THE BACK ROOM or ....

[jjjanos]

I do tire some of hints at solutions without discussion of them. If the solution is to bump the power to weight ratio in ITB to 18:1, as I said before, I think that carries a heavy price with new car/driver participation in ITB.

Discuss please.... If the new cars are competitive with existing cars, why is this such a downside?

For me two big concerns are the 18.84 ratio for ITC (and the implied weights for existing cars) and the apparent randomness in the difference between class ratios.
ITR->ITS Gap: 1.65
ITS->ITA Gap: 1.6
ITA->ITB Gap: 2.5
ITB -> ITC Gap: 1.4

At least to me, there appears to be no rhyme or reason to the step increases.

 

[jjjanos]

if it's for ITB in total, what difference does it make if the P/W is 17.1 or 18 or 36?

Because picking a number too low runs the risk of moving a lot of cars down to ITC, not because they aren't ITB cars, but because of a unilateral change in philosophy.

 

[jjjanos]

I'm clearly missing something...or somethingS...

The Volvo is competitive at current weight with the most already listed cars because those cars are fat.

Lose the weight from the tenured ITB cars to bring them in line with the newer listed ITB cars and the Volvo won't be.

Whether that problem can be rectified with inve$tments in suspension components remains to be seen and debated.

As an ITC car, using the 1.25 gain, it would be heavier than the New Beetle and really have a chance of being a class killer.

At its current weight, there are VERY few ITC cars that can get near it (especially at a HP track). Would throwing weight fix that? Dunno.

 

[jjjanos]

We will NOT get to that level of evidence here so please (JJJ) don't jump all over this as an example of how it doesn't work.

The problem isn't with the ad-hoc. The problem rests with the real decision-making body, i.e. the group that was the problem last summer and who are the reason so many requests to look at weight went down a rabbit hole.

 

[gran racing]

3- When was the last time a Sam Moore/Curren/BHP whatever car ran at top prep level at a top event with a top flight driver? Sorry if you find my comments insulting...

Sam and I raced at Mid Ohio a couple years back and we were nose to tail the whole race. When Eric got in the car, he did what, 1/2 second faster than the lap record which has stood for many, many years? But again, that's all on track performance which shouldn't matter, although Charlie likes looking at that information.

I'd absolutely hate to see a blanket "all ITB cars add 50 lbs" to the class.

 

[Gary L]

You volvo guys... get ready to type!

I know I'm going to get PM's and emails, because I certainly did the last time I ran these numbers in this forum, but so be it. I'm tired of the inaccuracies being semi-legitimized by these discussions about my favorite ITB car.

Jake - I don't know where you found your DIN-to-SAE net conversion factor, but it's dead wrong. The real numbers are... 100 DIN = 98 SAE net, give or take a small fraction of one hp. Your numbers look more like an approximation of DIN-to-SAE gross.

Anyway, the DIN rating for the B20E Volvo, as installed in a 140 series car, was 124 (and that's from the shop manuals, not Wikepeeonya. ) Multiply by .98 and you have 122 stock flywheel SAE net hp. If you multiply 122 x 1.25, you come up with the 152.5 hp, or within 1.7% of the 150 hp "known" legal IT builds run across a reputable dyno. So - let's use the "known" 150 because it seems very legitimate. Multiply 150 by 17 and you arrive at 2550. Add 50 lbs for double wishbone front, 'cuz that's in the process. This puts us within 40 lbs of the current GCR listed 2640. But in all honesty, the car deserves at least a consideration of weight subtraction for the combined effects of:

1 - live rear axle
2 - terrible aero (cd is somewhere north of .40 IIRC, and it's huge to boot)
3 - drivetrain loss greater than average rwd (1950's gearbox design)

So just put it at 2600, maybe 2550 and get on with it. This is NOT an ITC car.

 

[tnord]

i was hoping you'd show up eventually Gary.

i think the confusion around moving the car to C has to do with the Volvo 240, not the 142.

