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Turbo GSXR
phelpsa - 7/8/05 at 06:59 PM

Would a TD04 turbo off a Subaru Impreza be about the right size for a GSXR 1100 engine? Subaru = 7000rpm 2000, GSXR 1100 = 11000rpm 1100cc. I've got a few ideas floating around in my head and there are quite a few of these turbos coming off imprezas.

Adam

evo3500 - 7/8/05 at 09:37 PM

Ive been having similar ideas of turboing my gt1 which is fitted with yamaha thunderace engine 1000cc,i was thinking more along the lines of metro tturbo unit small compact metro 1275cc so engine size not that different,although bike engine revs higher but i dont now the implications on the turbo for a higher revving engine but it would make a cheap home diy conversion.What do you think ?

phelpsa - 7/8/05 at 09:44 PM

I think you should get on with it

I know the GSXR internals are good for around 250-300bhp as standard, what are the thinderace bits like?

Adam

[Edited on 7-8-05 by phelpsa]

Noodle - 7/8/05 at 09:53 PM

quote:
Originally posted by evo3500
Ive been having similar ideas of turboing my gt1 which is fitted with yamaha thunderace engine 1000cc,i was thinking more along the lines of metro tturbo unit small compact metro 1275cc so engine size not that different,although bike engine revs higher but i dont now the implications on the turbo for a higher revving engine but it would make a cheap home diy conversion.What do you think ?


FWIW, in my youth David Vizard reckoned that the MG Metro was overturboed as it was essentially the same unit as fitted to the Lotus Turbo Esprit running at 220bhp, rather than the 93bhp of the MG.

Perhaps basing a sizing calculation on the Lotus rather than wheezy A+ is a better heuristic.

Cheers,

Neil.

phelpsa - 7/8/05 at 10:07 PM

I recon it would be safe to put 5 or 6 psi through the GSXR motor without lowering the compression. What do you guys think?

phelpsa - 7/8/05 at 10:35 PM

http://www.dragbike.com/forum/forum_posts.asp?TID=3172&PN=1

Useful link!

nanosleep - 8/8/05 at 03:04 AM

quote:
Originally posted by phelpsa
I recon it would be safe to put 5 or 6 psi through the GSXR motor without lowering the compression. What do you guys think?

I would say no to any boost on a unmodified bike engine. The performance bike engines have a compression ratio of near 12:1. You are already having trouble running 90-95 octane with this CR. On a small engine, it doesn't take much change in chamber volume to make a significant difference in CR. I did some calculations for my ZX-10R and determined I needed less than 1mm extra thickness on the head gasket to get the CR down below 9:1.
Post the bore, stroke, and CR for your engine and I'll do the math to figure if you can get by with a thick gasket. Does anyone know how much extra height the cam chains will allow?

For reference, I run 14lbs of intercooled boost on a 8.5CR cast iron V8 engine with 93 octane fuel. This is a fair starting place for figuring how much boost to run with how much compression. Others run the same engine at 20lbs but only with race fuel. The aluminum block bike engine should remove heat better and should be able to run a little more boost at the same CR. You can also play games with the engine tuning. More fuel, and more retard on the timing will allow more boost. Power goes up, efficiency goes down. IMHO if you plan on building an engine with boost, it's better to get the CR correct to start with.

For other reference, Ford racing produces a roots blower kit for the 98-03 Mustang GT. It provides a max of 6lbs of boost with no intercooler. The GT engine is 9:1 CR I believe. The same kit can be setup to provide 9lbs of boost (Ford calls this 'race only' so I assume it's using high octane fuel).

HTH
-Andy

garage19 - 8/8/05 at 10:13 AM

quote:
Originally posted by phelpsa
I recon it would be safe to put 5 or 6 psi through the GSXR motor without lowering the compression. What do you guys think?


Best to lower the CR a bit. Very easy on a GSXR have seperate barrels. Hust get a 1-2mm spacer lasered out to match your base gasket. Very easy if you know the stock cr of your engine to work back with a bit of maths and find out how thick the spacer needs to be.

I used to run 10 psi on my blade with 9.6:1

A mate runs 10 psi with 10:1 on an FZR1000 but he has water injection.

The good chamber design on most modern jap bikes helps limit det. Plus they have a lot of overlap on cams which lowers the dynamic CR.

Don't use the half engine size, twice engine speed theory as it doesn't work. I tried it on my first turbo bike and had trouble spooling up the turbo.

If you want a simple way of sizing a turbo with out all the maths and compressor maps, try to get the turbine from an engine that is slightly bigger and the compressor assembly from a car that makes the power you want.

If i was you with a 1100 i would go for a IHI turbo from an uno turbo and if i wanted over 200bhp add a larger compressor assemby.

phelpsa - 8/8/05 at 11:02 AM

Thanks for all the tips guys. I can run 99 ron petrol as the Tesco down the road sell it

I'll have a look around and see what turbos are around.

Bore x Stroke Size (cc) CR

78 x 59mm 1127 cc 10.0:1

I recon I could run a few psi because the engine is designed for 92-95 ron petrol and the CR is already quite low (for a pike engine).

