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3594 Posts Member #: 655 Post Whore Northern Ireland |
3rd Feb, 2007 at 06:57:14pm
On 3rd of Feb, 2007 at 06:43pm Axel said:
Given the above, I think chaising power from revs lacks rewards. I would agree. I see little reason, why silly power cannot be achieved with a redline of 8000rpm, and still have good road manners. Although one small benefit of using rpm's, is the torque is reduced, which can help with box/clutch issues. Mine used the very tame SW5, and had a very very useable 7500rpm on tap. Decent exhaust manifold, proper turbo selection, and good cylinder head along with a sensible cam, will all lead in the right direction. If we dont like big cams, as I dont.....whats the score with going nuts on valve lift on an A-series ? Only ask, after seeing a set of 1.7's on ebay Edited by stevieturbo on 3rd Feb, 2007. 9.85 @ 145mph
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 2909 Posts Member #: 83 Post Whore Glasgow, Scotland |
3rd Feb, 2007 at 07:10:18pm
heres a little practical info i gathered the other nite when dure to an unfortunate chain of events i only had 2 cylinders working.
turbo 16v k-series 11.9@118.9 :)
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3594 Posts Member #: 655 Post Whore Northern Ireland |
3rd Feb, 2007 at 07:22:28pm
On 3rd of Feb, 2007 at 07:10pm evolotion said:
heres a little practical info i gathered the other nite when dure to an unfortunate chain of events i only had 2 cylinders working. me engine is a 1400cc 16v lump which breathes into a T25 turbo from a S13 200sx. a pretty small turbo when big power is needed. anyways she had no boost untill 5000rpm, so god help you if you had a more athsmatic engine of smaller capacity. Poor turbo selection then..... Mine was a Cossie 4x4 Compressor, on a 0.36 T3 Turbine, and it made full boost by 4500rpm then pulled very hard until over 7000rpm, with decent torque available from a little over 3000rpm when boost started to build.. ALthough it was very torquey for what it was everywhere off boost. Yes, it did take a while to spool up, but never that big a deal for me. Just imagine how old and crappy that turbo design is !!!! Then imagine what a proper ball bearing unti will be capable of. Surprising you had such poor results on your engine. 9.85 @ 145mph
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 8604 Posts Member #: 573 Formerly Axel Podland |
3rd Feb, 2007 at 07:22:46pm
On 3rd of Feb, 2007 at 06:57pm stevieturbo said:
If we dont like big cams, as I dont.....whats the score with going nuts on valve lift on an A-series ? Cams is one big area that we have not got any agreement on what works and what doesn't. If we find one that works we keep it a secret 
Interesting that you got the SW5 up to 7500rpm. It supports my theory that you do not need long duration/overlap with a turbo. High lift has got to be good though, but 1.7s are a bit extreme, in my opinion. My secret special grind cam has 0.380 lift on standard rockers. I dont think anymore is going to be beneficial. Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
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2909 Posts Member #: 83 Post Whore Glasgow, Scotland |
3rd Feb, 2007 at 07:32:26pm
stevie, that was runnig on only 2 cylinders, jstu throwing it in as it responded as a twin turbo setup would on a 4 cylinder engine. assumign same engien and turbo's
turbo 16v k-series 11.9@118.9 :)
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3594 Posts Member #: 655 Post Whore Northern Ireland |
3rd Feb, 2007 at 07:52:49pm
On 3rd of Feb, 2007 at 07:32pm evolotion said:
stevie, that was runnig on only 2 cylinders, jstu throwing it in as it responded as a twin turbo setup would on a 4 cylinder engine. assumign same engien and turbo's running on all 4 cylinders i have 20psi @3200 rpm :) WTF where ya doin running it on 2 cyls lol !!!! But you do prove my point, that a biggish turbo, can, and will be very effective on a small engine Axel... There are a lot of variables. I wouldnt think, EGBP would also play a massive part on rpm ability. If a small turbine is choking the engine, then high rpm's will always be harder. Add to that a small compressor, lacking puff.... Going for a bigger turbo, which may take a bit longer to spool, will still allow you to use that mild cam, and still pull hard up top. I could pull 7500rpm in 4th, so even if it was tailing off a little after 7000, there was still plenty of power there. Mapped ignition, and nice AFR's could only help further, especially at the lower rpm's I never was able to get much over 1.5 bar though. Even with an 18psi actuator, I couldnt get more boost. Not sure why, but never did look into it further, as I was reasonably happy with that boost. The bleed valves I were using were pretty crap though, with a very small bleed orifice, so maybe a proper boost control setup would have been better. I was just using green plastic fish tank jobbies from PetWorld  . £1.10 for 2
