Nov '12 Prelim Minutes & Tech Bulletin

[StephenB]

dyno info was submitted (and more was solicited) showing only ~20% gains but inconclusive to the peak, so we reran it at 25%.

there are only 2 of these running currently that I'm aware of.

so this data was from 10/10ths builds?

Stephen

PS: Dave your Car is MUCH faster than the "old" ITB. But then again ITB is now really the old ITA so I see why your upset.

[Chip42]

so this data was from 10/10ths builds?

Stephen

PS: Dave your Car is MUCH faster than the "old" ITB. But then again ITB is now really the old ITA so I see why your upset.

3 builds: 2 pre open ECU days but known to have been running APEXi EFI mods in the wiring under dash, the 3rd with a an MS2 and I know who did the work and trust that it's as close to 10/10ths motor as we are likely to see, especially since we buffered with 5% beyond what we see on the dyno. all agreed on WHP.

[StephenB]

Thanks. Are you able to share target info? Knowing the data on the crb's car would be interesting since that would give me a realistic goal to get to. I ran with his pre ecu car and it was faster than the norm back then. If not I understand.

Stephen.

[Chip42]

Thanks. Are you able to share target info? Knowing the data on the crb's car would be interesting since that would give me a realistic goal to get to. I ran with his pre ecu car and it was faster than the norm back then. If not I understand.

Stephen.

sure = 2550 classification, 25% gain, so working backwards is (2550-50(SLA))/(17*0.98) = 150 hp. assume ~127 whp target. 20% over stock is roughly what we saw, though.

[tom91ita]

... dave, we all know that prelude is effectively the same engine and should be treated the same way. write us a letter. or don't, if you are tired of seeing changes.....

Dave,

be very, very careful here. if they deem your motor as being "effectively the same engine" then you are likely to gain 100 #'s to the 2550 same as the accord. because if your motor is "the same" then we need to start with the same stock HP as the accord.

i maintain that your motor has a "similar" design. the lower CR (8.8 vs. 9.3) means that your 0.5 bump only gets you to be "effectively the same" as the accord is stock.

Chip,

i am not really that upset but i want to make sure that i am understanding the design differences in the Honda family of 1986 vintage fuel injected motors that would result in the dyno readings. you inferred at RRAX that there is good data on the 1986 crx si motor that supports the 1.3.

i am not disputing that right now since i do not have any dyno readings for a full built motor of my vintage. but as an engineer, i would like to know the design differences that give my motor so much more mojo gain per liter than the accord/prelude 2.0 L.

my issue with the dynos is that these could be manipulated if one is so inclined. both up or down. both by an engine builder or a competitor.

WOW! look at the big HP numbers i generated, pay me big $$! WOW! look at the low HP numbers i generated, i need a lower factor!

i see the similar engine design and the dyno results as both being data points that should be considered.

tom

[tom91ita]

....2 pre open ECU days but known to have been running APEXi EFI mods in the wiring under dash, .....

Chip,

i am not familar with APEXi mods in the pre ECU days.

were those acceptable per the rules of the day?

tom

[Rabbit05]

my issue with the dynos is that these could be manipulated if one is so inclined. both up or down. both by an engine builder or a competitor.

WOW! look at the big HP numbers i generated, pay me big $$! WOW! look at the low HP numbers i generated, i need a lower factor!

i see the similar engine design and the dyno results as both being data points that should be considered.

This is why I have not bothered to take the Audi to the dyno shop down the street from me....even I go spend the money to go dyno my car, and turn this info over to the powers that be . They can say ,"we dont trust your numbers , now go pound sand"...

Like what Dave said , what kind of politics are being played behind closed doors to push this through ?


I like Chris S's idea...and I was just perusing the Prod rules yesterday too...sounds like a decent alternative to go play there.

( and I am still waiting to see the "secret Audi HP info" that is not for SCCA members to see...)

[Rabbit05]

sure = 2550 classification, 25% gain, so working backwards is (2550-50(SLA))/17 = 147 hp. assume ~125 whp target. 20% over stock is roughly what we saw, though



Chip,
So just so I am not confused, 125 hp is the number you used to get to 2550 lbs ?

-John

[Chip42]

No, 25% over oem hp. Straight math.

[tom91ita]

John,

as i understand the process (mostly from memory)

Accord would be 120 HP stock * 17 pounds per hp * 1.25 (estimated gains with IT mods) + 50 (double wishbone suspension) - 50 (Front wheel drive deduct) = 2550 #'s

with the previously "default" 1.30 factor for ITB multi-valve motors, 2652 #'s so say 2650 #'s.

i believe i was treated rather fairly when the 86 crx si was re-ran. i went from a factor of ~1.41 to 1.3 when others got the 1.3 ITB multivalve factor. the car went from 2130 to 1970. one reason i think it was fair is that the 1.41 factor was quite close to what the 16V hondas had for a factor

i am just asking questions now because the accord engine and crx engine in stock form both have specific outputs of 61.4 (120/1.955) and 61.2 HP/liter (91/1.488), respectively.

for the prelude, the comment is the motors are similar and about the same. but for my car, it is not a similar design yet the specific outputs are...

sort of like Danny Glover in Dirty Harry, "i gots to know"

respectfully,

tom

[Rabbit05]

No, 25% over oem hp. Straight math.

