June Sprints @ Road America

[Jasonrmbell]

Well Glenn that's the part that i am not happy about... Stay Tuned.... I can tell you this I paid for a Fresh GD Motor... With Dyno Results with the Car package I spent the money on this it was extra. I cant tell you for sure whether i received that or not but what i can say is the motor in my car looked nothing like the fresh motor i purchased from NB for my back up that was just freshened and obviously as you can see it was down 20 HP and that does not make me happy either.

Still digging into this to get to the bottom of it i don't want to speculate but its hard not to.



J Bell

[scanworks1]

I see only one car has its diffuser ending right under the trailing edge of its wing. All others before. Hmmmmmmmmmm.
__________________
Lawrence Loshak
'10 DSR National Champion
'06 EP National Champion
Loshakracing.com


Lawrence - what car are you referring to??

chris

[Nicholas Belling]

I am nb.

I sold Jason bell an 07/08 engine. One that we were planning to use at the runoffs in our own firman car on the west coast. It was completely fresh and gone through and had no miles other than George's dyno from rebuild. But since we didn't run this season I offered it to Jason. A new comer to the fb world.

My engine Jason received was as advertised and it made excellent power as it was claimed to.

Jason dyno'd the engine his brand new car came with from stohr cars days prior to the sprints event recently. Then Jason ran my engine I sold him the day after the sprints on the same chassis dyno to compare. my engine I sold Jason made 21hp more than what he had in his car.

Obviously Jason wants to sort out what's going on as that would explain alot for his times and performance at the sprints being down 21hp!

Let us know what the outcome is Jason after you sort through it all.

[Jasonrmbell]

Absolutely will do. And yes the Nic B motor will be ran at Watkins G for sure. Working on sorting out the other motor issues now and hope to figure out what happened and how we wound up with this motor.

Never the less it's good to know I won't be lacking HP at WG.

Thanks Nic!

[RussMcB]

Four thoughts:

1. Post the graphs showing the difference between the two engines. Include the AFR trace, if available. That might provide clues about why the first engine is down on power.
2. Check all the easy stuff (under the cam cover, leak down, etc.). Use a Suzuki troubleshooting manual. If you're lucky you'll find something obviously wrong.
3. Call GDR and pick his brain. He'll probably suggest sending the engine to him, but maybe he'll have ideas about things you can check.
4. Call Sam Nelson (Nelson Engines, Cumming, GA) if you want to work with an engine builder closer to you.

Good luck.

[glenn cooper]

Some things I'm curious about:
Did the car rev out to the same RPM at each point on the track?
I have seen first hand (as in a car I rented and was told was "race ready") things that were absolutely not race ready - the throttle cable was not adjusted properly, and was a good 12mm from full travel!

I have seen simple small problems cause huge issues: MAP sensors hooked up wrong, the vacuum line from the one MAP not connected to the throttle bodies...

Hell at the Sprints I had eff'd up and had not connected the secondary throttle body quick connect on test day and the 2ndary plates were basically closing at 7k rpm (Talk about a rev limiter!) George Dean to the rescue = a quick call and we had it sorted in 5 minutes.

There's about 20 really simple things that can be responsible for a massive 20HP difference. Are you and your crew absolutely certain that everything on the first engine was installed/adjusted correctly?

Just a few thoughts, hope you guys get it worked out.

When you say the engine looked nothing like NB's, what exactly are you referring to?

[LLoshak]

I see only one car has its diffuser ending right under the trailing edge of its wing. All others before. Hmmmmmmmmmm.
__________________
Lawrence Loshak
'10 DSR National Champion
'06 EP National Champion
Loshakracing.com


Lawrence - what car are you referring to??

chris

Take another look. Only one car. Its interesting.

[scanworks1]

Originally Posted by scanworks1
I see only one car has its diffuser ending right under the trailing edge of its wing. All others before. Hmmmmmmmmmm.
__________________
Lawrence Loshak
'10 DSR National Champion
'06 EP National Champion
Loshakracing.com


Lawrence - what car are you referring to??

chris


Take another look. Only one car. Its interesting. June 21st, 2013 7:25 AM


Astra - Yes it is an interesting Design for sure

[Mike Devins]

[scanworks1]

ah - not astra - which one is this???


chris

[RussMcB]

The diversity of this class is really cool. It's very interesting to look at the different shapes and approaches, and they all seem to go very fast. And that's just the exterior. Take the body work off and it gets even more interesting.

It's not surprising this formula has attracted smart designers and fast drivers.

Plus, I guess we're starting to see something besides the ubiquitous Suzuki engine running in the front pack. Very cool (from a spectator's POV, at least).

[JakeL]

That's the Piper, as another one of the answers to the question above could have been "only one car has Dauntless endplates"

-Jake

[Mike Devins]

That's the Piper, as another one of the answers to the question above could have been "only one car has Dauntless endplates"

-Jake

But not the only one with HRP Diffusers!

[Jasonrmbell]

Glenn yes could be a number of things sorting thru it now. Initial feeling I was upset and really not wanting to jump to conclusions. Working it out now to figure out what happen.

I'm sure it will get figured out. Good I figured this out now prior to WG.


