Time to go stage II with A/C!

[norbs]

Don't forget that there is boost pressure reference on the back side of the diaphram if you hooked it up that way. Makes it open sooner than just back pressure alone acting against the valve. So two factors to consider.
Allan G.

You are correct.

 

[kidglok]

Take it out on the street and see if 5lbs is all she will make with your foot to the floor

 

[norbs]

Take it out on the street and see if 5lbs is all she will make with your foot to the floor

I'm testing this on the transbrake I think its the safest way right now..

 

[kidglok]

I'm testing this on the transbrake I think its the safest way right now..

4100rpm on the transbrake got you 9psi, at 3500 you were at 5. I dont think there is anything wrong with your setup at this point. Granted, the 27+ degrees of timing isnt helping spool the turbo, but, we are limited by the cubic inches that we have and can only produce so much exhaust energy at a given RPM, regardless of the wastegate.

 

[SCOOBY DOO]

Take it out on the street and see if 5lbs is all she will make with your foot to the floor

Drive it?

 

[kidglok]

Drive it?

Like you STOLE it!

 

[ttypewhite]

Drive it?

Brad, next time you go to see Norbs, pick up the wrench off of the work bench and introduce it to the side of his melon, maybe, just maybe that might knock some sense into him.

 

[BlownV6]

Put 35 degrees of timing in it until say 10# of boost and start ramping it out. That will tell you what you need to know.
When you coming up on the trans brake how are you doing it, and how long does it take to get to 4100rpm?? Mike

 

[norbs]

Brad, next time you go to see Norbs, pick up the wrench off of the work bench and introduce it to the side of his melon, maybe, just maybe that might knock some sense into him.

Relax...the tuning has just started..

 

[norbs]

Put 35 degrees of timing in it until say 10# of boost and start ramping it out. That will tell you what you need to know.
When you coming up on the trans brake how are you doing it, and how long does it take to get to 4100rpm?? Mike

I'm pressing the transbrake button and puttin the pedal to the floor..How long it takes to 4100 rpm is.......4.3 seconds, and I would say the gate starts to open around 8 psi, slowing the spoolup. I could add some more timing but I really want to retard it to to 3 BTDC total timing and put a heap of fuel in it on the 2 step and see the results. I need to test various ways, might have to wire in the Power adder features.

 

[kidglok]

I'm pressing the transbrake button and puttin the pedal to the floor..How long it takes to 4100 rpm is.......4.3 seconds. I could add some more timing but I really want to retard it to to 3 BTDC total timing and put a heap of fuel in it on the 2 step, I need to test various ways.

How much boost do you really expect

 

[norbs]

How much boost do you really expect

I say I should be able to launch at 13 psi minimum, but the target is 35 psi after launch using gate pressure no Co2. Not sure if this is possible with my setup. The 4 port solenoid is very tricky you can forget about closed loop boost control......I will not even try that.

Here is a video of the car with 0 degrees timing..listen to the turbo spin...

RPM never exceeded 1800-2000 moving the TPS

 

[kidglok]

I say I should be able to launch at 13 psi minimum, but the target is 35 psi after launch using gate pressure no Co2. Not sure if this is possible with my setup. The 4 port solenoid is very tricky you can forget about closed loop boost control......it will not work.

You shouldn't have a problem with that the way it is right now.

 

[BlownV6]

I'm pressing the transbrake button and puttin the pedal to the floor..How long it takes to 4100 rpm is.......4.3 seconds, and I would say the gate starts to open around 8 psi, slowing the spoolup. I could add some more timing but I really want to retard it to to 3 BTDC total timing and put a heap of fuel in it on the 2 step and see the results. I need to test various ways, might have to wire in the Power adder features.

I cant see 3 deg before TDC EVER working!! Yes clutch cars do this because it makes the engine very lazy and they can go WO throttle and move a lot of air to spin the turbo. With an automatic that aint going to be possible without nitrious. And you would still need more timing.
On Rocks twin turbo car with no staging equipment. I hold the brakes hard enough to get the engine up to say 4000rpm (takes a few seconds to do that) Then ease off the footbrake to get into the beams. Apply transbrake and from this point it will take approx 2-3 seconds to make it up on the 2-step at 5600rpm and I believe about 15# of boost. This is just for some kind of reference as to how long it takes to get an average combo spooled up.

Im betting that more timing makes everything much quicker and happier. Im out!! Mike

 

[Alky V6]

The way you have the boost control setup, you're relying a lot on the spring pressure right now to hold the valve closed against backpressure and boost against the release side of the diaphragm. I would start adding some dutycycle to that solenoid at this point, to get the boost any higher.

 

[Alky V6]

I cant see 3 deg before TDC EVER working!! Yes clutch cars do this because it makes the engine very lazy and they can go WO throttle and move a lot of air to spin the turbo. With an automatic that aint going to be possible without nitrious. And you would still need more timing.
On Rocks twin turbo car with no staging equipment. I hold the brakes hard enough to get the engine up to say 4000rpm (takes a few seconds to do that) Then ease off the footbrake to get into the beams. Apply transbrake and from this point it will take approx 2-3 seconds to make it up on the 2-step at 5600rpm and I believe about 15# of boost. This is just for some kind of reference as to how long it takes to get an average combo spooled up.

Im betting that more timing makes everything much quicker and happier. Im out!! Mike

I agree with Mike. Your best compromise of rpm rise and boost rise on the transbrake is going to happen with more timing against the transbrake. You're not using nitrous, so I'm not sure what the best timing number is going to end up being for your combination, but as an example with my car and the nitrous, when I first inject the nitrous at 2400 rpm, the timing is retarded to 10 btdc. As soon as the rpm begins rising, which is pretty quick, the timing ramps to 15 btdc by ???? rpm and stays there until I reach launch rpm and boost level where the nitrous is turned off. At that point, the timing returns to 31 btdc and the engine is able to maintain the launch rpm and controlled boost level. This strategy has given me the best compromise of rpm rise and boost rise.
Bottom line is, this strategy nets me the quickest time to launch rpm and boost level. The least amount of time having to stall the torque converter and build unwanted heat.
You have to keep in mind that rpm is what moves the car. Not boost. But boost does help you net a higher rpm level against the torque converter, as long as the timing is not retarded too much.

 

[Alky V6]

I should also add that stalling the TC for 5 seconds and longer is building a lot of internal heat in the torque converter. Make sure you are letting it cool down between tests. Generally expect a 50 degree F rise in temp per one second of stalling. Check your fluid for signs of degrading.

 

[turbobitt]

I couldn't find any gain retarding the timing when building boost. Always responded beter with timing. Now after the two step kicks in is a different story. Retarding timing on the two step may give it some more available boost. I really didn't play with that much on my car since It takes me so long to spool anyways I didn't want to spend any more time than I have to on the two step. Norbs shouldn't consider timing retard in the spool-up curve before two step IMO.
Allan G.

 

[HighPSI]

I say I should be able to launch at 13 psi minimum, but the target is 35 psi after launch using gate pressure no Co2. Not sure if this is possible with my setup.

I'll be interested in how well it works at 35 psi. I've never ran that small of an A/R on the GT4276. Nearly everyone runs a 1.28 housing or larger.
13psi launch is pretty optimistic. Should be good for some 1.2X short times if it hooks

 

[278cikiller]

This car has't seen the track in 5 to 7 years and i don't think it's going to see it for another year the way this going, our the car does't make the HP numbers Norbs what's.