paublo999
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| posted on 2/5/12 at 10:20 PM |
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Rotrex bec owners?
Any bec/rotrex owners out there? Looking to compare setups and performance levels.
Cheers
Paul
My videos http://www.youtube.com/user/ninjabogeyracing
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athoirs
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| posted on 3/5/12 at 10:43 AM |
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Wot's wrong Paul????
Not fast enough???
(Looked bloody fast enough at Kames the other week!!) 
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paublo999
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| posted on 3/5/12 at 10:47 AM |
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Nothing wrong, more a discussion around boost v pulley sizes, intake temperatures etc
Looking for a clean run at Fintray and to smash some records  i will have the new camera running by then do watch this space.
My videos http://www.youtube.com/user/ninjabogeyracing
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athoirs
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| posted on 3/5/12 at 11:02 AM |
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Good luck at Fintray - not going to make it myself 
See you at Kames??
Andy
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paublo999
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| posted on 3/5/12 at 11:05 AM |
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I'm planning to be there
You focusing on sprints or just as your diary allows?
My videos http://www.youtube.com/user/ninjabogeyracing
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athoirs
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| posted on 3/5/12 at 11:46 AM |
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Two W's
Work and Wife!!
and doing the Lowland - just less travel costs
Andy
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kjouk
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| posted on 3/5/12 at 12:01 PM |
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Maybe worth having a chat with Nick or Luke Algar at Playskool Motorsport. Nick used to run a supercharged busa in one of his sprint Westfields, they
do rotrex install work as well.
I have a lot of data from a turbo busa if thats of interest re: inlet temps etc.
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PAUL FISHER
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| posted on 3/5/12 at 12:03 PM |
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I think Paul Nightingale at Spire sportscars had a zzr1400 supercharged demo car at one point, don't know if they still have it, but could be
worth giving him a call on what set up he ran.
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paublo999
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| posted on 3/5/12 at 12:27 PM |
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Cheers guys
Nick and Luke done a whole load of the work for me and done a sterling job. My efforts are to see if there are other rotrex users out there is to
compare and contrast.
My setup is creating 10.5 lbs of boost with a 82/80mm pulley config. Just wondering how others have got on. I know Toniq has one on his busa and I
hope he will reply.
My logger ain't installed yet and I have just wrapped the intake system and was wondering about the impact on performance of intake temps etc.
I have nothing specifically wrong, just my ongoing desire to learn and optimise.
The car shows great potential
Cheers
Paul
My videos http://www.youtube.com/user/ninjabogeyracing
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kjouk
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| posted on 3/5/12 at 01:10 PM |
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Ah.
Some rough figures that might be useful. 10psi should equate to ~80C inlet, with decent intercooling that might get down to ~35C with 40bhp power
gain. These are steady state figures, for hills/sprints the numbers tend to be better as the intercooler/pipework will absorb heat first so its only
longer runs, double lappers etc where the temps get high. For those you may need to make air temp fuel compensation to stop it going too rich if you
are not already.
My turbo max is 18psi, at this level you have quite some issue with the throttle being non-linear, most of the boost (assuming the turbo is fully
spooled) arrives in the 20%-40% range which is difficult to handle. At 7psi you can hardly feel this effect at all. I have not driven a rotrex BEC
but I would imagine it would have somewhat similar characteristics although perhaps a bit softer due to rev control over the boost.
I am running various "control strategies" to try and manage the onset of higher boost, can't say its been that successful yet. On
paper (datalog based simulations etc) it should be breaking records, in reality its not been reliable enough or had the right setup on any given day,
yet...
Kev
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paublo999
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| posted on 3/5/12 at 06:14 PM |
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I have a pretty large intercooler but have yet to get any decent data on temps yet. I did notice some heat soaking into the intake system from the
exhaust on the intake pipe so have wrapped it with heat reflective cloth.
On the dyno 10.5psi has equated to a healthy increase of 70+ horsepower and 30lbs/ft torque. The rotrex is boost limited to just under 1bar but
unlikely to create anything like that with intercooler etc. The power delivery is smooth and while not as much boost as a turbo I believe my decision
to go supercharger has been the right one. 250+ bhp at the rear wheels can spin up 9.2" soft slicks without must resistance. First time out with
a poor gear change setup I went within a second of my best run at Kames on my second practice. Unfortunately a little engine issue stopped play but
hope to remedy that at Fintray on the 12th. Many of the turbo guys struggle to control overboost so hopefully a much simpler vacuum bov will be fine.