JBell

[Purple Frog]

The relationship between the diffuser and the bottom element of the rear wing is a very critical aero component. If positioned correctly the diffuser can make the main element a very efficient wing instead of just a crossbar that holds the endplates of the ground. The better the main element functions the less upper element that is needed, thus less drag.

[Mike Devins]

Aero if elusive stuff! Those of you that remember running around in a car with a sun roof may remember the little spring loaded wicker at the front of the opening, pull it down and it would set up a harmonic in the car that would just about pop you ear drums in an Beetle!

Put your hand out the window and play with the air coming off of the front windshield, 1/4 inch can make all the difference in what the air is doing. The relationship between wing and diffusers is much the same. Trial and error is required or CFD and correlation.

[JohnPaul]

Aero if elusive stuff! Those of you that remember running around in a car with a sun roof may remember the little spring loaded wicker at the front of the opening, pull it down and it would set up a harmonic in the car that would just about pop you ear drums in an Beetle!

Put your hand out the window and play with the air coming off of the front windshield, 1/4 inch can make all the difference in what the air is doing. The relationship between wing and diffusers is much the same. Trial and error is required or CFD and correlation.

So do you think extending the diffuser further back makes a difference? I remember you telling me that diffuser down force is made up in the front (larger the better)

[Brett Lane]

Not an aerodynamicist either, but I believe the air exiting the diffuser is moving faster than the air moving over the top- i.e. V/P=downforce. Therefore, having the faster(lower pressure) "licking" the lower surface of the wing is more desirable? If that is the case, you would not want to extend the diffuser beyond the leading edge unless there is some advantage to using the air coming over the top of the diffuser that I am not aware of.

I think...

[Mike Devins]

So do you think extending the diffuser further back makes a difference? I remember you telling me that diffuser down force is made up in the front (larger the better)

The diffuser should start as far forward as the rules allow and go far enough back to play nice with the rear wing. I personally like using bigger diffusers which allows you to run less rear wing.

[S Lathrop]

The down side of diffusers is that they are very sensitive to speed, pitch and ride height. Given the rules, the diffuser is primarily a rear down force device. So to keep the aero balance at various speeds, you need to gain front down force at close to the same rate as you gain rear down force.

Mike's advice is good for diffusers.

Remember that the top of a diffuser is frontal area at a point where you want the car to get smaller.

[pepperbowe]

Whoa - 3 pages and counting. Wait until I post images of the cars close up

[Jasonrmbell]

Any of Mine out there.

[glenn cooper]

here

[Jasonrmbell]

I seen that one from the Email link. FB look good on track all of them. How did the Kawi run for you btw. Seen the results were pretty good.

[glenn cooper]

ran pretty well it's first time out!

[glenn cooper]

The down side of diffusers is that they are very sensitive to speed, pitch and ride height. Given the rules, the diffuser is primarily a rear down force device. So to keep the aero balance at various speeds, you need to gain front down force at close to the same rate as you gain rear down force.

Mike's advice is good for diffusers.

Remember that the top of a diffuser is frontal area at a point where you want the car to get smaller.

...isn't the whole idea of rear diffuser to not actually gain rear d/f, but replace the manufacturing device from rear wing/high drag, to difuser/low/no drag?

[Nicholas Belling]

Not to mention we got the shifting in the Kawi to work pretty darn good with Geartronics.

Few more adjustments and shifting will be perfected.

It sure is a different animal over the Suzuki. Glen did a fabulous job retro fitting his car to accept the Kawi and to drop in the Suzuki if needed.

Kudos to Glenn for his 3rd full time job (the kawi project ) and making it happen.

[glenn cooper]

was typical Geartronics - "Hot knife, I'd like to introduce you to room temerature whipped butter - Oh wait, I see you've met!"

After hearing of the west coast Kawguys telling of difficult/notchy/stubborn shifting I was a tad concerned, but NO WORRIES at all.

Nicholas did his thing, and first time out it was damned near perfect, and a few keystrokes on the laptop later in the day made it even more perfecterer!

Thanks NB!

[R. Pare]

...isn't the whole idea of rear diffuser to not actually gain rear d/f, but replace the manufacturing device from rear wing/high drag, to difuser/low/no drag?

A bit of both. The center of pressure in most, if not all, FC & F1000 diffusers is behind the cars CG, so any downforce created is going to naturally be mostly at the rear, and with the changes in downforce that come with ride height and rake changes being much greater than the changes for a rear wing for the same, the cars aero balance will constantly change with changes in car attitude.

[S Lathrop]

...isn't the whole idea of rear diffuser to not actually gain rear d/f, but replace the manufacturing device from rear wing/high drag, to difuser/low/no drag?

Depends on how much shift in aero balance you are willing to tolerate. With FB, you have a power down issues at low speeds. At low speeds, say 60 mph, you might have a good balance but at high speed, say 120 mph, you might see more than 10% shift in aero balance to the rear. Now you have a car that is slow off some corners because of push. At 150 mph, that shift will be 25% or greater. This is a bigger issue for FB than FC because of the substantially higher speeds possible with a FB.

At RA you need a balanced car to get off the 3 slow corners but you also need balance for the carousel and the kink. With a big gain in rear down force at speed, you might be slow at a critical point on the track. You also want good rear down force to help stick the rear under hard acceleration. Because we tend to go with low down force settings at RA, the issue might be worse than with an aero setup for say Road Atlanta or Mid Ohio.