ITB - what a bunch of crap

Well, Kirk posted that there IS an adder for TQ and that the process assumes struts.
And if the TQ adder is not there, it needs to be.

So... you are saying that struts are -50 and A Arms are +50???
So a 100lb delta for A arms in a class were cars are typically in the 100 to 120hp range?

Uhhh... I think my math, based on Kirk's post, is better.
Just sayin'.

Scott, who thinks its easy and we are making it hard.
 
Last edited:
Just for giggles and since it just won the ARRC, lets run an Accord LXi:

110x1.35x17=2525
-50 (fwd)
+50 (tq)
+50 (A Arms)
That gives us 2575lbs. Actually darned close to its current 2550 spec weight.
 
Catch22 said:
Well, Kirk posted they there IS an adder for TQ and that the process assumes struts. I'd quote it but its just one page back.
And if the TQ adder is not there, it needs to be.

So... you are saying that struts are -50 and A Arms are +50???
So a 100lb delta for A arms in a class were cars are typically in the 100 to 120hp range?

Uhhh... I think my math, based on Kirk's post, is better.
Just sayin'.

Scott, who thinks its easy and we are making it hard.
Click to expand...

Focus young Jedi.

There IS a potential adder for torque. Not for the G3 in it's process however. The process also assumes struts. This car has a BEAM rear.

Double wishbone is +50. So if two cars had the same 115hp motor for ITB, one a RWD DW car and one a FWD strut car, there would be a 100lb difference in their spec weight.

For you paying attention: The 1.6L Miata could EASILY be listed at 2515 in ITB using the 'process'.
 
Knestis said:
To that are added or subtracted a very limited number of incremental amounts for specific mechanical attributes - FWD gets a minus weight (50 or 100), brakes a plus or minus (50, but that's been applied pretty rarely), suspension (+50 for A-arms, the base presumes struts; -50 for "bad designs"), gear ratios (I don't think I've seen that in my time on the ITAC yet), and "other" - which as far as I know is mid-engine layout or good/lousy torque).
Click to expand...

Quoted from page 14 for reference.
 
Andy Bettencourt said:
What is your point? TQ is an adder, just not on the Golf III.
Click to expand...

Which is why I just added it to the Accord above.
I'm not following you Andy. Whats YOUR point.

I simply took Kirk's post and applied it to some cars. If you are telling me my math is wrong, then you are telling me Kirk gave us poor guidance.

Do YOUR process on the A3 for us and explain WHY you do what you do with it. Please explain why a 2.0 liter car in a class with cars with as little as 1.3 and 1.5 liters doesn't get that TQ adder? Why is it there if its not used?

PS - When you put that Miata in ITB at that weight did you give it a 35% adder?
Just askin'.
 
Catch22 said:
Which is why I just added it to the Accord above.
I'm not following you Andy. Whats YOUR point.

I simply took Kirk's post and applied it to some cars. If you are telling me my math is wrong, then you are telling me Kirk gave us poor guidance.

Do YOUR process on the A3 for us and explain WHY you do what you do with it. Please explain why a 2.0 liter car in a class with cars with as little as 1.3 and 1.5 liters doesn't get that TQ adder? Why is it there if its not used?

PS - When you put that Miata in ITB at that weight did you give it a 35% adder?
Just askin'.
Click to expand...

My point is that just because it's there doesn't mean it gets used on every car. That's why the last part of the process is subjective. I can cite just as many 2.2's, 2.3's, and 2.5's in ITB that make the 2.0 seem 'average' in size.

Nope on the Miata. 25%. It's an excersize in what could result if you just let the numbers fall where they may to continue to illustrate the point that this is a stupid excersize on a BB. These things have to be hashed out, discussed and agreed upon. I am not telling you Kirk gave you poor guidance, I am telling you that you did not apply the process in the same fashion as the ITAC did.
 
