Improve 1/8 mile et

[82TwoHeadlight]

Summarized in the title. I'd like to increase the et of this truck from 7.70 to 7.50.

As the truck sits today it runs consistent 7.70 at 90 mph.

The local 1/8th mile has a 7.50 index truck class with a sizable purse.

I'd like to compete in the 7.50 truck class.

This past Friday I went to the test and tune and paid close attention to the trucks tuning for that class and was fortunate enough to line up with one. I'd estimate based on my run that 7.50 index truck must have run exactly 7.50.

My questions are:
Is the class going to be full of competitors running 7.5x?
Are they really that good or was it just the luck for the run I witnessed?
How could I get another 2 tenths for my truck and keep it consistent?

Based on what I saw i don't think I'd be competitive bringing a 7.70 truck to a 7.50 race.

For additional context, the track doesn't show times or include competitors time slips when you complete the run so I really don't know what et everyone is running.

 

[82TwoHeadlight]

I just realized more details on the current configuration of the truck will be needed:

Big block
Afr heads
236 degrees intake duration at .050
Th400 2500 Hughes stall
4.11 locker
295 MT drag radials

 

[JKRamsey1991]

Have you thought of rear gear swap? Most 1/8 mile guys I know run like 4.56 or 4.88s even. Whats your RPM at the top of the track?

 

[Hunter79764]

Gears and/or tires for consistent traction would be helpful towards your goal, I'd guess. Any rule restrictions on nitrous? might be able to tune your tenth's gains with that.

 

[82TwoHeadlight]

RPMs are relatively low in 3rd gear at the end of the track. Relatively zero tire spin with the 295 drag radials.

Based on these responses I could try a higher numeric gear ratio or nitrous. No restrictions on nitrous in the 7.5 truck class. The restrictions are 295 tire or smaller and no trans brake or electronics. I'm not sure what the "no electronics" means but I assume it's some type of delay box or something that automatically adjusts reaction time.
How much nitrous would be needed for 2 tenths? I remember ages ago there was a rule of thumb 10 hp= 1 tenth of a second. Does that apply to the 1/8 mile?
I beginning to think I'm at the stage of consideration where I may need to just try and see. I think the smallest nitrous kits are only 50hp? There must be a way to tune it down from there with a smaller nitrous jet, or maybe delay the hit until third gear shift?
What are your thoughts?

 

[PrairieDrifter]

Yep a delayed 50 shot would probably be a good starting point. They may make smaller jets, but running nitrous would be kinda pointless for a 20 shot lol. Just do a delayed shot. Fun factor as well over just regearing. Other than the inherent mechanical danger nitrous comes with.

 

[WesN]

What are your 60’ times. Being on the high end of a bracket is not always a bad thing unless it is heads up racing. You leave first and the other guy has to wait and that wait can mess with people and they can red light or cut a slow light.

 

[410 John]

I would try gears. Do you drive it on the street enough to care about drivability?

 

[Hunter79764]

Still think gears would be the "right" choice given what you said on RPM etc, but may take a hit on other stuff like highway cruise or general drivability for how you drive it. But yeah, some small jets you should be able to tune to get what you want. Do an RPM based trip maybe, that gives you another tuning option. And yeah, they make dry kits down to 20 hp or so (Sneaky Pete kit comes to mind, no direct experience though). That's probably the best use of nitrous in my opinion, trying to get a couple tenths for class rules. Other than just for fun, of course. Make sure you tune it right, though. 10 or 20 hp is probably fine as is if you aren't borderline lean already, but there will be a point where extra fuel is absolutely required if you want it to live repeatedly.

 

[Rustisbest]

More converter stall.
Higher gears and run it out in 2nd.

 

[Rusty Nail]

RPMs are relatively low in 3rd gear at the end of the track.

It's that shift that's killin your time.
Eat fewer Twinkies and go 4.56.
4.56 wins drag races. Ain't no reason to be in third gear in an 8th mile.

You can do it!

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[Catbox]

They used to say that 100 pounds equals a tenth.

How much does the truck weigh?
What can you pull off it when going to the strip?

Spare tire?
Tools?
Hood?
Bumpers?
Tailgate?
Change bench seat to lighter poly seats.

These are all cheaper than a gear change.
I bet that would get you closer to being a consistent 7.5X truck.

Even aluminum wheels would help.

Oh and we like pictures here.
More help will be provided upon your delivery of the standard internet currency of photos of said truck...

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[82TwoHeadlight]

Ok. I am trying to post photos but the images won't attach.

 

[Ricko1966]

Do you already have it timed and jetted for most mph in the trap.if not you can probably get your 2/10ths right there lose a few pounds off the truck,get some cold air to the airfilter,play with shift points and tune for fastest trap. Done.

 

[82TwoHeadlight]

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