SST MPH / Roll Bar Question

[DailyDriverSst]

Finally got my truck almost done. I did 1100 miles on Rocky Mountain Race Week 2.0 with a tune kind-of duct taped together on 8ish pounds of boost

4400 pounds with me in it
408 small block with F1A procharger
1.80 low Glide, 4.10 rear gear
275 M&H DOT radial
2-step 3000

60': 1.78
330': 4.96
660': 7.67 @ 91
1000': 9.99
1320': 11.95 @ 114

Since then, I've moved some weight around, mounted 28x9 radial slicks, added traction bars, and changed to a 1.98 low gear. Same 8 pounds of boost (really closer to 7 at 1/8 mile). I've also creeped the 2-step up to 3500.

So far, best 1/8 ET is:

60': 1.67 ___(+0.11)
330': 4.74 ___(+0.22)
660': 7.32 @ 95 ___(+0.35)

Right now i'm moving even more weight around and tweaking on the leaf springs/suspension. I'm thinking I might be able to get the 2-step up to 4,000 without getting into the converter.

What would this equate to in the 1/4 mile as things stand? Wallace calculator says 11.66 @ 117, but I'm curious on real numbers. Based on the incremental gains, I'm thinking 11.50's, MAYBE high 11.40's?


Now my real question: Once I get weight and power management under control and move up a blower pulley to 12 pounds of boost, I'm obviously trying to nail 7.00 index in the 1/8 and 10.90 in the 1/4.

How close to the 135 MPH barrier might I get? I want to only do a 5 point roll bar if I can. I'm optimistically thinking I probably won't surpass 125?

[Keith 944]

Originally Posted by DailyDriverSst

Finally got my truck almost done. I did 1100 miles on Rocky Mountain Race Week 2.0 with a tune kind-of duct taped together on 8ish pounds of boost

4400 pounds with me in it
408 small block with F1A procharger
1.80 low Glide, 4.10 rear gear
275 M&H DOT radial
2-step 3000

60': 1.78
330': 4.96
660': 7.67 @ 91
1000': 9.99
1320': 11.95 @ 114

Since then, I've moved some weight around, mounted 28x9 radial slicks, added traction bars, and changed to a 1.98 low gear. Same 8 pounds of boost (really closer to 7 at 1/8 mile). I've also creeped the 2-step up to 3500.

So far, best 1/8 ET is:

60': 1.67 ___(+0.11)
330': 4.74 ___(+0.22)
660': 7.32 @ 95 ___(+0.35)

Right now i'm moving even more weight around and tweaking on the leaf springs/suspension. I'm thinking I might be able to get the 2-step up to 4,000 without getting into the converter.

What would this equate to in the 1/4 mile as things stand? Wallace calculator says 11.66 @ 117, but I'm curious on real numbers. Based on the incremental gains, I'm thinking 11.50's, MAYBE high 11.40's?


Now my real question: Once I get weight and power management under control and move up a blower pulley to 12 pounds of boost, I'm obviously trying to nail 7.00 index in the 1/8 and 10.90 in the 1/4.

How close to the 135 MPH barrier might I get? I want to only do a 5 point roll bar if I can. I'm optimistically thinking I probably won't surpass 125?

You will be way under 135. 120-124 sounds about right and don’t forget the rollbar will add some weight right now my street /strip car can run around 1090s to 11.00 I will look at the numbers and get back to you

And I believe it’s 6.90 1/8 mile. 7.00 was old ihra index

[Tom Goldman]

Just my opinion ,but at over 4000 pounds a 5 point roll bar is not going to offer much protection in the event of a crash at 120 or for that matter any speed . A lot can happen on a 1/8 mile run , or after the finishline , especially on small tires .
You should definitely consider a cage . If street driving is a consideration, a 8.50 or slower cage can be built with removable side bars .

[Keith 944]

OK being I can’t post a picture I will write these out these are the numbers for a flat out pass in my 3800 pound three speed small block Chrysler 3.90 gears 8” ATI converter leaving @3000 footbreak on Hoosier 10x 28 dots @ 2800da
1.537
4.452
6.948
98.12mph
9.121
10.969
121.50mph

[Lenny5160]

On my door car, multiplying the 1/8 mile ET x 1.584 gets you the 1/4 mile time.

The factor is a little different for my dragster, but still very close.

I would imagine that a supercharged combo will run the back half harder, and also MPH well for the ET. The one complete run that you posted, the factor was 1.558. Applying that to your 7.32 nets a 11.404 in the 1/4.

In any case, I agree with Keith that you will likely be quite a ways from 135 in the 10.90 ET range.

[DailyDriverSst]

Glad i'm not too crazy. I was pretty sure 125ish would be about right but kept doubting myself.

I know going from 8psi to 12psi of boost will pick up alot, especially down low, assuming the converter doesn't eat it all up. But i'm still working alot of things out and have a long way to go on suspension - I still have a stock leaf pack and shackles.

I just ordered a set of Corbeau seats today to complement the rollbar going in. To Tom's credit, it's a heavy truck with C-clip axles and drum brakes indeed, but it's also all factory steel, so I'm trusting in the factory cab strength if something goes wrong.

Using my tax return on the seats and roll bar. Next winter's project will be a Ford 9" swap, aiming for the Dallas divisional of 2023 to get into S/St.

[Keith 944]

[QUOTE=DailyDriverSst;657547
But i'm still working alot of things out and have a long way to go on suspension - I still have a stock leaf pack and shackles.
Using my tax return on the seats and roll bar. Next winter's project will be a Ford 9" swap, aiming for the Dallas divisional of 2023 to get into S/St.[/QUOTE]



Street/strip go with the caltracs mono leaf, shocks, and bars. They work great!

[Lenny5160]

Originally Posted by Keith 944

Street/strip go with the caltracs mono leaf, shocks, and bars. They work great!

I would not accept a free backhalf job to replace my Caltrac bar/split monoleaf/radial tire combination.

Calvert didn't make/brand shocks yet when I put it all together, or I would probably have those too.