Either way, more boost should have been easy. Unless due to EGBP, or the compressor wasnt suitable or capable. But given the Compressors origins, it should have been more than capable. A guy in Malta is using a std Cossie turbo on a Starlet, and trapping 120+mph, and very low 12's ( think he actually said he done 11.9 ) Its only a 1300cc engine, albeit a more efficient one. 9.85 @ 145mph
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3594 Posts Member #: 655 Post Whore Northern Ireland |
3rd Feb, 2007 at 08:04:16pm
On 3rd of Feb, 2007 at 07:32pm evolotion said:
stevie, that was runnig on only 2 cylinders, jstu throwing it in as it responded as a twin turbo setup would on a 4 cylinder engine. assumign same engien and turbo's running on all 4 cylinders i have 20psi @3200 rpm :) WTF where ya doin running it on 2 cyls lol !!!! But you do prove my point, that a biggish turbo, can, and will be very effective on a small engine Axel... There are a lot of variables. I wouldnt think, EGBP would also play a massive part on rpm ability. If a small turbine is choking the engine, then high rpm's will always be harder. Add to that a small compressor, lacking puff.... Going for a bigger turbo, which may take a bit longer to spool, will still allow you to use that mild cam, and still pull hard up top. I could pull 7500rpm in 4th, so even if it was tailing off a little after 7000, there was still plenty of power there. Mapped ignition, and nice AFR's could only help further, especially at the lower rpm's I never was able to get much over 1.5 bar though. Even with an 18psi actuator, I couldnt get more boost. Not sure why, but never did look into it further, as I was reasonably happy with that boost. The bleed valves I were using were pretty crap though, with a very small bleed orifice, so maybe a proper boost control setup would have been better. I was just using green plastic fish tank jobbies from PetWorld . £1.10 for 2
Either way, more boost should have been easy. Unless due to EGBP, or the compressor wasnt suitable or capable. But given the Compressors origins, it should have been more than capable. A guy in Malta is using a std Cossie turbo on a Starlet, and trapping 120+mph, and very low 12's ( think he actually said he done 11.9 ) Its only a 1300cc engine, albeit a more efficient one. 9.85 @ 145mph
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8604 Posts Member #: 573 Formerly Axel Podland |
3rd Feb, 2007 at 08:21:24pm
Stevie,
Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
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3594 Posts Member #: 655 Post Whore Northern Ireland |
3rd Feb, 2007 at 09:29:02pm
On 3rd of Feb, 2007 at 08:21pm Axel said:
Stevie, I have no practical experience of running turbos, so I'm firing in the dark. But, did you not consider that the problem was probably the 0.36 turbine? I'm guessing but if the compressor should have provide the boost based on the map, the only thing missing is the power to drive it fast enough. The power to drive a centrifugal device goes up by the cube of the speed, to double the speed of the compresor, the turbine has to give 8 times the power. Turbine power output is determined by the pressure drop across the nozzle. Past a certain point a lot of pressure drop gives very little gain in power due to a drop in efficiency of the nozzle. Even with the wastegate closed, you couldn't get the boost if the turbine nozzle couldn't flow the gas. Bare in mind, my Mini was mostly around 1994-1996, with some changes circa late 1997 or so ( SW5 and new head ) Turbo knowledge, and technology has moved on quite a bit since then, and more importantly, my own knowledge. At that time, I requested a turbo from Turbo Dynamics, and that is what they built for me. Although it did undergo a few rebuilds during its life, for a variety of reasons. I never did try to see what boost it would make, with the w/g shut. While I wanted more boost, it was my daily driver, so I couldnt get too greedy, as even then I knew all to well what that does. The 0.36 turbine should have been ok, and was run in conjunction with a clipped wheel. generally if the turbine housing is too small, boost will climb un-controllably. I never had that problem. unless of course it was so restrictive, the engine was choking itself. It was also on a standard cast elbow and 2" downpipe, so maybe those things werent helping too. I really think that one of the Nissan GT28 units would be good to try on a Mini. 9.85 @ 145mph
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 6752 Posts Member #: 828 Post Whore uranus |
4th Feb, 2007 at 11:43:07am
steve , if your bleed valve was way open , and there was no increae in boost ,then try shoving a .25 or .5 mm jet in the pipe from the boost takeoff that goes to yuor valve , that should make a big diff , so turn the valve right down and open gradually so yuo dont bend the needle on the boost guage.
Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM |
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3594 Posts Member #: 655 Post Whore Northern Ireland |
4th Feb, 2007 at 02:24:46pm
On 4th of Feb, 2007 at 11:43am robert said:
steve , if your bleed valve was way open , and there was no increae in boost ,then try shoving a .25 or .5 mm jet in the pipe from the boost takeoff that goes to yuor valve , that should make a big diff , so turn the valve right down and open gradually so yuo dont bend the needle on the boost guage. im suprised it took that high an rpm to start boosting ,was the cam in a bit retarded ? with the whole revs q , its a technical challenge for some to create the most torque or bhp ,out of such an old engine , and i think go for it .its all good clean fun ,and the only drawback is the occasional ventilation of the roof over the rolling rd bay !  oh axel ,that 16 psi per 100% power increase is poss true for the first 16 on a good engine poss more ,but once it gets into the higher boosts its unlikely to manifest , without some mega intercooling and turbo efficiency at those 25 to 35 psi areas .which is difficult ,(but not impossible) to achieve , :)
robert Robert, I know now about using a restrictor now, but I havent really driven the car in im sure 7+ years now, and even than very little over the last 9 years. But during 94- early 97 or so, it was driven daily. So its of little consequence, and the car, whilst it does still drive, is in no fit state to be driven legally, or safely to carry out any further testing.. The apparent "lag" was purely down to a relatively large blower, but once on boost, it did perform well. As I say, a modern BB T3 unit, would probably spool a lot earlier, and produce even better results, or the GT28 unit as I suggested. Where the bigger units would shine, is at the higher boost levels too. Better exhaust and inlet systems would also have helped too. Intercooling isnt a problem, you can alwys squeeze something big enough somewhere, or just squirt a little water or methanol to assist cooling. These can offer huge benefits. As an example on my own Granada, Sometimes temperatures at the track, have reached as high as 70degC largely due to heat soak when queueing. When I added the methanol injection, intake temp may be reading circa 50degC before a run. As soon as the meth goes in, it almost immediately drops to circa 20degC....and stays there for the duration of the run. The cooling effect is excellent....as well as the added octane boost methanol gives. Ive never tested water along on my car, moslty just 90%+ meth /water Its something that is very under-used here in the UK. Some say water is best, some say 50/50, and others say 100% meth is the way to go. next time around, my mini will be much much improved, and I will be starting work in it this year. Doubt it will be going this year though. 9.85 @ 145mph
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6752 Posts Member #: 828 Post Whore uranus |
4th Feb, 2007 at 02:49:56pm
yes i agree steve the whole water thing is not embraced much .
Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM |
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591 Posts Member #: 360 Stu from Corwall aka Mr Jazz Piano, Love_Machine, kneegrow |
8th Feb, 2007 at 08:53:25pm
I've wondered about blown cars and blowing through the turbo with a suck-open valve between the blower and the turbo compressor. So, you nail it at low revs, the blower sucks through the flap and then the turbo spools up, the flap closes, the pressure diff across the blower drops and so does the 30hp or so it requires to make about 14psi at 6000 rpm. So, everyone's a winner.
Bugger off, I'm getting there. |
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617 Posts Member #: 6558 Post Whore Pueblo, Colorado, USA |
15th Jun, 2010 at 07:55:21pm
Alright, dredging this up from the depths. Would it not be possible to twin turbo with a gt15 or gt17 for low down boost and a gt28 for higher up, try to keep boost through the whole range? Or in the case of a small bore, a gt15 and a gt22 or gt25 for the upper end? |
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6752 Posts Member #: 828 Post Whore uranus |
15th Jun, 2010 at 08:26:32pm
yes ! Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM |
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8604 Posts Member #: 573 Formerly Axel Podland |
15th Jun, 2010 at 08:47:06pm
But no point as you can always get boost in the useable rev range from a correctly sized turbo, even with a 4 speed box. Just getting on boost in 1st is an issue. Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
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617 Posts Member #: 6558 Post Whore Pueblo, Colorado, USA |
15th Jun, 2010 at 09:28:59pm
So how about on an 850? I think too big a turbo would be a huge problem. I think it was Will h(correct me if I'm wrong), that said a gt17 would be best for a 998, maybe a smaller gt15 for a 850. But I'm looking for long amounts of boost. I was contemplating a gt12 and gt17 combo, small charger for super low down boost that's staged to go to the gt17. Possibly giving boost as early as 2500rpms... Not sure, still researching the usable end of it all... |
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520 Posts Member #: 2093 Post Whore Grenoble, France |
15th Jun, 2010 at 10:41:59pm
The problem with a small turbo working at high revs is a properly designed exhaust and WG in such a small space we have in the Mini.
std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm |
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617 Posts Member #: 6558 Post Whore Pueblo, Colorado, USA |
15th Jun, 2010 at 11:00:11pm
I can see it being a problem, hence the reason I'm relocating the rad to the front free up that wing, with electric water pump, so I could fit a turbo over there, and I could then do a turbo over the clutch housing... |
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6752 Posts Member #: 828 Post Whore uranus |
16th Jun, 2010 at 07:24:46am
do it . Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM |
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4314 Posts Member #: 700 Formerly British Open Classic The West Country |
16th Jun, 2010 at 08:28:46am
Isambard Kingdom Brunel said:
Nothing is impossible if you are an Engineer |
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 9502 Posts Member #: 1023 Post Whore Doncaster, South Yorkshire |
16th Jun, 2010 at 12:38:34pm
how did i miss that thread? Yes i moved to the darkside |
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617 Posts Member #: 6558 Post Whore Pueblo, Colorado, USA |
16th Jun, 2010 at 01:49:34pm
Lol, I dont' know, but that's exactly what I'm thinking!
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