 

[Harvey]

Gary

I never proposed moving the 142 to ITC. The 240 cars on the other hand according to the process are ITC cars.

The bottom line here is to try and correct some problems.

 

[Gary L]

Gary

I never proposed moving the 142 to ITC.

I know you didn't... but there are a lot of people on here talking about that possibility, and it just doesn't make sense... ergo my comment.

 

[tnord]

there are too many old volvos to keep track of. my notes from the last meeting indicate all discussion around moving *Volvos* to ITC were around the 240.

i think jeff just had a little brain fart. to my knowledge moving the 142 to C isn't currently on the table.

 

[StephenB]

Thank-you for clarifying the 142 vs. 240. Based on this thread and the posts from the ITAC I honestly thought they were considering a huge reduction in weight or moving it (142) to ITC. I was getting very concerned at the direction we were heading!

I will now go back under my rock and lurk

Stephen

 

[JeffYoung]

Yep, big brain fart. My bad guys, that car obviously is not a C car as it is already close to process weight.

there are too many old volvos to keep track of. my notes from the last meeting indicate all discussion around moving *Volvos* to ITC were around the 240.

i think jeff just had a little brain fart. to my knowledge moving the 142 to C isn't currently on the table.

 

[lateapex911]

I know I'm going to get PM's and emails, because I certainly did the last time I ran these numbers in this forum, but so be it. I'm tired of the inaccuracies being semi-legitimized by these discussions about my favorite ITB car.

Jake - I don't know where you found your DIN-to-SAE net conversion factor, but it's dead wrong. The real numbers are... 100 DIN = 98 SAE net, give or take a small fraction of one hp. Your numbers look more like an approximation of DIN-to-SAE gross.

Anyway, the DIN rating for the B20E Volvo, as installed in a 140 series car, was 124 (and that's from the shop manuals, not Wikepeeonya. ) Multiply by .98 and you have 122 stock flywheel SAE net hp. If you multiply 122 x 1.25, you come up with the 152.5 hp, or within 1.7% of the 150 hp "known" legal IT builds run across a reputable dyno. So - let's use the "known" 150 because it seems very legitimate. Multiply 150 by 17 and you arrive at 2550. Add 50 lbs for double wishbone front, 'cuz that's in the process. This puts us within 40 lbs of the current GCR listed 2640. But in all honesty, the car deserves at least a consideration of weight subtraction for the combined effects of:

1 - live rear axle
2 - terrible aero (cd is somewhere north of .40 IIRC, and it's huge to boot)
3 - drivetrain loss greater than average rwd (1950's gearbox design)

So just put it at 2600, maybe 2550 and get on with it. This is NOT an ITC car.

An article by Road and Tracks engineering editor comparing the different hp standards around the world. Other systems were discussed in it, but those weren't pertinent.

No other car gets a live rear axle break except now ITR cars. So, if the Volvo were to get one so would many others. So, no to 1.
Lot's of cars are supposed to have bad aero. How much are under car issues which are mitigated with an air dam? You don't know, nor do I. Which is why aero can't be considered. So, no to 2.
Again, un quantifiable, and impossible to be consistent. So, no to 3.
None of those are process considerations.

So, IF we accept 'known power". (And the ITAC better be consistent on this) the weight is 2600. Down 40.
Now the Golf is known to be 50 high due to the beam axle gift. Remove that, and the "new" car and the "old" car just got 90lbs closer.

I just don't see a need to rebuild ITB.

 

[lateapex911]

there are too many old volvos to keep track of. my notes from the last meeting indicate all discussion around moving *Volvos* to ITC were around the 240.

i think jeff just had a little brain fart. to my knowledge moving the 142 to C isn't currently on the table.

Oh, just WAIT until you start discussing Hondas! Your brain will split over the Civics!

"Oh, the rounded rear Civic?"
"No, the squarer back one"
"Ah, yes, it had a 120 hp engine"
"No, that one had the G67 C engine, it's 120, this is the G67 F engine with 119. COMPLETELY different cylinder head."
"Oh, yea, it's called the TX"
"No, that nomenclature was used in the 4th generation for a year, but it was part of the WX series."

