Budget 6.70 drag truck build!!

Ran a few test passes tonight. Finally got the trans brake working correctly . All night the truck felt down in power. Finally came to realize my afc wasn’t working as it should. I was dumb and forgot to tighten the preboost screw and the jam but and it vibrated out causing all the air pressure to afc to leak. was only probably getting 400ccs with the afc closed and not getting any boost. Egts on the data logger showed 950* peak. However still went w best 60 ft yet of 1.52. Hopefully we will keep improving. Truck would leave hard and lift the tire then fall on its face. Ran three passes all were between 7.12-7.127 mph was way down tho which is expected from the low amount of fuel. Ran 97-98 on each pass. And soemthing wasn’t happy in the charger and it decided to chirp pretty hard on the last pass. I’ll get it fixed and actually have the afc working again next week! Overall am happy tho. Trans is working amazing. The chassis seems like it’s gonna work great with some power!


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As you can hear in the video charger let go on that pass. Think it was something to do with not enough fuel to spin it hard enough. And with the pressure from the spray I believe it was putting pressure against the compressor wheel at a already slow shaft speed. Hopefully the wheel isn’t killed. But I’ll know tomorrow


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Few pics from over this weekend. Going to a very well prepped track and gonna see how it does with 800ccs!
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12valveblkcld said:
How'd she do?

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Ran 7.12-7.125 between 3 passes. But only had 370ccs of fuel. Had a afc problem and it stayed shut and never moved allowing more fuel. It is fixed now. Excited to see how it does with the correct fuel.


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Well after what I thought was a turbo failure was actually just where I pushed some oil out the valve cover and the inlet in the charger sucked it in. I guess the surging was from not enough fuel and slowing compressor wheel down with nitrous back pressure. It’s back together and already in the trailer ready for Friday. Will be getting a weight on it aswell as adding some more breathers tomorrow!


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Still had issues last week. However cut a personal best 60ft of 1.49 still learning as we go making a charger change this week and more testing this weekend! Also. Got a bump box on the way for the transbrake, so let’s see how that goes.

Also before last week got a weight on the truck it did gain alitle weight this off season. It’s now 3940 with a 270lb driver and full of fluids race ready. 59/41 weight offset


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I highly suggest lowering timing and seeing what it does. What pistons are in it? Really should work with higher rpms if it keeps falling off


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97rada said:
I highly suggest lowering timing and seeing what it does. What pistons are in it? Really should work with higher rpms if it keeps falling off


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I’ve talked with a few people who specialize in building chargers. All have told me the 88 in a 400 frame don’t work right unless shifting 5000+ which is on common rails, mine would be even harder plus up there I’m way past my power. I am dropping timing however and going down alittle on charger size. We shall see. Going to the event local to me this weekend to see how it does with the changes and more spray.


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You can make an 88 work. It’s not that hard. You could be on the wrong side of timing. To high and they fall off. Without being on a dyno and seeing what it does it’s Hard to tell. At 42* mine was still making power but the gains at peak were less. Even if it’s not making peak you can Still make good power shifting at 5000+ letting it shift down into peak power staying on the turbo.


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97rada said:
You can make an 88 work. It’s not that hard. You could be on the wrong side of timing. To high and they fall off. Without being on a dyno and seeing what it does it’s Hard to tell. At 42* mine was still making power but the gains at peak were less. Even if it’s not making peak you can Still make good power shifting at 5000+ letting it shift down into peak power staying on the turbo.


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We will see. I’m gonna try this other box charger and based on how it does with it will be deciding on how things go. You ran a 475/96/1.32 on the manifold last year didn’t you?


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Saw your vid you sent last night, safe to say going down to the 475 was a good move. Congrats, glad to see you making big improvements.
 
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