Adam

[Edited on 8-8-05 by phelpsa]

scotlad - 8/8/05 at 02:07 PM

quote:

the CR is already quite low (for a pike engine).


wow motorised fish!!!! whatever next........

nanosleep - 8/8/05 at 07:00 PM

quote:
Originally posted by phelpsa
....
Bore x Stroke Size (cc) CR

78 x 59mm 1127 cc 10.0:1
....
[Edited on 8-8-05 by phelpsa]


Given the bore, stroke, and CR. I compute.
cylinder displacement = 281.92cc
cylinder large volume(piston down) = 313.24cc
cylinder small volume(piston up) = 31.32cc

I assume your head gasket shim has the inner diameter the same as the bore.
If you want a 9:1 CR
New cylinder large volume = 317.16cc
New cylinder small volume = 35.24cc
You need 0.819mm thicker gasket.

If you want a 8.5:1 CR
New cylinder large volume = 319.51cc
New cylinder small volume = 37.58cc
You need 1.31mm thicker gasket.

HTH
-Andy

phelpsa - 8/8/05 at 07:11 PM

Thanks Andy

phelpsa - 8/8/05 at 08:04 PM

Another question, is it worth intercooling?

Adam

nanosleep - 8/8/05 at 08:27 PM

quote:
Originally posted by phelpsa
Another question, is it worth intercooling?

Adam


Someone else should chime in here also.

Intercooling is good for reliability.
Under high boost the air temp exiting the compressor can be very high. This places a serious stress on the engine. You will also have problems with detonation at higher temperatures. Detonation = cracked/broken pistons.

Intercooling is good for performance.
The ideal gas law states: P*V=N*R*T
P is pressure, V is volume, R is constant, T is absolute temperature, and N is the number of molecules. For performance we want to stuff more molecules of air (oxygen in specific) into the engine. This allows us to squirt more fuel, and this gives us more power per bang. At a given boost pressure, P is fixed. V is related to the volume of the cylinder (and volumetric efficiency). V is fixed for a particular engine setup. So the only way we can increase N is to reduce T.
For the same boost pressure, intercooled will make more power than non-intercooled.

-Andy

phelpsa - 8/8/05 at 08:41 PM



To get minimum piping how about a top mounted intercooler impreza style? Looking at this picture the piping seems to be in exactly the right place for an impreza TMIC just infront of the engine. Also would an oil supply coming out of the sump, through the oil cooler, through the turbo and into the sump again be ok?

Adam

phil_far - 10/8/05 at 03:43 PM

Before lowering your compression ratio read this article from RB Racing who know a thing or two about turbos. Turboing a bike engine and turboing a car engine is diffrent philososphy. I alos recommend teh book 'Turbo, Supercharching bike engines' by Joe Hayle (hope ithe name is correct). Below 6 psi they always recommend stock compression!!

Specific Suggestions from RB Racing
Mechanical Considerations: Modern (1987 up) 4 valve/5 valve combustion chambers are generally not prone to detonation for brief excursions to 12 psi. Do not confuse boost psi with airflow in CFM. Turbo nozzle discharge @ 12 psi from a small turbo IS NOT the same as 12 psi from a larger turbo. RB Racing supplies only large CFM turbos that will produce more power at a given level of boost than will less efficient turbos without custom designed compressors. Your modern 16/20 valve engine is designed to breathe in the narrow window of 10,000+ rpm and, as such the effective compression ratio is less than the stated 11.0 to 12.0:1 manufacturer's static compression ratio. When you factor in camshaft duration necessary to allow sufficient inlet/exhaust overlap @ 10,000+ rpm your effective compression is much less. On (1987 up) motors we normally recommend you leave the stock compression/pistons in place. If you are hell-bent on "building" your turbo motor do not lower your static compression ratio below 10.0:1. For camshafts you can increase the valve lift but do not shorten the duration and therefore the overlap of the camshafts. Overlap on a turbo motor prevents overworking the exhaust valve by allowing cooling of the valve to take place which also helps to prevent the onset of detonation. In general the lower the compression ratio the more boost you can run and the more power you can make. If you build a 50 psi. 6.5:1 C.R> motor it will produce a lot of power but be a "dog" everywhere below this. Early (1979-1986) 2 valve motors and motors with less efficient 4 valve chambers probably need 8.0:1 compression ratios to survive. For your Honda we recommend you retain your stock connecting rods and pistons if you are going to run 180-225hp. For 25 psi blasts to 300+ horsepower we suggest forged pistons and Carrillo connecting rods. We refrain from recommending pistons. To achieve 360 hp on a Dyno you are going to best be served by augmenting your motor with Nitrous Oxide for two reasons: (1) The intercooler will be ineffective on a static dyno as no fan will simulate 200 mph airflow. (2) The NO2 will cool the inlet charge and provide a brief power boost. Normally we don't recommend the NO2 due to it's vagaries related to temperature/pressure etc. , but in the case of Dyno Heroes it's a necessary evil. Hit the "Squeeze" at your own peril!
Lock Up Clutch: Without this your clutch will slip pass 200 hp...Mandatory on high output turbo bikes.
Ignition: Leave stock item in place. Since you are hell bent on fooling with timing we will ask you one question..."What is your pressure/crank angle" at your new, guessed-at settings. Ignition is a difficult thing to evaluate. Bad designs use retarded ignition timing to prevent detonation . Retarded ignition brings its own can of thermal problems. Proceed at your own risk.