BMW K1200RS - Possible supercharger conversion
Turbo Mini Forums

is doune not this coming weekend?

Yes, but the closing date was before i even had a block so couldnt commit. Will be at Doune in the summer though.

Yes, i was a bit disappointed with 105 too tbh, however the setup was very much on the safe side of things and i'm hoping that it should be quite easy to double that figure without going too crazy with the boost

asctualy just sopotted the bit on the previous page about the boost compensation timing.... that expains the 105 hp, plenty more to come then!

also well worth playing with the valve timing, with the big cams i think a nice wide LCA will work, 112-114 deg,

I was wondering about cam timing actually. I used to run 2.4mm measured with a dti on the cam bucket when it was NA. I know alot of people use lt cams for turbo and the suggested lift for those is 2.0mm. I think I went for 2.3 when building it up but wasn't really sure of the logic involved. ..

How does the mm lift from tdc translate into degrees?

Lt normally 2.4mm, Rs normally 2.8mm lift on overlap. Every 0.1mm roughly equates to 1 degree. So LT's at 106 full lift or 2.4mm on overlap woul need knocking back to 1.8mm to be somewhere near 112 degrees at full lift

2.4 and 2.8 sorry yeah. Something to fiddle with when back on the rollers anyway

Slight update.

I managed to get the car on the rollers again and it made 171bhp at 1bar which was a little disappointing. It wouldnt make any more power at 1.1bar and intake temps began to climb. Also, back to back runs made it drop 10bhp almost straight away.

I then took it to the track and it felt great for the first 30seconds or so but began to feel nothing like the power it was making on the first lap. ( i do sprints of about 90seconds or so and 3 laps, so very short bursts). Came in and the intercooler was roasting hot, so im guessing i have a massive issue with charge temps. Really need to setup the data logging!

I was under the impression that others on here have pushed the gt17 much further than 1bar. Is that correct?

My intercooler (audi s3) is perhaps on the small side and although it gets a good amount of air, its not currently ducted very well, so the air is probably rushing around it, rahter than through it. Will experiment with ducting tomorrow to see if this improves anything. Also, there isnt a great amount of cool air getting to the inlet either, as the master clynders make this tricky (will probably have to source a different pedal box to sort this).


Next question, if this is the limit of the turbo, what are my options in terms of jumping up a size, do the bigger turbos like a gt22 or gt25 bolt straight onto this setup or is it more involved than that.

I want to be in the 200 - 250 range and i dont think im ever going to get anywhere near that with the current setup unless something is fundamentally wrong.

This is the current setup:

Intercooler sits behind the headlight opening:

yup fundamentally wrong lol

the intercooler needs to be as totally sealed to the headlight hole as possible .any air that can get around it ,will.

on my car i have run yp to 25 psi and its just pulling harder , it made 249 on the smart rollers at 21 psi , but they wre a bit iffy , i estimate around 250 at 6800 on 19 psi , and i think osme of the saab chaps have eked around 265 max out of the 17 .

also i think that compressor wheel is used on some of the chipped diesels at up to 35 psi .

completely seal that ic to the headlight hole and it will be a revolution .


edit to add ,also you may find a benefit from some much bigger breathers , i have a inch dia breather off the rocker box ,and two breathers off the timing cover and the drop gears casing .

Edited by robert on 14th May, 2016.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Thanks Robert. That's encouraging at least!
Issue is I remove the whole front very regularly so a complete seal I'd going to be tricky but will mock something up this morning and see if that has a positive impact on things.

If it makes a huge difference and I have to seal the gap's with tape fir each run then that's not too bad. Going to be a busy morning of cutting ally sheet and metal tape!

I had an issue with small breathers on a previous setup but this engine seems completely fine on this setup. No oil in catch tank etc. Any other symptoms to check?

oil temp? ,good thing is , if you do get a piston problem ,you will know all about it with such small breathers .instant diagnosis lol.

i can see what you mean about the front , maybe put the fan on the other side of the rad ,and move the ic down there ? maybe a much bigger one too ?

with ducting it has to be really strong ,there's a lot of force trying to get it to split open .

i always imagine it like a bucket ,with the ic as the base of the bucket ,and the sides as the ducting ,and you don't want ANY water to leak out of the bucket other than through the ic .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

What about adding WI if you can't get more efficiency from the intercooler ?

Phil.

