No Straight Away Speed in Spec Class

Kstrycharz07

Kstrycharz07

Member
I have been having a constant struggle in my 2 years of karting. That is never having top end speed or getting the level of RPMs the other guys do.

Some background about what I race. I have a 2008 Coyote SS chassis running a just passed stock clone. My series is the NYKA and everyone has sealed motors with the same parts. The only things we can change on the motor are springs, spark plugs and carb jets. I am running 18lb springs and so is everyone else

So citing the motor as the sole issue is not an option.

I am the quickets guy in the corners pulling 1-2 kart lengths after turn out I just have no acceleration or top end. This is even the case when I am running the same gear as other guys (12-62) at the home track (MXK Hotshot Raceway) and (14-62) at GVKC in Avon NY.

The series organizer builds/techs all motors and has been lecturing me about bind on straights. I have been taught to take away camber, and caster. Loosening bumper and nerf mounts to make the kart more free. Currently I am running 0 toe, 0 camber, and I am backed off on caster significantly. Also scaled the kart to get 50/50% left to right The only things I never played with is seat position and carb jet size. I have noticed my motor is ever so slightly crooked, but the organizer said that wouldn't impact it that much.

I am just getting very frustrated now. I cannot be competitive without that top end speed. I feel like I have checked every box to limit bind down straights.
 
Dirt oval racing ? Sorry just realized it's sprint which I know nothing about BUT NO CAMBER to get roll speed does not sound right to me, more contact patch more resistance doesn't matter what you race. If your confident it's not motor It's gearing.
Good Luck !!
 
Not a sprint guy either .
Engine being sealed , does not negate it from the equation .
Weight and height affect plenty .
You pass everyone going into and through the turn only too get passed again by the same karts ?
 
racing promotor said:
Dirt oval racing ? Sorry just realized it's sprint which I know nothing about BUT NO CAMBER to get roll speed does not sound right to me, more contact patch more resistance doesn't matter what you race. If your confident it's not motor It's gearing.
Good Luck !!
Click to expand...
It cannot be gearing I am running the same as other guys as well... but they pull me multiple kart lengths in straights if I am getting passed they sound a lot higher revving than me and they are running the same gear.
 
flattop1 said:
Not a sprint guy either .
Engine being sealed , does not negate it from the equation .
Weight and height affect plenty .
You pass everyone going into and through the turn only too get passed again by the same karts ?
Click to expand...
I cant complete a pass in corners but I shrink the gap a lot in corners but lose it all in the straights. Usually 3-4 tenths a lap slower.
 
You can run the same gear as them, but let’s say your right sides are 33-1/2 and theirs are 34-1/2, they will have more speed then you cause you’ll out of the rpm range for that spec motor before they will.
 
Fast in the corners, slow down the straights = better driver, no HP.

Or, and there are a ton of "or's", something else.

Stock class?? Are they? How about tech, do they degree the cams? Do they check the lift? Do they check the valve size. It goes on and on.

Get that chain alignment fixed!

Get a compression check! You should have your own gauge, get a good one, Pep Boys doesn't sell a good one. Check it often!

Have you checked the combustion chamber cc's on your engine? How thick is the head gasket?

Have the engine dyno tested if possible!

What about jetting? What about timing? What about valve lash? What about the clutch? It just goes on and on.

It's called tuning! "And tuning is tough" (Al Nunley)

Get that chain alignment fixed!!

1 inch in tire circumference is about 3 teeth (#35) on the axle. Not exactly, but close. Actually a little less then 3.
 
alvin l nunley said:
Fast in the corners, slow down the straights = better driver, no HP.

Or, and there are a ton of "or's", something else.

Stock class?? Are they? How about tech, do they degree the cams? Do they check the lift? Do they check the valve size. It goes on and on.

Get that chain alignment fixed!

Get a compression check! You should have your own gauge, get a good one, Pep Boys doesn't sell a good one. Check it often!

