Does anyone know what kind of power increase to expect off of a 2001 750?

anyone?

too many variables. depends on who does the work, what cams, exhaust, etc. maybe 3 to 7hp as a guess...maybe more bt unlikely i think...

You dont want to polish the intake side.. It will reduce fuel atomization, and the fuel may begin to pool and reduce HP..

any direct experience

I know polishing the intake ports will reduce turbulance, but since the injectors are below the PTV, isn't the majority of atomization focused around the injector?

Would unshrouding the injectors help?
K.

Krispy said:
I know polishing the intake ports will reduce turbulance, but since the injectors are below the PTV, isn't the majority of atomization focused around the injector?

Would unshrouding the injectors help?
K.



This isn't directed at you Krispy, but there seems to be a misunderstanding about the fuel air mixing thing. Probably a relic from the drivel published in car magazines concerning carburated engines with the carbs a long way away from the cylinder.

The current GSXR line fires its fuel injector on top of a closed intake valve. Much of the fuel is injected with no air flow what so ever, much less turbulence.

Remember that picture in the Suzuki propaganda of the injector firing on the PTV and the fuel plume going into the airstream? That's fuel evaporating off of the the throttle blade after the injector has been closed for awhile in most cases.

There are several ways to get fuel and air to mix, but first the fuel must evaporate. Finer droplets help. Throwing fuel on a frying pan works really well, which appears to be what Suzuki chose to do. It's not a lot different than the heated pad under the carbs of cars.

Don't take my word for it, check out the service manual.

Don't forget that at redline the injectors are at a 60-70% duty cycle. The intake valve only has around a 30% duty cycle (a bit over 200 out of 720 degrees) and the intake runner is only about five inches long. There is no choice but to spray on the top of the valves.

I think I understand what is being said,...which lead me to my next Q.

1) Why is there so much opinion about intake fuel runners and turbulance, when it is not really directly related to fuel atomization.


2) AND are these really intake runners or casting flaws? Can them be gound off for performance increase?

http://68.144.228.120/web/intakerunners.jpg

Tks for the info gents.
K.

Krispy said:
I think I understand what is being said,...which lead me to my next Q.

1) Why is there so much opinion about intake fuel runners and turbulance, when it is not really directly related to fuel atomization.


2) AND are these really intake runners or casting flaws? Can them be gound off for performance increase?

Tks for the info gents.
K.



On 1), I think we live in a single sentence sound bite world these days. There is a lot of good information on the internet, but it is mixed in with a much larger percentage of crap. A lot of the crap starts as good information that looses its relevance as the context is lost. The coarse intake runner thing was important with carburated V8 car engines. The flip side of this is there is no benefit to polishing the intake under any circumstances, so why pay for it?

2) That is the parting line for the intake port casting core. It has no significance to performance and is a relic of the manufacturing process. If you want most of the benefit of a $1200 porting job, it is accomplished with the surfacing machine and modifications within 1/2" of the valve seat.

Infrequently, you'll find castings that are so ugly they really need porting. The best bet would be to spend $150 and start with another casting. The really ugly ones show up in the alignment between the port and the valve seat.

Jeez Krispy, you're turning me into a post whore tonight.

I'll let you know next Saturday. Gonna run mine on the dyno after having the heads done. Butt dyno says that it improved. Hard to get a graph though.

MrMW said:
Jeez Krispy, you're turning me into a post whore tonight.



My job here is done.
Seriously though, sometimes I just need to be told rather than to read it.
I appreciate your time/info/effort.

Thanks.
K.

http://www.gixxer.com/forums/images/graemlins/thumb.gif

You Americans seem obsessed with all the glitz and shinny bits you can bolt on a bike. Our GXR 1000 race bikes put out over 180hp on a corrected Dynojet Dyno. All this is achieved with quality parts and good R&D. Yoshimura parts will do nothing for the bike and are designed for the Bolt-on brigade which has a wide audience it seems in your country! Power in the GSXR's is centered in the inlet ports and cams, taken that you use a quality exhaust system of course. Polishing the ports might work on your big V8 engines that have the class and finesse of a brick, but will have no effect on most modern sport bikes. They need smaller ports not larger after they have been polished. Center all quality porting around the base of the valve and seat area. There is only one real cam working at moment and thats the kit being used by Crescent Suzuki in the UK, use Yoshimura titanium collets, and suitable high comp pistons. Then the tricks start in the crankcases, but since we are not allowed to do that in Australian racing, I know absolutely nothing about it !!!!!!!! Most of all careful construction is important using the kit .4 head gasket (might not be available in USA, its not in Aus have to obtain from the UK). Then u have 180 + hp on a street tyre (more on a slick) on the dyno. The next problem is can it be ridden and set up by the average rider on the street, NO. We have the world Endurance Champion on ours and its a handful either at the front under power or the rear under power, finding a balance is the key!

twosheds said:
You Americans seem obsessed with all the glitz and shinny bits you can bolt on a bike. Our GXR 1000 race bikes put out over 180hp on a corrected Dynojet Dyno. All this is achieved with quality parts and good R&D. Yoshimura parts will do nothing for the bike and are designed for the Bolt-on brigade which has a wide audience it seems in your country! Power in the GSXR's is centered in the inlet ports and cams, taken that you use a quality exhaust system of course. Polishing the ports might work on your big V8 engines that have the class and finesse of a brick, but will have no effect on most modern sport bikes. They need smaller ports not larger after they have been polished. Center all quality porting around the base of the valve and seat area. There is only one real cam working at moment and thats the kit being used by Crescent Suzuki in the UK, use Yoshimura titanium collets, and suitable high comp pistons. Then the tricks start in the crankcases, but since we are not allowed to do that in Australian racing, I know absolutely nothing about it !!!!!!!! Most of all careful construction is important using the kit .4 head gasket (might not be available in USA, its not in Aus have to obtain from the UK). Then u have 180 + hp on a street tyre (more on a slick) on the dyno. The next problem is can it be ridden and set up by the average rider on the street, NO. We have the world Endurance Champion on ours and its a handful either at the front under power or the rear under power, finding a balance is the key!



Now that's what I'm talking about!!!! More about that cam setup?