Horseshow Manager

0HP RESEARCH

Write up on the engine can be found here: https://www.corvetteforum.com/forums/autocrossing-and-roadracing/4128723-hpr-and-gspeed-at-it-again-with-a-442-cid-ls3-c5-road-racer.html

I'm sure Grant and Louis have a number of pics of the rest of the car build too!!

Super cool build and a way different animal than what it was before!!

Shortcutsleeping

Having driven this combo in anger now chasing that 991.2GT2RS, I can emphatically say that the HPR boys have completely hit the mark.

The Cresson 3.1 configuration has two places where you're coming out of slow corners and going UP a hill and the super flat torque delivery of this motor makes it just so easy. That weekend I passed a TON of cars and this combo just made it so effortless. No heat issues, no oil pressure issues, wiiiiiiide powerband and lots of usable RPM.

Kudos to the HPR and the GSpeed gang for a fantastic execution of an easy-to-drive and very fast "no excuses" track car!

Costas
cars and such...

STANG KILLA SS

gonna study this vid 50 times lol.
i saw that car on the grid sunday too. never go to see it up close.
witchdoctor motorsports? i recognize that name? from a few years ago?

cant wait to meet ya. could definatly use some advice and help with my still street legal hoopty.

great lap and car!

dclafleur

I hope to check out this car in person sometime this year. Do you have any track days out at Hallett planned?

Horseshow Manager

Yes, I live in Broken Arrow OK and Hallett is my home track. Going to run the PCA event there in a few weeks! Come look me up.
Grant

Shortcutsleeping

The biggest thing you'll likely notice is I don't use engine braking to slow the car down. I use the 'wait until you are within 1 second of needing power and then quickly downshift' method.

This does several things:

• I can completely focus on entry speed* and turn-in point
• Once braking, I can focus on the exact pedal pressure I need without getting into abs
• When I do shift, the rpm delta is very low
• I can shift from 4th to 2nd directly and instantly (and do twice in the vid)
• When revving the motor to downshift, you're stretching rod bolts, using fuel and creating heat. I see no reason for it.
• If you get really good at carrying mid-corner speed you will have time to quickly shift just prior to needing thrust
• Would you rather change brake pads or a clutch? heh

While doing the rev/downshift thing in the early-to-mid braking zone may 'feel' fast because you are busy, it isn't.

My lines in this vid are nothing phenomenal, (not my car, I'm not going to risk it!) but they are solid lines that worked well. In my own car or in a TT competition I'd have altered them a bit. No biggie.

I get a lot of emails/DMs when I post vids that I'm doing it 'wrong'. <shrug> When we posted the fast lap from May at COTA several folks called me out. LOL.

*entry speed = In my years coaching/testing/helping I've noticed that everyone is fast on exit. Fast guys are fast in the middle AND on the exit. And the really fast guys are fast on entry. A pro race engineer (legit guy, full time factory paid, etc) I work with said "the Gods live on corner entry" and as the years go by, he is consistently proven correct. Entry speed is where it is at. To focus on that, I don't like to clutter my mind with downshift thoughts or mess up my braking pressure trying to heel/toe. I also don't like putting heat into my engine, stretching rods/bolts or burning more gas. The technique is a big win win (at least for me).

Yeah, Grant (car owner) was out chasing PCars and giving them hell until he wore the tires out! <LOL>

I started WDMS in the 90s doing some IMSA stuff.
www.witchdoctormotorsports.com
We do nasa/scca sprint racing as well as WRL stuff, did stage rally, race airplanes, etc. Wife has a pcar and a TTsupra drag car, blah blah. We play with cars.
I drive for GSpeed and we won nats at COTA. Our TT3 record there is a 2:22 with 270rwhp. I'm still shocked we went that fast.

Sounds like you're on the right path, but I'll tell you the same thing I tell folks I coach and the FSAE team I've advised since 99:

Asking questions is great. Just be careful who you listen to. Remember a camel is a racehorse designed by committee. Everyone has their opinion and that's cool but a damn fast way to get lost is to listen to folks who speak loud with no experience (or verrrry little). Yet, on the internet, they can type just like anyone else. And argue. And sound like they know what they are talking about. Be careful. Be prepared to test everything.

I'll be at Cresson this weekend with NASA if you're around.

Thanks! Grant has a really fun car and Louis and GSpeed crew did a fantastic job on setup. I just helped with fine-tuning :-D

Costas
cars and such...

Horseshow Manager

Thank you Paul!
It was a pleasure to meet you and I am looking forward to spending much more time at the track with Team GSpeed!
Perhaps I will get fast enough to get some BIG decals😃

Mulepower

Costas..........are you the same Costas that did a write up on a GT1 car you nick named "Scratcher" I think it was???? If so, that article inspired me to buy a mid 80's IMSA TA car, which is sitting in my garage currently. But now I want a vette.

0HP RESEARCH

One in the same... https://horsepower-research.com/blog...aro-in-history

Shortcutsleeping

LOL. What write up did you read? (and as HPR said, yes that's me)

I was in NASA SpeedNews for the 40-wins-in-a-row thing...which was pretty cool.

More importantly, what car do you have for sale? Link?

C5 and C6 vettes are soooo nice and can be built into incredible track weapons.

I currently drive the C5 "SLJHMR" for GSpeed (same folks who did Silver Surfer for Grant here). We all use HPR for engines.