Have you checked the combustion chamber cc's on your engine? How thick is the head gasket?

Have the engine dyno tested if possible!

What about jetting? What about timing? What about valve lash? What about the clutch? It just goes on and on.

It's called tuning! "And tuning is tough" (Al Nunley)

Get that chain alignment fixed!!

1 inch in tire circumference is about 3 teeth (#35) on the axle. Not exactly, but close. Actually a little less then 3.
Click to expand...


I did forget to mention I have noticed that the engine mount is crooked ever so slightly... It is an older ARC clone mount, I have no idea how to fix it. I never thought of that robbing power.
 
If your carb. Setup is not perfect you are leaving a lot of money on the table. Getting it right can really wake up an engine.i would get a high quality motor mount an play with carb. Do some practice days and keep a notebook. What you did and how the kart performed.
 
Kstrycharz07 said:
I cant complete a pass in corners but I shrink the gap a lot in corners but lose it all in the straights. Usually 3-4 tenths a lap slower.
Click to expand...
Get someone too turn a few laps in your kart . If they improve the lap times . There's one answer .
 
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Gap will naturally appear to close in a corner.... .3 at 30 mph looks a lot different that .3 at 60 mph. Therefore, I'm wondering if your setup is "bogging" the engine and they're getting more RPM because their setup is more "free" and allows them to accelerate more quickly and longer, which equals more RPM. This is a low-hp engine, which means your setup has to be dead-on to allow for the inside rear to lift enough to skate through most of the turn. Sliding will burn hp and acceleration. Just a thought.
 
alvin l nunley said:
Fast in the corners, slow down the straights = better driver, no HP.

Or, and there are a ton of "or's", something else.

Stock class?? Are they? How about tech, do they degree the cams? Do they check the lift? Do they check the valve size. It goes on and on.

Get that chain alignment fixed!

Get a compression check! You should have your own gauge, get a good one, Pep Boys doesn't sell a good one. Check it often!

Have you checked the combustion chamber cc's on your engine? How thick is the head gasket?

Have the engine dyno tested if possible!

What about jetting? What about timing? What about valve lash? What about the clutch? It just goes on and on.

It's called tuning! "And tuning is tough" (Al Nunley)

Get that chain alignment fixed!!

1 inch in tire circumference is about 3 teeth (#35) on the axle. Not exactly, but close. Actually a little less then 3.
Click to expand...
Do what Al said. Stop looking for the magic bullet and start making tiny incremental things that add up to 3or 4 tenth.
collect, review andmuse your data.
 
If your tire psi is low it will give you more rolling resistance. Do you set your toe with the driver in the kart? Also less caster will make you squirlly on the straight, more caster will keep you steady.
 
Kstrycharz07 said:
I did forget to mention I have noticed that the engine mount is crooked ever so slightly... It is an older ARC clone mount, I have no idea how to fix it. I never thought of that robbing power.
Click to expand...
Just wondering; of all the things I mentioned, how is it you pick that one thing out to mention?
 
sundog said:
If your tire psi is low it will give you more rolling resistance. Do you set your toe with the driver in the kart? Also less caster will make you squirlly on the straight, more caster will keep you steady.
Click to expand...

Toe was set with a laser toe gauge with me in the kart, It is set to 0. The series offical has been racing forever and he always tells me "Caster will kill a low HP motor"

Could ride height make a big difference??

Replying to Al, the motors are sealed so I cannot check degree of cams or change valves. I could try jetting more but I am already running rich, whenever I pull the plug it is black. I am using a AR3910X. Valve lash, I have not checked, but I recently got the crank, rod, and piston, and rings replaced. I ran fully synthetic oil not knowing better and ruined the crank and rod.

I have looked a lot of places about Carb setup but I really have no idea where to go. We run Ruiking carbs and the only modification is that they are jetted. We need to run a marked carb by the series organizer so the only thing I could legally change is the jet size.
 
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