Z32_5.3

I have EBC, I set everything to 0% then raised only the duty cycle until hit close to my boost. Then played with gain very little bits. At first I had vacuum lines plumbed to only one side of wastegate and it was a struggle for sure. Once I hooked up vacuum lines (correctly) to both side of the wastegate, it was so much better. Not sure if you have 2 nipples on your WG or not.

Fallguy

i have a 3 port Mac plumbed to the top and bottom ports. But I had the valve working before my target boost. It’s probably leaving some tq on the table

Deude_Mann

If it broke I could see the diff failing where it was locked up like a spooled diff. If something fell out of the diff I suppose it could jam the R&P gearing. At any rate I do not think it would fail easily since the gearing in the diff is very beefy, and the load is distributed across a lot of gear faces. The R&P is reportedly much weaker than the Truetrac itself.

There was an older design, say 5-6 years ago or more, where the bolts that hold the diff case assy together were shearing and failing. But Allison beefed up the housing and added more bolts and thus all the new ones do not have that weakness. I made sure I had the newer version when I ordered it.

SLOW SEDAN

iTrader: (13)

Nice gain!

Assuming you have the proper tire/suspension to hook more lower end torque it can be great, it can also make the car a ton slower if you can't put it to the ground. I agree generally you want decent timing in them until the turbo(s) are lit but half the time on the street we end up pulling timing via some sort of traction control to get them to hook so its a catch22.

slowride

iTrader: (3)

I’m quite surprised at the gains at that low of boost/power. It’s a great test though thanks for showing us. You went to the 1.02 right? Can you have the dyno shop overlay the old vs new?

ddnspider

iTrader: (26)

back pressure ftw.

Fallguy

yeah it’s wasn’t that great. But I’m thinking that’s all the fuel would take. It didn’t want timing so we added boost to make 600

Don’t know what the limit of pump gas is. But you seem to see 550-650 max on pump with no meth

slowride

iTrader: (3)

Understood just nice to see some back to back comparison. You need to find some e85 😁

SLOW SEDAN

iTrader: (13)

Did you want more than 600hp? You can keep going on pump but you have to keep timing in check, when I ran ~20PSI on 93 I couldn't get more than 11-12* in it without it complaining.

Fallguy

im not too sure if I want to push it much past that on pump. It gains 20hp per lb of boost and the motor seems healthy (175psi on all 8) yet the power seems low for that amount of boost. We are definitely adding timing till the power it picks up is only 10hp per deg. And the plugs are showing that as well.

im going to test my map sensor to see if it’s reading the right amount of boost. It’s a ZR1 3 bar map. The haltech had the calibration for it.

SLOW SEDAN

iTrader: (13)

Gotcha, I'm sure its fun to drive either way. At some point those low profile rear tires will come into play as a limiting factor if they haven't already.

Fallguy

yeah it rips pretty good. Just want to make sure nothing is holding it back. But so far I can’t seem to find anything. I’ll hook the map sensor up to my compressor to see if it is reading what the regulator says.

im running 8psi springs but it goes to 11psi. But I don’t think that’s anything too odd.

slowride

iTrader: (3)

How much did the housing swap change the boost onset?

tblentrprz

Good results. Any idea what backpressure is now?