said……  :dontknow:

Come on put up the results!!!!

Backed up by a scan of the rr sheet!!!!

Or is it a case of my car is 40000 bhp because i brought a £5 chip from ebay lmao