Have you considered any extra cooling such as charge or co2 type setups. My runs are from 28 to 80 seconds plus warmup. I have kept the car road legal
but only do a few setup miles and don't bother with track days anymore.
My injectors are maxed and I have a few more upgrades but these will have to wait until later in the year
Big thanks must go to Playskool and Daytuner for their services
My videos http://www.youtube.com/user/ninjabogeyracing
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kjouk
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| posted on 3/5/12 at 09:30 PM |
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On temps I wanted to go intercooler as car is double driven and that would mean carrying a lot of water (and weight) for a charge cooler to keep in
check. With ducted intercooler see air temps rise from 30C to 70C over a 100sec run at Anglesey.
I have now setup for adding a small barrel charge cooler just for longer tracks. Have not tested this yet but made a few mods over winter that appear
to have improved cooling significantly to the point where I am not sure the charge cooler will be needed. The changes were mainly to the engine bay,
moving dry sump and floor parts. Think the improvements are all to do with lower pressure behind the intercooler as water temps have also fallen a lot
but hard to be sure.
I have heard that water/meths can be very effective but not got any real data. I have avoided because water injection reduces power and water/meth
changes fuel needs. Good for protecting the engine but not my first choice.
Sounds like you are on a good path though once you have some logging in place you can play some more. Most of the turbo/supercharge debate is rubbish,
from what I have learnt its all about boost levels and how you control the throttle if you up the boost to far. Good move staying road legal, I bought
mine like that but took it off road too early which makes testing a pain. Very difficult to run on trackdays now without getting very frustrated.
Sure best advise is not get greedy on power (I still am), get it reliable and then start shedding the weight. My car is now ~75kgs lighter than when I
got it, makes a big difference and makes the car simpler to maintain as well.
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paublo999
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| posted on 3/5/12 at 09:39 PM |
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Wise words
I haven't cut the holes in the bonnet yet to let the air escape but have been talking about it for some time.
I have calibrated the race tech 2 dash now do hopefully more meaningful figures will be displayed. I have also borrowed a pyrometer to check things
over the weekend.
The concept of an intercooler co2 spray system is interesting. The concept of blasting the intercooler before you launch to get super chilled air? For
sprint and hill runs the co2 could be detachable and only have the weight of a short airline and copper hose.
Will post back on progress.
Cheers
Paul
My videos http://www.youtube.com/user/ninjabogeyracing
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kjouk
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| posted on 5/5/12 at 09:53 AM |
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Hi Paul,
Hope it goes well for you. I wasn't sure about the CO2 route, maybe it will work but I don't really want anymore power at the start of a
run, a bit extra at the end maybe. Be interested to see how you get on.
I have explained what causes me grief to a few people but thought it was time I wrote it up a bit better so you might want to have a read of
http://wp.me/p1J3f-56.
Kev
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paublo999
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| posted on 5/5/12 at 10:41 AM |
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Hi
We have had three turbo sprint/hill cars in Scotland and none of them have been reliable or really show their potential. All seem to over boost or not
be that driveable. I enjoyed your write up but can't help thinking that 300bhp at the crank on a seven is plenty? You could dual down the boost
and then increase as you improve te car? I have gone pretty quickly with 200ish but have yet to see the difference in times. My main adversary last
year was a twin charged evo 5 with 800+ bhp. I only beat Donald the once but was always close. Hence a little bit more power to even things out a
little
On my limited miles with the rotrex I didn't find it any harder to drive and after couple of laps was starting to use the power. My issue like
you is that I am not the type of person to settle for x power and am always looking to tweak that little bit more
My success criteria for the project was to be able to scare myself. Even after the short drive I think there is no chance of that and therefore should
have considered a a 500bhp turbo but I am yet to see one that works apart from Mr Cowper I hope you get the car the way you want it. Keep me
updated
Timesheets can do the talking during the year and can decide if I have enough and have done the right thing
My videos http://www.youtube.com/user/ninjabogeyracing
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kjouk
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| posted on 6/5/12 at 07:17 PM |
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The sensible thing would be to dial it down but I think I might just mask the issue rather than resolve it so not so keen to compromise although I
probably should. Over 300bhp is a lot, but that's the norm with <500kg for the class I run in. Duncan is about on par with the leaders from
the few results I have seen.