Ahhh...thank you .



And thank you Tom for the detailed formula. I forgot what it was..

[Chip42]

W

Chip,

i am not familar with APEXi mods in the pre ECU days.

were those acceptable per the rules of the day?

tom

No, and I only know for a fact that one of those cars had it, and cannot say when it was added vs. When ecu rules openned up. The car in question had a stock ecu. The sister car I assume had the same setup, alas its been dead for a while now.
That does improve stock control of fuel somewhat, though, inching towards what might be seen with a real programable ecu controlling things. That the output agreed with a car running a pretty trick ms2 setup tells me fuel contol is sorted well enough for peak power determinations. Point is that, barring possible mechanical items, the cars appear close enough to peak to justify a 5% buffer.

Tom, there could be a number of differences. The objective is to consider the motors seperately, not using some sort of time/manufacturer/configuration data to make prediction, even if they are well founded. The prelude and accord have the same engine code, with some minor differences. That's a lot closer than a motor 25% smaller that simply shares some design concepts.

[Flyinglizard]

RE splitters/airdams/vortex generators
None of the above will make more than the equivalent of 10# in the car, within the IT rules of the body shadow.
The ITAC should also address the vortex generators, at the same time.
Pretty much any aircontrol with the lower edge 2in or more from the pavement, and inside of the body shadow, will have little or neg results.
The lift/downforce is made by moving air vertically. The bumper stops the upward flow on most of these IT cars. The exceptions are the Miata, MG rubber bumper, MR2.
The upward flow hits the bottom of the hood, the bumper,etc.
The only airdam with splitter that I have seen show a drag improvement , is snow plow shaped with a 3in slitter. Extended at least 6 in in front of the bumper, with provisions for the air to pass over the bumper without hitting the hood bottom. Not easily done with any of the IT rules. The ITAC is wasting it's time, as long as the rule stays inside of the body shadow.
If you can attach the air dam to the front bumper edge, than you can gain some. But the way I read the IT rules, if you can see the airdam edge from above, it is not legal . Maybe this needs some clarifying.
There is also a chance for gain by blowing the nose pressure out around the front tires. VGs and a small splitter can aid this flow. I have not seen a big drag reduction here either.

[Chip42]

mike,

pressure differentials matter. even if they do not result in downforce, you can use a splitter to enhance cooling flow through the radiator, reduce drag, etc...
they are being used because they work, NOT because they look cool. some guys SWEAR by basic air dams, too. the questions are "are they allowed" and "where can the supports be located" not "how much downforce will it generate."

[CRallo]

It says that it(whatever you happen to call it) must be attached to the body, but not ONLY the body. So where is the confusion about mounting?

And why ban limited production OEM stuff if you can make/buy custom? I never understood that.

[Flyinglizard]

I was trying to imply that the only rule needed is the shadow rule.
Mounting rules bother some cars more than others and are really not needed as long as the entire air control devices are covered by the body shadow rule.

[Andy Bettencourt]

It says that it(whatever you happen to call it) must be attached to the body, but not ONLY the body. So where is the confusion about mounting?

Agreed. So long as the mounting doesn't do something illegal, I don't get the issue.

[Andy Bettencourt]

And I am not understanding the Accord bitching. We all know how we got here and nobody has to like it - but here is the net result:

All ITB cars processed at 25%, 30% multi-valve boner gone
MR2 finally gets it's dyno data read and approved at a lower %

If the MKII VW's can make 25% over stock, they are fine. If they can't, send in the data.

[Chip42]

And I am not understanding the Accord bitching. We all know how we got here and nobody has to like it - but here is the net result:

All ITB cars processed at 25%, 30% multi-valve boner gone
MR2 finally gets it's dyno data read and approved at a lower %

If the MKII VW's can make 25% over stock, they are fine. If they can't, send in the data.

I'm pretty sure the A2s are run @ 30%, thus their gripe. I've said it a million times - data changes things, griping just makes people disinterested.

[tom91ita]

,.... The objective is to consider the motors seperately, not using some sort of time/manufacturer/configuration data to make prediction, even if they are well founded. The prelude and accord have the same engine code, with some minor differences. That's a lot closer than a motor 25% smaller that simply shares some design concepts.

understood. thanks.