[Joshinator99]

Originally Posted by KingLT1

Not sure if it's the track but your ET seems slow for the MPH. A 1.5 60ft with 148 mph trap should be somewhere around a 9.5 pass.

Something odd is happening in the front half. I would expect your trap to be 118-119 in the 1/8 if your trap is 148 in the 1/4. The 32-33mph back half gain kind of supports that theory.

Not sure if you have some trans tm stuff at play here?

If I’m being honest, the track is kind of crappy. Prep is not great. But, you’re probably right about the trans tune too. I’ll take that conversation to PM with you.

I think I’m going to start a discussion in the drag strip forum about hooking in the 8/9 second range too… think that will be a good conversation.

[Joshinator99]

So the recent dyno visit showed that my new pulley combo (8.00/2.85) is causing belt slip, even with the 10-rib belt drive and upper griptec pulley. I would very sporadically see 19 PSI but would then go back to 16. So I’m not seeing any gain. I need more belt wrap so I decided to go with a bigger lower which will allow me to use a bigger upper too. I ordered up one of TooHighPSI’s 9.25” lower pulleys assuming it would work and it looks like a direct fit when compared side to side with my old Whipple pulley (which had a LOT of belt dust on it ). I ordered up another 3.25” Griptec upper since I sold my last one to KingLT1, thinking I wouldn’t need it anymore…oops… So now I have 2.65, 2.85, 3.00, 3.25, and 3.50 Griptec uppers, the original 3.65 Whipple upper, and 7.00, 8.00, and now 9.25 lower pulleys all sitting on the shelf.

The new pulley combo is huge so my current belt is not going to fit. I took a couple of measurements then chatted with Laynlo15 about possible belt sizes. I took his advice and called OffRoadBelts.com. Super helpful and cheap! About $17/each for 10-rib belts. So I ordered 2 different sizes in hopes one will work for me. When those get here I’ll put it all back together and hopefully find the last bit of power I was hoping for out of this blower.

PS: love the box my TooHighPSI pulley arrived in!

[KingLT1]

I like the box and good info on the lower!

[Joshinator99]

So, with the new pulleys on boost is up slightly but still not right. I think my tensioner is either on the way out or just not beefy enough to hold the boost level I’m trying to achieve. So, out comes the plastic again, and I just ordered up TooHighPSI’s entire tensioner upgrade package. If this doesn’t do it, I quit.

[Joshinator99]

So the new tensioner setup arrived from TooHighPSI. The bracket is a thing of beauty! The difference between the standard LT4 tensioner and the new LT5 tensioner is pretty dramatic too. With the new pulleys in place I needed to order more belts again…I’m quickly becoming Off Road Belts best customer… (EDIT: I won’t be using these belts anymore as I describe below…)

With the new belts in hand, the tighter belt that I was hoping to run is just too small. The backup belt is just under 1” longer and still doesn’t fit either. But it did fit if I run a 3.00” upper (instead of the 3.25” I wanted to run). I marked the min & max tensioner locations with a sharpie marker and it looks like I’m about 75-80% tight in the tensioner which I think is good… you don’t want to max out the tensioner but want to give it plenty of tension on the belt.

I didn’t get a chance to test it yet, but this new pulley combo (9.25/3.00) is really going to spin the ported Whipple HARD. This is well beyond Whipple’s max recommendation of 18,000 RPM (will be just under 21,000). Since it’s maybe one track day or so, and I’m planning on upgrading this winter anyway, we might as well let it rip. Full send!

[Joshinator99]

So I went to the track today to test out the new belt drive. I spun on the first run but still trapped 147 and change so that bode well. Next run I still spun some and my 60’ was only 1.60, but ran 9.72@148.77! MPH was very promising. Next run I hooked a little better but then at half track my blower belt snapped! It took out the OEM thermostat housing and made a mess, ending my day. Although I had always run Dayco belts, I was using one of the D&D Powerdrive belts from Off Road Belts, so I’m definitely kicking myself. The problem here is I’m asking a blower to do way more than it was designed to do. This 2.9 is pushed to the max and this is the result. Oh well, had to give it a try.

I brought her home (thanks to the guys from Jays Auto Body at the drag strip with their beautiful ~’69 Camaro for helping me push my car onto my trailer!) and gave the entire car and engine bay a bath to get all the coolant off of it. Tomorrow I’ll start assessing all the damage.

[KingLT1]

Well dang it!! Looks like you picked up some anyway. How did the trans feel?

