Weight Watchers
11-18-2012, 07:37 PM
#16
Rennlist Member
If that's the case, how come we see under 2mph difference in trap speed on the typical 70-125 straight when we "bolt in" a student.
Plus, in Spec 911, the winnera carry up to 150 lbs in trophy weight.......yet still win.
Plus, in Spec 911, the winnera carry up to 150 lbs in trophy weight.......yet still win.
11-18-2012, 08:49 PM
#18
Ok, that was snarky but I couldn't believe you said that given the history of every race vehicle trying to lighten or eliminate any excess weight.
In the instances you mentioned there are tons of variables, not jus weight...adhesion, driver skill etc.
Given two vehicles that are exactly the same, and the variable eliminated would not the lighter vehicle, say by 250 lbs or so, be quicker?
In the instances you mentioned there are tons of variables, not jus weight...adhesion, driver skill etc.
Given two vehicles that are exactly the same, and the variable eliminated would not the lighter vehicle, say by 250 lbs or so, be quicker?
11-18-2012, 09:29 PM
#19
Addict
Yesterday was a loosing day for weight loss. 
The bumperette delete is coming along nicely.
The smuggler's box lost some aluminum scrap, but I will retain the blower because I like the airflow. The front fan got removed and replaced with aluminum block-off plates. The one up against the bumper was a blast to make. The bends are not parallel with each other. Ya, got a bit messy with the RTV.
The bumperette delete is coming along nicely.
The smuggler's box lost some aluminum scrap, but I will retain the blower because I like the airflow. The front fan got removed and replaced with aluminum block-off plates. The one up against the bumper was a blast to make. The bends are not parallel with each other. Ya, got a bit messy with the RTV.
11-18-2012, 10:12 PM
#20
Looks good, I've retaned the front blower too. Dump the spare tire and jack/jack tools and get one of these
http://www.ebay.com/itm/CHEVROLET-GM...257#vi-content
My Caddy came with no spare and this fix flat air compressor....wouldn't trust my 30 year old spare anyway.
http://www.ebay.com/itm/CHEVROLET-GM...257#vi-content
My Caddy came with no spare and this fix flat air compressor....wouldn't trust my 30 year old spare anyway.
11-19-2012, 09:56 PM
#21
weighed it almost 'dry' today (fuel) @ 2450...getting there, still stuff to change out.
So folks won't think this is for speed...I'm doing this in support of Michelle Obama...
RIP Twinkies.
So folks won't think this is for speed...I'm doing this in support of Michelle Obama...
RIP Twinkies.
11-20-2012, 01:19 AM
#23
Rennlist Member
Ok, that was snarky but I couldn't believe you said that given the history of every race vehicle trying to lighten or eliminate any excess weight.
In the instances you mentioned there are tons of variables, not jus weight...adhesion, driver skill etc.
Given two vehicles that are exactly the same, and the variable eliminated would not the lighter vehicle, say by 250 lbs or so, be quicker?
In the instances you mentioned there are tons of variables, not jus weight...adhesion, driver skill etc.
Given two vehicles that are exactly the same, and the variable eliminated would not the lighter vehicle, say by 250 lbs or so, be quicker?
And that's only realized by looking at data after the fact. In the olden days, maybe you'd measure splits between sectors. I spent many a session doing that in the '80s (local to you @ PIR and Firebird when I was at ASU, then later when I opened my shop in Central Phoenix). Once we were able to get video in the cars (~20 years ago), you could read gauges between points to tell.
I don't have data logs on this laptop, but off the top of my head a pull from T15-T1 at Thunderhill (~75-~125) with a 3.0 Spec 911 (260 crank hp/2350 unballasted v. 2450 ballasted) gives about a 2mph trap speed and .5-.7 second ET difference over a ~12 sec run.
Couple of laps demonstrating what's close to Spec 911 with my faux 993RS v. an '07 GT3 of similar weight and ~100hp more:
11-20-2012, 03:13 AM
#24
Racer
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Yeah that seems about right Ken, whats the older drag racing saying 100 pounds= 1/10 a second, and I believe hot rod magazine has proved that a couple times... most conversions show that dropping 100 pounds is like gaining 10 hp
Also I'm pretty sure I'm required by law to support ASU alums!
Also I'm pretty sure I'm required by law to support ASU alums!
11-20-2012, 01:36 PM
#25
Let's assume a 2800 lbs car at start, and 210hp (I like nice numbers). That's 13.3 lbs/hp.
If you can get that same car down to 2400 lbs, you've now achieved 11.4 lbs/hp.
To achieve that same weight/power ratio but changing hp instead of weight, you would need 245hp. (2800lbs / 245hp = 11.4 lbs/hp).