When is a 1.25 vs a 1.35 multipler used? Scott, you used 1.35 for Hondas but know I certainly can't get that out of my A20A3 engine after a full build. Also, when is the torque adder used?

(Scott, there are actually two engines with the Accords. One has a base of 110 and the other 120 hp.)
 
gran racing said:
When is a 1.25 vs a 1.35 multipler used? Scott, you used 1.35 for Hondas but know I certainly can't get that out of my A20A3 engine after a full build. Also, when is the torque adder used?

(Scott, there are actually two engines with the Accords. One has a base of 110 and the other 120 hp.)
Click to expand...

Dave - what front suspension does your car have????? And what is the BEST whp you are telling us the 110hp 2.0L in your car can make? Whay do your dyno sheets show?
 
Last edited:
i only pay attention sometimes.
if the process is the same for all then so be it. if they selectively slow down cars then that is nuts. if the weight is not correct then why pay attention to weight anyway.
 
I understand what you are saying now Andy.

And I'll go back to my original point of "just fix it then."

If the TQ adder wasn't used... Use it. There is certainly justification for that with that car. Cars with even BIGGER motors... Use the adder. THATS WHAT IT'S THERE FOR!!!

And BTW - The Miata could only "easily" be listed in ITB using the process if you apply the process incorrectly. But I guess maybe that was your point. I dunno.
At any rate, thats still no excuse for stagnation and fear of pushing ahead. Gotta break eggs to make an omelette as they say.
 
Catch22 said:
I understand what you are saying now Andy.

And I'll go back to my original point of "just fix it then."

If the TQ adder wasn't used... Use it. There is certainly justification for that with that car. Cars with even BIGGER motors... Use the adder. THATS WHAT IT'S THERE FOR!!!

And BTW - The Miata could only "easily" be listed in ITB using the process if you apply the process incorrectly. But I guess maybe that was your point. I dunno.
At any rate, thats still no excuse for stagnation and fear of pushing ahead. Gotta break eggs to make an omelette as they say.
Click to expand...

I am trying to 'just fix it'!

The point on the Miata is that it is clearly an ITA car...but when you look at it on paper, you could make a case it's an ITB car. A scrub-down of every car is neccessary.

I love omlettes.
 
i think that Torque may be a bit of a red herring. the ratio of torque to hp was quite close in a couple of earlier examples. if that ratio is close, the general process works.

if it is beyond some multiplier, then maybe you use it or correct.

but to state that my older honda can get 35% cause that is what hondas do is too general. that might be what a chipped OBD0 16 valve can get. but because hondas do well in ITA is not a reason to extend it to my OBD-Who 12 Valve.

but yes, sequential injection > dual point injection > carbs.
16V > 12V > 8V.
OBDx > vacuum advance.

But for simplicity sake, i think using HP covers many of the variables above.
 
Andy Bettencourt said:
The 1.6L Miata could EASILY be listed at 2515 in ITB using the 'process'.
Click to expand...

116x1.35x17=2660lbs

The Miata gets the 35% for the same reasons the Hondas do.
Really... Not that hard.

If you want to put the Miata in ITB at 2660lbs... Go right ahead.
 
Last edited:
tom91ita said:
but to state that my older honda can get 35% cause that is what hondas do is too general.
Click to expand...

Well, I actually used it because its a 12v MPFI motor.
But yeah, it can get 35%. Thats the outer limits, but its been done.

25% is reasonable on the VW 8v motors.
35% is reasonable on the 16v but dual point injected Civic DX.

The hard part is collecting the knowlege, especially with the older cars. But once you have that its pretty easy to take a very reasonable educated shot at it and get REALLY close in MOST cases.
There WILL always be outliers. I can't stress that enough. Nobody hits the target with every single shot.
 
Catch22 said:
116x1.35x17=2660lbs

The Miata gets the 35% for the same reasons the Hondas do.
Really... Not that hard.

If you want to put the Miata in ITB at 2660lbs... Go right ahead.
Click to expand...

