And so it begins

[casey]

Hey I haven't read what previously been said but all that work your doing is great different but when u can get pressure into the cylinders with a turbo your engine running with a charger u actually gotta have power to make power and even u loose power when stuffing around with chargers especially on a incredible small hp engine all the negatives that a turbo might have still will overcome the benefits of a charger like 3 cylinder motors are terrible when comes t power and weight just think of it this way the crank would almost weight as much or even the same as most v6 cranks even though it have more cylinders it makes up for that by power to weight is better so what I'm saying if u were to go with a 3 cylinder wouldn't all the power most likely be gained from the head like twin overhead cam head work turbod n intake injectors computer ect to gain more power?

[mini_kompressor]

Im going to have to disagree here with casey, sorry. This misconception that going turbo over supercharging all because its a 3 cyl, low power engine , is quite plainly bulls t. Anyone who has seen, or been ( you know what i mean HUSKY ) in my own Mb will know that itll keep up with any of the turbo mb's out there, without any low down lag, and without any major powerloss from the driven "supercharger". The quickest road registed mb here in Vic, which id have to say is Gavins Mb, has a swift gearbox in it, and in most "runs" weve had i can keep up with him until he slips into "5th" gear. Now this is a car running F6A DOHC, fuel injection, turbo, etc, and im running an F8B SOHC, carby, supercharged with 8psi boost. Never have i ever really felt that there has been a massive disadvantage to going the Supercharged route. Keep plugging with the idea Trav
Oh, my mate cant do custom manifolds at present, his alloy welder has closed doors. Sorry about that, sure youll think up something else.

[Trav]

Mini-kompressor, thanks for asking your friend about the manifold. It was starting to get a little to hard going down that route, so I've made the big decision and am going the EFI route. I'm now looking at mounting the supercharger down where the alternator is and plumbing it over the engine to an F6A EFI intake as a blow-through setup. This will be a bit neater than mounting it on the other side of the engine and trying to twist the plumbing up to fit. Plus, if I want to add an intercooler later, it will be a lot easier.

[casey]

To mine even thou it's not reg doesn't make an difference t power but it's twin over head cam naturally aspirated no head work put out about 43kw at the wheels of mine lighter engine less weight has heaps power down low enough that it has snap boost for down low and top end it's all about the combination, I race and win around the track bec I have a successful combination many combinations I still am working on right now but when the overall 2nd engine is finished in any street reg mighty boy will be easily tuned over 100kw like if I wanted t go further more money but still it all come down to preference and any one I'm linked with an ask advice on tells me the turbos a winner for such a set up

[supervan]

i would rather blow then suck


blown = no lag

turbo = lag

plus you should make more torque with a supercharger

and remember hp sells torque wins races

[Husky]

Im going to have to disagree here with casey, sorry. This misconception that going turbo over supercharging all because its a 3 cyl, low power engine , is quite plainly bulls t. Anyone who has seen, or been ( you know what i mean HUSKY ) in my own Mb will know that itll keep up with any of the turbo mb's out there, without any low down lag, and without any major powerloss from the driven "supercharger". The quickest road registed mb here in Vic, which id have to say is Gavins Mb, has a swift gearbox in it, and in most "runs" weve had i can keep up with him until he slips into "5th" gear. Now this is a car running F6A DOHC, fuel injection, turbo, etc, and im running an F8B SOHC, carby, supercharged with 8psi boost. Never have i ever really felt that there has been a massive disadvantage to going the Supercharged route. Keep plugging with the idea Trav
Oh, my mate cant do custom manifolds at present, his alloy welder has closed doors. Sorry about that, sure youll think up something else.

I would have to agree! Its fantastic and keeps pulling... mini kompressor's car is FAST . All things being equal weight wise drivers/cars I reckon it might be even a touch quicker than Gavin's Both cars are awesome and I enjoyed the ride in both and am very thankful for the experience
Cheers

[Brayden]

I think the argument against superchargers on small engines is largely fought by people who have tried to use a charger that is too big. An AMR300/500 puts very little drag on a motor and it doesn't have to deliver high CFM, so it doesn't rob much power in order to make decent gains. End of the day though any supercharger will take power to make power.
However a similar argument could be made against using turbos on a small motor because of lag. It is all relative to what size the turbo or supercharger as to how it performs.

I'd like to line up the snot rocket against Ben's supercharged F8B SOHC and see how it compares to a turbocharged F8B SOHC. I think it would be a very interesting (and close) match, and I really don't give a stuff who wins!

Comparing Ben's car to Gavin's is difficult, as the F6A DOHC produces results up high, whereas an F8B (turbo or super) has grunt down low from the longer stroke and extra 150cc.