WWW.TURBO-MINI.COM

I would say make a duct attached to the cooler that ends up just behind the rh headlamp and cut the headlamp out, I would think half inch gap between the duct and flipfront should be fine,

also dont make the mistake oof going too big on the duct inlet.... idealy you should be looking at approx 1/4 of the area of the core.

another good idea would be to get a hose from the turbo inlet out to some cooler air.

deffo rig up an IAT gauge if youve got concerns, or do some datalogs.

also how air tight is that plenum?

another option is to cut the grill full length and stuff a big cooler right across the front.

Duct made at track has made a huge difference to sustaining power for longer but it's still getting way too hot.

Plenum is an uknown quantity but the next thing to pressure test...

Water injection would great but I don't want more complications or the potential damage if it cocks up but probably need to do some reading up on that...

What's the logic in the intake being a quarter of the core? Will try and upload some pics of my temporary duct!

Good job for a lash up!

the basic idea is to match the flow area of the inlet of the duct to the flow area of the radiator, which is usually in the order of 25% of the core area, the duct should take the high speed air and slow it down so it can go through the core rather than just buffeting about.

http://glasairproject.com/GlasairI/AirSig/...ingSystems2.htm

That appears to be a very similar intercooler to the Audi TT one, definitely a good intercooler but perhapse you would benefit from something much bigger since you are looking at 200-250hp and have the K head.

Edited by robert on 15th May, 2016.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Could you make a little inlet to the compressor through the scuttle? It's a nice high pressure area to feed the turbo from.

In the 13's at last!.. Just

Also, WHERES THE FUCKING AIR FILTER!!

WWW.TURBO-MINI.COM

Regarding WI. If you don't tune the car to rely on it and simply add it to your current setup there shouldn't be an issue if the system fails.
The problem would be if you ran more boost/advance relying on the water injection and something went wrong with the system.
If your charge temps are as high as you fear, simply adding WI should see a decent reduction in ACT and a power gain.
Phil.

WWW.TURBO-MINI.COM

yes, its the same intercooler as a TT, as its from an S3, although the s3 has 2 of them. I had planned to fit 2 ( one behind each headlight) but it requires a fair bit of faff with pipework and too much pipework creates lag i believe. So i'm probably going to scrap that idea and fit a big alloy one. S3 has 225bhp, and i'll be hoping for around 200-250bhp yes.

I coudlnt get the data logging to work but i think its pretty obvious that charge temps are going through the roof. The car leaves the line with a very apparent 170bhp, and almost instantly feels like power starts to drop off, especially as the laps go on. By the end of the 3rd lap (total track time only 90seconds) its down 40bhp at least ( you can even hear there is far less air / turbo noises going on). The ducting did make a huge difference but its still nothing like what it should be. When i come in, the intercooler and plenum are very hot to the touch and when i plugged the laptop in a minute or so later, then air temp readout was 65degs ( this probably went up a bit since i stopped but cant confirm).

the scuttle is negative pressure on a mini i think, so probably wouldnt work for turbo inlet unless it was a naca duct or something like that.

The lack of air filter is an issue im aware of and it will have one next time im out, however the master cylinders only leave a few inches space, so didnt have many options and the manifold only when back on the car a few days before the event.

In light of all that, i think im going to make some pretty radical changes so that i can maximse the potential of this setup.

I do like the sound of WI and its probably ideal for the short sprints and hillclimbs. I'd be worried about it going wrong and hydrolocking.....

My possible plan:

New pedal box with internal master cylinders - seems like a lot of money and hassle to create a proper cold air feed but i dont see another option and it would create a lot of space to play with.


Alternator - because im only running for 90 seconds, and i think its ok with the regs. i could remove the alternator and mechanical water pump, remove that belt which would create alot of space, maybe a bit more power, plus the benefit of electric water pump to circulate water after i come in.


Rad / Intercooler - if i do the above, i can either move the radiator off the central location and fit a big square intercooler beside it, or move the radiator closer to the block, change the fan to a pull type and fit a large FMIC infront of the rad.

Next event is in a months time and pretty large changes (and expense!) like the above do introduce potentially reliability issues that i seem to have got under control for now but i think a combination of some of these needs to happen. My front slicks are also shot, so thats the best part of £500 to spend too!!

All you need to do is look at Jimster's and you can see that you can squeeze a huge rad and intercooler behind the clubman front.......

Were is your IAT sensor located
?