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chkdsk

To the ST6 guys – HP and Dyno charts

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We had a great chat last race weekend about what to do and the topic of some of the dyno pulls came up.  We were talking about sharing info and I apologize for not being able to post sooner as real life keeps getting in the way of this racing stuff.

Here’s some info I have:

Factory D16 when it was in IT3. Rules were strict and not much was allowed. We did several pulls with different IT3 cars trying to see if there was something we could find as the #2 would always pull us on a green flag drop drag race;

-          Cold air intake
-          Header
-          Chip
-          4.9’ (I think it was 4.9’s, could have been 4.7’s)
-          Factory pistons, factory everything
-          No cam
-          I think that’s it.

image.png

 

This next one is the exact same engine with only one difference; Cam (Colt Tri flow)

image.png

 

Some notes from me:

-          I have never been under 111HP with a D16 even with a factory header in Clint’s CRX last year. This is how we have always done the spec weight for our cars and one year we had to add 135 lbs to a car to meet spec.

-          Take a look at how the Power drops off on a D16 non-cam car, the math shows that you should shift at 6750 to keep the top of the curve in your shift to even out what you lose. No point in losing more HP revving it higher just to wait to shift.

-          The 2nd Dyno shot is Clint’s car as it sits right now with a Colt cam and he is bang-on spec weight for that HP as we had to add a pile of weight previously. Whoever is running Cam’s need to get their weight dialed in as my car is cam’d and I’m 80 lbs heavy even with Cam so if you’re under spec weight and you’re passing me then I’ll be pissy 

-        I can see the frustration of other racers trying to get their weight down to spec if they're basing it on 105HP as that is damn light car although I've never seen that low of HP on a Dyno with a D16. Maybe an Non-SI? Or a 1500?

We could look at doing an experiment as I have exactly what our cam cars are at the one vendor and I could book at the other vendor to see if it is the same or if there is a delta? 

Thanks to the guys that were part of the chat last race Sunday, it was constructive and good info was shared. 

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Thanks Jordan! I took my car to speedfactor's dyno the morning after our last race. Peak hp was 117hp, similar to Clint. Sorry I don't have a scanner to post the dyno sheet but I will bring the paper dyno sheet to the next race in case anyone is curious. Using NASA's ST car classification form https://form.jotform.com/drivenasa/st-tt-car-classification-form my power to weight ratio was just over 18, so ST6 legal.

FYI - post race inspection showed terminal chassis cracks in my CRX! That car is done for good :(. But the engine might return in a different chassis.

I think some of the 105 hp guys are no longer only 105 hp ;). So maybe the ST6 power to weight ratio of 18 will prove to be OK.

It would be nice to have the scales available again so we can verify weights as well.

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Scales will be out and active for RR#3. 

IT3/PTE/CCC/PTF and now ST6 has been the largest class for many years. If we want it to stay that way we all need to embrace the true spirit of club racing and be as honest and forthcoming with information on our set ups. 

I truly hope that by now EVERYBODY has a dyno sheet. There is no excuse left to validate not having one. 

I know what it’s like to blow thousands and thousands of dollars being stuck 2 seconds behind the lead cars. Eventually you just walk away. Sharing information and getting everyone within a proper and honest HP/LB ratio will help keep the class thriving. 

 

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On 7/26/2019 at 7:01 AM, Mat said:

IT3/PTE/CCC/PTF and now ST6 has been the largest class for many years. If we want it to stay that way we all need to embrace the true spirit of club racing and be as honest and forthcoming with information on our set ups. 

Completely agree. If you beat me with twin cars then I'll be the first to buy you a cold one.

Several years ago when I thought I was Formula Un and there was no way my car could go any faster, Marcoux jumps in it during a Saturday night worker laps and does 5 or 6 laps and beats my best time by over 1.5 seconds. That was in an unfamiliar car and with him using a booster seat. That was the first time I had to say the words out loud "Huh, guess it's not the car" which was a good/brutal moment for me as it forced me to go back and dig down and pull some more speed out out of my brain. 

One part I forgot in my list above is that the last pull had lightened flywheel although not the first one as that was illegal in IT3. 

On 7/26/2019 at 7:01 AM, Mat said:

I truly hope that by now EVERYBODY has a dyno sheet. There is no excuse left to validate not having one. 

Having the Dyno sheet is one thing although the big issue to me is that the cars still need to be their spec weight from the Dyno sheet. In our fleet #44 is the only one that is bang on weight with HP and there are two competitor cars that can constantly pull him in a green flag drop drag race which means a) they either have more HP than reported OR b) their cars are under their weight. Everyone has to be at their weight as we had to add a pile to #44 for his 117HP. 

My car is fat and is going on the Keto diet before next race as she's been doing too much bread. And cake. And maybe too many barley pops. 

 

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1 hour ago, chkdsk said:

My car is fat and is going on the Keto diet before next race as she's been doing too much bread. And cake. And maybe too many barley pops

Don't forget the hot dogs! Maybe bottle the burps as octane boost?

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37 minutes ago, nopistons said:

Don't forget the hot dogs! 

Yes, Hot Dogs too. And Farmer sausage. She's such a pig... and no manors either. 

 

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Not sure if you guys care about how to calc average HP for your magic spreadsheet although you should. This is how we did it from the Cam Pull from above: 

image.png

 

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