[casey]

I'll have to show u my torque when the motor is finished when it has been dyno tunned I'll actually show u the bit of paper! But I don't know what combinations of turbos others have been using but I'll Guarante the right turbo combination u will have no or no lag proven just like the evos no lag unless your in the wrong gear just like mine. Just can't afford to loose that little power the naturally aspirated 3cyl has got!

[supervan]

put your foot down in a blown application and there is instant boost

put your foot down in a turbo set up and there is lag untill revs build and then boost builds pound by pound

so what im saying is that if both set ups are runing say 10psi the blown set up will be producing 10psi from about 1500rpm or pretty much as soon as you put your foot down and holds to redline. where the turbo set up will produce full boost from about 2800-3000rpm to redline so the blown set up will have say around 4000rpm worth of boost where the turbo will have say 2500-3000rpm worth of boost. a blown f8b sohc vs a turbo f8b sohc would be a great race i think the blown mb would jump the turbo set up of the line but the turbo will have a bit more up top... also to turn a amr 300/500 would take sweet phuck all

[Brayden]

I don't want to shoot down your theory, but my F8B produces boost from about 1900RPM and full boost by 2300. Heck it will even produce 7PSI when free revving! As I said it does come down to selecting the right size for your application.

[mini_kompressor]

I accept the challenge Brayden , i reckon next year in Albury we line up again on the Hume, 2nd gear rolling start . Im like you, dont care who wins, but i reckon it would be close

[casey]

http://tomak3.tripod.com/page10.html
Have a read this then race me my targeted full boost be at 2500 and that's what I'm getting any more boost at that low rpm will stress my lilttle motor t bits your lil engine lol would not be giving it 10 at 1500 lol, your lil engine needs that to turn it with your lil engines little cars little power and BIG strip and long circuits I'm sure I'll be in front with no wheel spin from the start to finish I can remain on a good steady boost from a standing start with out wheel spin and retain then gain from the point GO

[nelpd96]

Mate, that link that you provided is talking about centrifugal compressor. We are talking about positive displacement vs. centrifugal. What people need to understand is that the mechanism for each is very different. A positive displacement supercharger moves a fixed amount of air for each revolution. In the case of the AMR500 it is 500cc per revolution. How much "boost" that creates is a function of gearing, engine size and efficency. Say we have it fitted to an F8 that have a VE of 75%. If we run the blower at 1:1 ratio then we can expect boost of around 9.8 psi. If we change the VE of the engine by fitting a cam and extractors and the VE increases to 85% then boost will drop to 6.8psi. The vital thing to remember here is that the airflow remains the same so when it comes to positive displacement superchargers we need to look at flow not boost. A positive displacement supercharger just makes the engine feel bigger ie. Using the example above that F8 would have similar characteristics to a SOHC 1.2lt engine looking at the flow requirements.

The turbo on the other hand is exactly as most people say, it physically compresses the air inside the turbo housing to allow more air in the same volume. The energy to do this is found through the pressure differental across the exhaust housing. To get the engine to boost early you have to make best use of this. A 3 cly engine is not as good as a 4 cly for this due to the seperation of the exhaust pulses but nothing is insurmountable. Certainly a well designed exhaust manifold that would keep the exhaust gas velocity up would help. Where turbos win out is that air flow is not linked to the displacement of the engine directly, rather the gas flow charateristics from the exhaust and the compressor maps. The use of small exahust housings and external gates to reduce back pressure higher in the rev range should net very good boost response without the need to sacrifice top end.

At the end of the day it is kind of academic because these things were never made to be race cars. If you are chasing high power to weight numbers then a Swift GTI is a much better start point. Even my Sprinter would have a better power to weight than most if not all cars on here.

Paul

[casey]

Doesn't change that it's a BELT driven charger still robs power from the crank it did mention the centrifugal type but it's not just talking about the centrifugal type it talks about superchargers in general The engine will still needs to turn this charger to eventually But not instantaneously not with there lil engines, just have another look at my video with my old engine no boost drop no lag
http://www.google.com.au/search?q=Suzuk ... ent=safari. It's the first video. Just curious what's your power to weight ration u have in your Sprinter and hp?

[nelpd96]

You are right it does take power to run a supercharger, it also takes power to turn the exhaust housing on a turbo. Regardless of the method of compressing the air it will still take a certain amount of energy. Assuming 100% efficiency that energy will be the same regardless of the method. The benefit of the turbo is when properly matched it will be able to create a greater pressure ratio for a given efficency. If you try and run high pressure ratios on a positive displacement supercharger the rpm needs to increase and efficiency drops off.

As for the sprinter it is probably putting out about 160kw with the T25 that I have on it but I have not been back to the dyno since the engine rebuild. I am in Townsville so if you want to have a look let me know.

Paul

P.S. I don't think that anyone is doubting your car, it is just as a Mechanical engineer with plenty of experience there are some fundamentals of thermodynamics that just can't be ignored.