There are only like 15 generations of Civics, in 5 different body styles with 8 different alphagram models, and elenvty billion different alphabet soup with numbers thrown in engine designations, LOL

 

[Knestis]

there are too many old volvos to keep track of. my notes from the last meeting indicate all discussion around moving *Volvos* to ITC were around the 240.

i think jeff just had a little brain fart. to my knowledge moving the 142 to C isn't currently on the table.

So someone is actually advocating that we completely restructure ITB around a new power-to-weight ratio, so the 240 will fit...??

REALLY...?

K

PS - Thanks, Gary!

 

[gran racing]

Just submitted my ITAC request about the multivalve engine default. Of course I included a typo requesting all cars use a gain of 35% (instead my intended 25% number). Josh will add a note to that though.

For any ITAC or CRB members following this thread, do not for one minute think that posting this process is a bad thing even when someone like me submits a request to have a part of it looked at. This is exactly what should be happening and is a huge leap forward in the way things are being done. Thank you!

 

[tnord]

So someone is actually advocating that we completely restructure ITB around a new power-to-weight ratio, so the 240 will fit...??

REALLY...?

K

PS - Thanks, Gary!

i'm not sure how you get to that conclusion from what i said.....but....yes.

 

[Knestis]

Discuss please.... If the new cars are competitive with existing cars, why is this such a downside?

For me two big concerns are the 18.84 ratio for ITC (and the implied weights for existing cars) and the apparent randomness in the difference between class ratios.
ITR->ITS Gap: 1.65
ITS->ITA Gap: 1.6
ITA->ITB Gap: 2.5
ITB -> ITC Gap: 1.4

At least to me, there appears to be no rhyme or reason to the step increases.

Sorry - don't want this to get lost because it's an important historical reference.

Those numbers ended up where they are NOT by some grandiose mathematical scheme. The got picked to align with the make/model options that defined the pointy end of the grid for each class - qualitatively and from anecdotal observation of on-track performance.

A got realigned against the CRX. B got oriented around the Golf II, 2002, and Volvo. S got indexed to the expectations placed on the choked-down e36 BMW 325.

This is pertinent to more conversations than just this one, I expect...

K

 

[Knestis]

i'm not sure how you get to that conclusion from what i said.....but....yes.

Sorry - I got that from Jeff's post about choices. Fix the [whatever Volvo] or address the ITB multiplier to "fix the class." Others seem to be advocating for the latter (e.g., Jeff J.) as well.

K

 

[pfcs]

Travis & ...

"anybody that wants to get all in a huff about process or "known output" figures being off by a few read that paragraph again. DIN horsepower is a measure i've never even heard used in my lifetime. a Stuksa brake? i assume that's some sort of dyno like a jet with a big drum and brake used to measure power? how does that compare to a jet number? does anyone have the foggiest idea? "

DIN is a set of engineering standards originally German but used by many (most) European manufactures to specify everything from S/N (signal to noise ratio) to engine power. Later European cars are often now rated in kW (kilowatts)
Stucksa is an american manufacturer based in Denver.(stucksdyno.com) Started by Harry Stucksa forever ago, they manufacture they manufacture high quality water absortion dynamometers (brakes) for use in engine (crankshaft) dynamometers which are ever so much more accurate than any chassis or hub drive unit (which are great for comparing apples to apples, ie: the same car when air and temperature are corrected for as in finding gains in a specific vehicle; not so good to determine actual power/torque or to compare to other vehicles) In addition to being well maintained and calibrated, Bob's dyno room is properly engineered with a large exhaust labyrinth (a small person could crawl his way out) and proper ventilation to preserve airflow through the bay while maintaining ambient temp and pressure and fresh air to the intake system of the engine under study. Bob's been running one of these 40 years and knows how to seperate the bullshit from the myths. Many johnny-come-lately "experts" with their chassis units either are clueless or so FOS their eyes are brown!