[Joshinator99]

Originally Posted by KingLT1

Well dang it!! Looks like you picked up some anyway. How did the trans feel?

Seemed like it was shifting great! I’ve got to take a closer look at my logs but things were running strong as heck but I need to move on from this blower. I’ve just outgrown it and the efficiency is too far outside of where it should be. I’ve known that for a while now so I’ll need to make a decision soon. I guess my options are: Maggie 2650, Whipple 3.0, or twin turbo.

[KingLT1]

Well, that is easy...3.0 but I don't think your 2.9 is done yet. I would put a good name brand belt on and try again. Your setup should go low 9's, just need to sort out the suspension and play with the timing more to get it to hook.

[Joshinator99]

Originally Posted by KingLT1

Well, that is easy...3.0 but I don't think your 2.9 is done yet. I would put a good name brand belt on and try again. Your setup should go low 9's, just need to sort out the suspension and play with the timing more to get it to hook.

I ordered a laser belt alignment tool as I just want to be 100% sure the new belt drive system lines up perfectly with the Whipple 2.9. Given that TooHighPSI never testing this drive system with a Whipple, I’d rather check that personally to make sure before I put a new belt on.

Plus, I ordered a billet thermostat housing from Speed Engineering so that I don’t end up in this situation again. The coolant made a mess and took me a while to clean the car top to bottom. Then I ordered a new water pump/alternator belt since my original one got destroyed by this mishap, and I ordered a new AC belt too just in case. And I ordered new coolant hoses too as a precaution, and still need to order a new hood liner. Then measure up for good quality Dayco or Gates belt. I’ve always used Dayco with good luck, this was my first time trying another brand and I got burned. The Dayco is American made, the one from Off Road Belts turned out to be a Chinese one, FWIW.

Appreciate your support as always King, and agree. The 149 trap speed made me feel good! But I know I’m wasting a ton of power turning a huge rotor pack that is way outside its efficiency range. The 2650 will likely take 25% less power to turn than my 2.9 being overspun. Definitely tempting lol…

[KingLT1]

If the 2.9 was that far past it's efficiency range your back half mph increase wouldn't be that strong(+34mph). Look at max effort LT4 blower cars and compare the difference. Those are being spun well past their efficiency range. They will trap 119 in the 1/8 and 146 in the 1/4. You just need to work on the front half and the car will get a lot quicker.

[Joshinator99]

Originally Posted by KingLT1

If the 2.9 was that far past it's efficiency range your back half mph increase wouldn't be that strong(+34mph). Look at max effort LT4 blower cars and compare the difference. Those are being spun well past their efficiency range. They will trap 119 in the 1/8 and 146 in the 1/4. You just need to work on the front half and the car will get a lot quicker.

Good points as always. I’m going to try to get everything put back together and try to sneak in another test and tune before the weather sets in. Agree totally that I need to get that 60’ down. I was already starting to see some benefits to the traction situation by ramping in the timing more smoothly just in the few runs I got, so I’m looking forward to dialing that in.

One thing I’ve never done is yank the front sway bar. Is that worth the time to do?

[Trochoidal]

Originally Posted by Joshinator99

Good points as always. I’m going to try to get everything put back together and try to sneak in another test and tune before the weather sets in. Agree totally that I need to get that 60’ down. I was already starting to see some benefits to the traction situation by ramping in the timing more smoothly just in the few runs I got, so I’m looking forward to dialing that in.

One thing I’ve never done is yank the front sway bar. Is that worth the time to do?

I’ve never yanked the front sway bar as I didn’t think it mattered. Looking back at Pray videos, his car always squatted a lot more than most. Did he pull that sway bar, IDK. Talking with Duramacr1 one night and also watching videos he shared, his car reminded me a Pray’s car.

There ya go, a paragraph of no direct knowledge. The next time I’m out I will try it for sure.

[Joshinator99]

Originally Posted by Trochoidal

I’ve never yanked the front sway bar as I didn’t think it mattered. Looking back at Pray videos, his car always squatted a lot more than most. Did he pull that sway bar, IDK. Talking with Duramacr1 one night and also watching videos he shared, his car reminded me a Pray’s car.

There ya go, a paragraph of no direct knowledge. The next time I’m out I will try it for sure.

Yeah I’m just wondering if I’m at the point with this much power, where simply slapping on the drag pack constitutes enough prep work to get my car to hook up at the track.