On times I found gains really start to come at higher speeds where you can use the bhp to overcome aero, in a drag race between my road-legal R1 and
the busa you don't see much difference <75mph, but the busa will make it to 120 nearly 8 seconds quicker, shocking what a bit of head wind
will do and I never really cottoned on to this until I started comparing the logs.
Sure you have made a good choice. On a fun/£ basis hard to beat boosted BEC, just be wary of what kind of problems might crop up if you get greedy
like me.
Kev
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paublo999
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| posted on 7/5/12 at 10:39 PM |
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Jut got some feedback from another forum saying that I should be seeing 16 psi with the pulley ratios I am running.
Either belt slip or an inefficient intercooler appear to be the top suggestions. I need to get another map sensor and measure the boost pre
intercooler.
Any suggestions in what car to get one off of. Was looking at 2.5 bar vw units as they are cheap and plentiful. Any better suggestions without
spending £80+ on one from Race Technology.
To respond to your thread. Duncans car on ten if the best is bery impressive. My highest recorded speed in Scotland is 95mph so most of my running is
less affected by the aero efficiency. Probably should go on a diet and really attack the car and loose some weight. Car is currently around 490 with a
few litres in it. Too heavy
My videos http://www.youtube.com/user/ninjabogeyracing
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kjouk
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| posted on 8/5/12 at 08:28 AM |
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I use a couple of the 'GM' 3-bar sensors. Usually buy from efi-parts but could not find it there this time, this Ford
Cosworth 3 bar Manifold Air Intake Pressure / MAP Sensor | eBay looks identical. You can get the calibration figures from the DTA software or I
can email them.
Find it hard to believe your are loosing ~5psi over an intercooler, mine looses ~1psi. You might also have a leak. I ended up running pressure tests
on mine by blocking up various parts and seeing if it they would hold 20psi. Found one large one, in the intercooler and a few smaller ones, mainly in
ali welds which surprised me. Don't know much about slipping issues.
That's a bit smaller weight to where I started from, lost ~35kgs going non-road legal but that included ditching some 17" wheels to get to
~475kg, over winter lost another ~35kg with a full rebuild. Don't think there is much more to go at ~440kg, not without spending a lot on CF.
The lightest 1L westfields are getting down to ~400kg, Think the difference is just turbo (15kg), intercooler (5kg), air plumbing, plenum & bov
(5kg) & engine (15kg).
Kev
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paublo999
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| posted on 8/5/12 at 02:14 PM |
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Looking like a leak from what I can determine. Cant see any belt slip from the dyno videos. Will run round the jubilee clips tonight and have to tweak
the gearchange so that will be me before Fintray.
Any easy ways to do a leak test or did you test all the components individually? Will order one of those sensors, thanks for the link
Paul
My videos http://www.youtube.com/user/ninjabogeyracing
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kjouk
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| posted on 8/5/12 at 02:43 PM |
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Think I did most leak testing on individual bits, depends on what is convient to look at. My kit for this was really basic, some ply discs cut to
various silicon pipe diameters with a hole in center to take tyre valves. Stick cheap electric tyre pump on one side, wait for pressure to build to
level and then watch to see if it holds. For plenum think I could not block that off easily so just put as much air in as possible and scouted for
leaks by noise.
Let us know how you get on at Fintray, I will be sat on the sidelines at Harewood wishing I was driving 
Kev
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paublo999
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| posted on 11/5/12 at 10:08 PM |
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Fintray cancelled, but now attending a test session at Kames on Sunday.
On the boost front, spoke to (a very helpful) Richard at TTS and he thinks it is more like belt slip. I have a certain amount of "belt
dust" just from the dyno and limited mileage, so considering using a longer belt and repositioning the tensioner to increase belt wrap. All
interesting stuff.
Have begun sourcing bits and pieces for the leak testing. It never ends
Will just be running old 888's at the weekend, but will try to get some video
My videos http://www.youtube.com/user/ninjabogeyracing
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