A buddy just removed 218# off his car. It ran a best of 4.95.Wondering what it should pickup in 1/8 just from weight change so as to judge what other changes do.Switched from gas to methanol at same time and cpl things in motor. So what your best SWAG?

This message has been edited. Last edited by: wideopen231,

100lb went from 4.80 to 4.72 in my car within 30 min. All in the driver’s seat lol.

What did it run before the changes?
How about listing ALL the changes.

stephens numbers are a good reference

As stated it ran 4.95 before. That was with stock motor,smaller turbo and on gas.As for changes they will be harder to figure on since its a turbo VR-6. He has changed the turbo gone to bigger cams .mechanical pump instead of electric,changed heads,reworked sheet metal intake and as stated switch to methanol.

If he would have left it all the same except for the weight change, it should go about 4.82. After a bunch of other changes who knows until he runs it. Changing a lot of things at once he might backup a lot. Hopefully not. I like to change 1 thing at the time, so if it falls off I know were to go.

This message has been edited. Last edited by: Footloose,

What's the starting weight?
Got a dyno sheet? Time slip?
Maybe a data log of a decent run?
Rear tire size? Rollout?
Got plenty of time now that I'm furloughed for 2 weeks so I can model the car in Quarter Pro.

Taking a swag, if the car originally weighed 2500, then a 2282lb car could go 15 quicker.

quote:

Originally posted by Footloose:
If he would have left it all the same except for the weight change, it should go about 5.82. After a bunch of other changes who knows until he runs it. Changing a lot of things at once he might backup a lot. Hopefully not. I like to change 1 thing at the time, so if it falls off I know were to go.

Agree

Cory and I are 85 to 90 lbs apart...6 to 7 hundreds in the 1/8...I gotta lose weight in the belt (gut) area. or he could use to gain a few lbs...

I will guess 4.74 on methanol vs gas at 4.79...

Meant 4.82 not 5.82

quote:

Originally posted by Footloose:
Meant 4.82 not 5.82

I figured guess my eyes are not only ones that get blurry after few minutes on computer.

Door car or dragster? What weight before and after? I think the amount of HP will play a roll as well and style of car as to what he picks up just from weight. FWIW my Stratus has gained 88lbs since we first brought it out. It really has not changed ET much at all, .03-.04 tops. But this is a 2330lbs car that makes 1200ish

Thanks guys. From what cpl have posted Al,Chris and footloose. It seems my guess was pretty close. I figured .15 to .17.

Not dismissing question on car just lot of variables with changes made to cover in less than short bedtime story.LOL

90# in driver weight was .09 in 1/8 mile et. We could not believe it so we had to do it again the next week. Still .09 !

quote:

Originally posted by 27Keith:
90# in driver weight was .09 in 1/8 mile et. We could not believe it so we had to do it again the next week. Still .09 !

Not doubting your results. From what I have learned from others its rare for the 100=.1 to work in 1/8,which stands to reason.Then most of your et gains are in 1st half of track. We gained a bunch with TA/FC and 90% of it in 1st 1/4 of track.
Maybe you just stumbled across a better balance on car along with weight reduction. Hey if it picks up like that he will be overly full of happy ****,already pretty full anyway.

We could even see a small difference in the converter stall. 60 ft was quicker also. If memory is right it was only .5 mph so your theory on most gains in front half of the track hold true.
The reason we did this was my buddy had to work , so I ran a tt for him to get the car warmed up. 1st rd we only dialed .07 quicker cause we didnt know. His opponent redlit and he went .02 under or .09 quicker.

Dragsters to Door Cars is different.