Don't forget the +50 for A-Arms and possibly a hit for front "mid-engine"ness...

Hell, look at the 94-97 Miata in A.

128*1.35*14.5=2505+50 (A-Arms)=2555 in ITA

What's current spec weight for it? How about 2380.
 
Xian said:
Don't forget the +50 for A-Arms and possibly a hit for front "mid-engine"ness...

Hell, look at the 94-97 Miata in A.

128*1.35*14.5=2505+50 (A-Arms)=2555 in ITA

What's current spec weight for it? How about 2380.
Click to expand...

If you want to use singular dyno sheets, then all hell breaks loose. How about 2690 for the SE-R/NX2000?

Defining "When you KNOW something" is a hard thing to do as well. We can agree that the CRX power output is well known. How much information - and from how many sources do we need before it's 'fact'?

Sooooo many grey areas in this process guys...yet it is better than anything in any class right now. We can tighten it up, document what we did and run most of the cars through....but it still will generate issues no matter what.
 
Andy Bettencourt said:
If you want to use singular dyno sheets, then all hell breaks loose. How about 2690 for the SE-R/NX2000?

Defining "When you KNOW something" is a hard thing to do as well. We can agree that the CRX power output is well known. How much information - and from how many sources do we need before it's 'fact'?

Sooooo many grey areas in this process guys...yet it is better than anything in any class right now. We can tighten it up, document what we did and run most of the cars through....but it still will generate issues no matter what.
Click to expand...

Very true. I guess it's a little bit different for me since I'm coming from the standpoint of a car/chassis that was adjusted based on "When you KNOW something".

Are Miatae only making 25% gains or is it more like 30-35%? I know what I KNOW. :shrug:
 
Dave - what front suspension does your car have????? And what is the BEST whp you are telling us the 110hp 2.0L in your car can make? Whay do your dyno sheets show?
Click to expand...

Now sure why you feel compled to play games, but since you'll get your jollies from it the suspension on my car is a double wishbone and the rear uses transverse arms with conventional MacPherson struts.


Our goal after a full build (engine, tuning, tranny, yadda, yadda) for this car was 110 at the wheels. We got 112. Then again, according to you "if you want to use singular dyno sheets, then all hell breaks loose" so I'm not sure why you are asking. Oh, was that you way of replying on my previous question where I was curious how the gain % is determined?


Ready for the next riddle Andy.
 
Last edited:
Catch22 said:
Well, I actually used it because its a 12v MPFI motor.
But yeah, it can get 35%. Thats the outer limits, but its been done.

25% is reasonable on the VW 8v motors.
35% is reasonable on the 16v but dual point injected Civic DX.

The hard part is collecting the knowlege, especially with the older cars. But once you have that its pretty easy to take a very reasonable educated shot at it and get REALLY close in MOST cases.
There WILL always be outliers. I can't stress that enough. Nobody hits the target with every single shot.
Click to expand...


Quoted for truuf.

Now, look at Scott's ITB list.
There are cars there spanning what, 25 years? In that time, there has been a boatload of changes. To the methods of building cars, casting engine parts, rating hp from the factory, and on and on.

Then you have individual car differences, even from the same period. On one hand, we want to be generic, and apply multipliers based on the genre. Eg: 2 valve non OHC motor? 20%. 4 valve DOHC? 25%. Oh, but wait...that particular 2 valve motor, while it seems identical to the one made the year before, is a smogged up POS. So, if we apply the SAME multipler, whoops! Trouble! And so it goes.

So, we need to start with the basics, stick to it whenever possible, but fold in some specific situation knowledge.

I've been looking at ITB for over 6 months now, and I know if we just start readjusting cars based on the standard build gains, we're going to have some super light old cars...and they'll romp. Some don't make sense from a pure numbers point of view, but in reality, they're pretty close to where tey need to be.
 
You must log in or register to reply here.
Back
Top