So essentially, the OP's lightened car has similar weight/power to his original car with 35 more hp. Now, going one step further, 240hp is very doable with a 3.2 engine. Add in those engine mods and his 2400lbs, 240hp car achieves a very impressive 10lbs/hp.
EDIT: Sorry, just noticed OP's car is an SC. The above was done assuming a 3.2 - but the principle stands.
11-20-2012, 01:47 PM
#26
My *** dyno can tell the dif.....I have a nice neighbor Dave, big Cannuck that weighs in at 250 + pounds...no matter what car I have him in, Porsche or my hotrod I can def tell the dif when I bury the go pedal.
100 lbs = 10 hp....man, that's be nice if on target. Cheap HP indeed for a P car.
100 lbs = 10 hp....man, that's be nice if on target. Cheap HP indeed for a P car.
11-20-2012, 01:50 PM
#27
Rennlist Member
Not looking to argue, but rather to present another point of view for discussion:
Let's assume a 2800 lbs car at start, and 210hp (I like nice numbers). That's 13.3 lbs/hp.
If you can get that same car down to 2400 lbs, you've now achieved 11.4 lbs/hp.
To achieve that same weight/power ratio but changing hp instead of weight, you would need 245hp. (2800lbs / 245hp = 11.4 lbs/hp).
So essentially, the OP's lightened car has similar weight/power to his original car with 35 more hp. Now, going one step further, 240hp is very doable with a 3.2 engine. Add in those engine mods and his 2400lbs, 240hp car achieves a very impressive 10lbs/hp.
EDIT: Sorry, just noticed OP's car is an SC. The above was done assuming a 3.2 - but the principle stands.
Let's assume a 2800 lbs car at start, and 210hp (I like nice numbers). That's 13.3 lbs/hp.
If you can get that same car down to 2400 lbs, you've now achieved 11.4 lbs/hp.
To achieve that same weight/power ratio but changing hp instead of weight, you would need 245hp. (2800lbs / 245hp = 11.4 lbs/hp).
So essentially, the OP's lightened car has similar weight/power to his original car with 35 more hp. Now, going one step further, 240hp is very doable with a 3.2 engine. Add in those engine mods and his 2400lbs, 240hp car achieves a very impressive 10lbs/hp.
EDIT: Sorry, just noticed OP's car is an SC. The above was done assuming a 3.2 - but the principle stands.
11-21-2012, 04:10 AM
#28
Racer
Join Date: Apr 2012
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Not looking to argue, but rather to present another point of view for discussion:
Let's assume a 2800 lbs car at start, and 210hp (I like nice numbers). That's 13.3 lbs/hp.
If you can get that same car down to 2400 lbs, you've now achieved 11.4 lbs/hp.
To achieve that same weight/power ratio but changing hp instead of weight, you would need 245hp. (2800lbs / 245hp = 11.4 lbs/hp).
So essentially, the OP's lightened car has similar weight/power to his original car with 35 more hp. Now, going one step further, 240hp is very doable with a 3.2 engine. Add in those engine mods and his 2400lbs, 240hp car achieves a very impressive 10lbs/hp.
EDIT: Sorry, just noticed OP's car is an SC. The above was done assuming a 3.2 - but the principle stands.
Let's assume a 2800 lbs car at start, and 210hp (I like nice numbers). That's 13.3 lbs/hp.
If you can get that same car down to 2400 lbs, you've now achieved 11.4 lbs/hp.
To achieve that same weight/power ratio but changing hp instead of weight, you would need 245hp. (2800lbs / 245hp = 11.4 lbs/hp).
So essentially, the OP's lightened car has similar weight/power to his original car with 35 more hp. Now, going one step further, 240hp is very doable with a 3.2 engine. Add in those engine mods and his 2400lbs, 240hp car achieves a very impressive 10lbs/hp.
EDIT: Sorry, just noticed OP's car is an SC. The above was done assuming a 3.2 - but the principle stands.
which really isn't that much when you think about it, its not gonna turn your car into a lightening fast machine, the difference is going to be slightly noticeable at best, you can blow more the 4/10s on a bad shift alone, and A/C in Arizona is more important to me than the 1/10 a second i gain without it installed haha
11-21-2012, 03:02 PM
#29
yep and if you cut 400 pounds out of the car it would be roughly 4/10's faster to the 1/4 miles, and what Ken is showing via split times is rough .5-.7 seconds is translating to that weight lose
which really isn't that much when you think about it, its not gonna turn your car into a lightening fast machine, the difference is going to be slightly noticeable at best, you can blow more the 4/10s on a bad shift alone, and A/C in Arizona is more important to me than the 1/10 a second i gain without it installed haha
which really isn't that much when you think about it, its not gonna turn your car into a lightening fast machine, the difference is going to be slightly noticeable at best, you can blow more the 4/10s on a bad shift alone, and A/C in Arizona is more important to me than the 1/10 a second i gain without it installed haha