SLJHMR just won NASA NATS at COTA last year...incredible C5 to drive as well. If you're bored, here are some recent stories:
NASA event in May: http://www.witchdoctormotorsports.com/ch263.htm
Testing: http://www.witchdoctormotorsports.com/ch268.htm
NATS: http://www.witchdoctormotorsports.com/ch269.htm

Are you in Texas?

Costas
cars and such...

Mulepower

So you were battling with Foesler at COTA then. I actually bought his transmission out of his 65 coupe for my car. I'm in Ohio, but I bought my car in Texas. Does that count?
heres my car

https://www.racingjunk.com/GT/183159...Am-Camaro.html

Not sure what article I read, but it had pics of scratcher in purple and white paint I think.

emptnest

I’ll put on my flame suit and ask the embarrassing question:

How do you maintain traction and your driving line when changing gears in the turn?

Everytime that I have ever shifted in a turn, my rear end gets loose as soon as I press the clutch; often resulting in a loss of control and a spin out.

Thanks in advance for for any tips.

Shortcutsleeping

LOL....no flame suit needed here. If we can't discuss driving style in the 'autocross/roadrace' forum then that would be horrible!

I guess it would be situation dependent, but let's cover some generalities and see if what I'm thinking can come across to you.

First caveat = I've been doing this a while and this way works for me. I've seen really fast folks use very different styles and obviously the ultimate judge is the stopwatch.

For me, however, I'm a budget racer and I want A) to go as fast as possible and, B) to be as easy on the equipment as possible.

If the car gets loose when you push in the clutch then my guess is you are likely still in the 'middle' of the brake zone and not near the end. I typically wait till I'm within a second (or half second) of needing power to execute my shift. That typically occurs once the majority of speed has been bled down and I'm in that short 'coast' section where I'm letting that last bit of speed bleed off by slip angle of the tires and I'm waiting to get to the piece of pavement where I go back to power.

This would be much easier to explain if we could go for a drive. LOL

Next best thing is some video!

This is the GSpeed's C5 "SLJHMR" in January setting track record at MSRH. Previous record was a 1:39 and we took it to a 1:35, so this is a very competitive lap. If you'll note at 1:50, 2:10, 2:30 (etc), I'm downshifting in a corner, but I've waited till most every bit of speed is gone, so the shift is quick, effortless and very little wear on the clutch or the syncros.

Back in GSpeed's "SLJHMR" winning nats in the biggest TT field at nats, so again this is a very competitive lap. Take a look at 0:40, 1:04, 1:30, 2:15, 2:45, etc.

This is Scratcher, a tube car with a dog box, but I still use the clutch to make it easier on the dogs and to lessen the violence/impact of weight transfer.

This is Pontini, a 4th gen Firebird v6/5speed endurance car...

In all these you'll see I bleed speed with the brakes exclusively, and the goal is to have only a few extra MPH at the end of the corner entry where I have a moment to clutch/shift and then when I get to the power-down point on the track I'm at the right speed, pointed the right way to use the loud pedal. Between reading this and watching a bit, I hope it makes sense.

Again, maybe this is not a technique for everyone, but it has rewarded me a ton.

An engineer friend of mine saw my January vid at MSRH and was testing there in February and changed from the downshifting-early technique to downshifting ultra late and in only his second session practicing it he was picking up ~.2 in turn 1 and ~.3 on the other high-speed corner on the backside...and he found it easier to do, he was 'less busy' in the car and was more effective at placing the car exactly where it needed to be. He was stoked to pick up ~half a second and make his life easier. With his AIM SOLO he base-lined his normal driving the first session and got consistent data, then for the second and third session he changed to ultra-late-down shifting and although it "felt slower" he was faster.

It "felt slower" because the chassis was more stable. It is like when you're in some high speed esses and you run them at the top of third gear. Every minute little change in the throttle makes a huge pitch (nose up or down) change in the chassis and stability suffers. But, run the esses in 4th gear and the car is stable and you'll end up running a quicker time but it will "feel" slower. Some folks will say "but I'm in the powerband in 3rd" but you can't use full throttle so it does not matter. Hope that make sense.

Again, driving is one of those things that two folks can do really differently and get the same lap time. For me, this works and it is easy on equipment.

Happy to help and please ask any questions that I inadvertently spawned or that I missed.

Costas
cars and such...

Shortcutsleeping

Nope, I was running in TT3 and battling Schotz and thankfully coming out on top.

TTU (where Faessler ran) was won by another GSpeed prepped car owned/driven by Troy Messer.

TT3 "SLJHMR" and TTU "Messer"



Who did you buy that yellow car from? Looks really nice on the outside. Do you know who built the chassis?

Might have been a link to my website www.witchdoctormotorsports.com
I have a lot of build chapter on there about the build of that car.



The beginning chapter: http://www.witchdoctormotorsports.com/ch42.htm




Costas
cars and such

STANG KILLA SS

cool to see others that followed the same 4th gen to vette path that i did.
looks like you even experienced the joys of optispark too

mfain

Great thread. Thank you. I am really looking forward to getting my project finished and spending some time on track out your way.

Pappy

Mulepower

Costas, I sent you a PM about my car.

emptnest

Costas, thanks much for the helpful videos and the expert explanations.

I will work on adopting your technique.