ET Estimates please

-
I built a 446 years ago with bowl ported Ede heads, 13:1, MP 620 cam, M1 with a 1050/4500 on it.
Made about 625hp on the dyno.

Went in a 3150lb race weight 71 Cuda back half car...... went 9.80’s.

Works out pretty close:

9D902FD5-9665-410A-B722-0A8BF38CB5C8.jpeg
 
PRH said:
I built a 446 years ago with bowl ported Ede heads, 13:1, MP 620 cam, M1 with a 1050/4500 on it.
Made about 625hp on the dyno.

Went in a 3150lb race weight 71 Cuda back half car...... went 9.80’s.

Works out pretty close:

View attachment 1715614038
Click to expand...


That dyno has to be modest. I now my car is heavier and the converter is killing my short times and the gearing is about 1,000RPM off but 600hp, 3450 with me in it, 10.98@124. HArd to believe there is a almost a second more in the car.
 
The pic in your Avatar looks like LVD........is that where you normally go?

Is that where you ran the “10” a couple weekends ago?

That dyno has to be modest
Click to expand...

My experience has been that most peoples cars/combo leave quite a bit of ET on the table.
Especially any type of “street/strip” combo.
 
My car is strictly a race car and has gone 10.48 at 130. 3500 lbs. I’m at 600hp so maybe not that far off. He’s only 3150 and another 25hp and probably set up better.
 
PRH said:
The pic in your Avatar looks like LVD........is that where you normally go?

Is that where you ran the “10” a couple weekends ago?



My experience has been that most peoples cars/combo leave quite a bit of ET on the table.
Especially any type of “street/strip” combo.
Click to expand...

Yes, I race at LVD. Are you from the area?

I know there is more in mine. With a 1.67 short leaving at 1100rpm, that tells me I definitely have 2 tenths on the big end. I don't know how much another 1,000 rpm at the traps is worth but i'm fixing to find out
 
roccodart440 said:
Yes, I race at LVD. Are you from the area?
Click to expand...

Okay, so forgetting about the actual dyno number.......
How much difference in power would you expect to see between your motor, as it is now, and a 10.7:1 stock stroke 383 with unported 906’s, .560 lift solid cam, an RPM intake and Hooker Competition headers...... with both motors being tested back to back at the same dyno, on the same day?

What was the date you went in the 10’s there?
I think one of my friends was running there that weekend.
 
PRH said:
Okay, so forgetting about the actual dyno number.......
How much difference in power would you expect to see between your motor, as it is now, and a 10.7:1 stock stroke 383 with unported 906’s, .560 lift solid cam, an RPM intake and Hooker Competition headers...... with both motors being tested back to back at the same dyno, on the same day?

What was the date you went in the 10’s there?
I think one of my friends was running there that weekend.
Click to expand...

I'd guess 150 -200 hp difference.

Sunday the 4th I believe. NETO was there.
 
I'd guess 150 -200 hp difference.
Click to expand...

Okay........ so we’ll use the Moroso chart to gauge the HP difference to see how close it comes to that.

On the Moroso chart your speed shows a fair amount better HP than the ET.
At 3450lbs the ET shows 463hp, and the 124mph speed shows 506hp.

At the same track, my car went 11.40@115 and change, at 3670lbs, weighed on their scale that day.
My car shows the same HP for both speed and ET..... 432hp.

So, based on ET...... you’re showing 32hp more than my 383....... and based on speed you’re showing 74hp more.

My “rule of thumb” for a street/strip car that’s set up at least “close” to being correct is........ it should be able to run within 10% of the STP dyno numbers, according to the Moroso chart.
This would be for tracks that don’t have altitude corrections.

My 383 dynoed at 485hp, so on that day, at that track, I was right at about 90%.
Based on 600hp STP, you were at 77% for ET, and 84% for speed.

At another track, on a better day....... that exact same combo in my car went 11.26@119, which shows 93% for ET and 98% on speed.

I have several customers who have run very close to 100% according to the Moroso chart........ but there are also many that are well outside “the 90% rule”.

My friends Stocker is well over 100% in any kind of 1/2 way decent air.
 
So my car should have 6 to 13% left in it then?

That's 10.32 - 9.50

10.32 might be believable. I can definitely see at least a 10.70 with the converter change.

My trap speed and RPM is 124mph/5300. That's with a final gear ratio of 3.55:1 (3.6)

My guess is trapping at 6200-6300 will make a substantial difference too.
 
So my car should have 6 to 13% left in it then?

That's 10.32 - 9.50
Click to expand...

I’m not sure where you’re getting the 9.50 from, that shows 750hp@3450lbs.

What I’m saying is, the “90%” point for 3450lbs and 600hp, based on ET and Speed is [email protected](that’s what the performance potential is for 90% of 600hp(540)@3450lbs).
With the right converter & gearing, provided it hooked like it should...... it should be able to put up those numbers.
That would be the equivalent performance to my car running the [email protected](both showing 90%).

I just talked to my friend who was there on the 4th.
He bought a used motor a couple of months ago and had it on the dyno before putting it in the car.
It made 728hp.
At LVD on the 4th at 1:29pm, the weather, according to his weather station was 29.54” baro, 57.7*, 54.5%, DA of 572’(DA showing better than actual track elevation).
That day on the scales there it weighed 2915lbs.
It went [email protected]........ which shows 725hp(99.5%) for ET, and 695hp(95.5%) for speed.

A few hours earlier in the day it went [email protected].
The previous day it ran a number of 9.10’s and one 9.08.
 
Last edited:
roccodart440 said:
So my car should have 6 to 13% left in it then?

That's 10.32 - 9.50

10.32 might be believable. I can definitely see at least a 10.70 with the converter change.

My trap speed and RPM is 124mph/5300. That's with a final gear ratio of 3.55:1 (3.6)

My guess is trapping at 6200-6300 will make a substantial difference too.
Click to expand...
Rocco, I say there is room for improvement but how much you gain is one thing, how much you gain against the calculator is another. Ether way, if your going to try and attempt to do so, first, just simply stated, good luck and have fun while doing so, but more importantly, do t loose sleep over what the calcs say it should. Just get what you can get. Keep hammering away at it.

Remember, when it’s not fun anymore, your doing something wrong. ;)
 
wally said:
Good morning Bob. I agree that he should have no problem hitting low 10's , maybe high 9's.
Glad to see you had the car out. I could only get out once this year.
I hope all is well with you and family... stay safe hope to see you soon. Steve
Click to expand...
Good to hear from you! Saw you make a few laps too, but never got over to talk. Next time I see you out i'll make a point of it to say hi.
 
6 days, 23 hours, 59 minutes and 59 seconds.
 
So....he finally made it back out and the car did a burnout and quit and wouldnt crank over again. So they loaded it up and took it home...where it still sits. And my bad, they arent 240's, they are Edelbrock Performers with the 210cc runners (he has a set of 240;s but hes saving them for future use). INtake is a Victor manifold. I have a hard time believing the car weighs more then 2700 lbs after looking at it. The car in my avatar weighed 2985 at Norwalk with glass hood, decklid, bumpers, doors, dash, a Dana, iron heads, original front/rear glass and factory k member. His car has tubular k member and no inner fenders and I believe lexan all around. I would think it would be 2 tenths quicker then mine just in weight alone.
 
You must log in or register to reply here.
-

Back
Top