Techniques for spooling a large turbo on tight converter

[Razor]

Looking for information on spooling a large turbo on limited converter.. thoughts.

Nitrous, BOV open then shut, timing retard, fuel in exhuast, etc..

How big of a turbo.. what and how.. how long.

How do the big guns with Buicks leave on a pro tree with a larger turbo?

 

[johnplogii]

I don't know if this helps any but my staging procedure is to pre-stage, load the chassis to 0-1 psi boost on the footbrake, engage the transbrake, build the boost to desired level or close then let off the footbrake & roll into the second staging light all ready to go. This works great 19 times out of 20 but every once in a while I'll accidentally deep stage or the roll off the chassis load isn't quite enough. You just need to know right where to stop in the pre stage.

 

[Razor]

This is how i've been doing it as well.. sometimes it overshoots the second light.. you need to creep exactly ovet the first light.. so it clunks forward lighting the second bulb.

This is all and well.. until you have some azzz on the other lane playing staging games... or the starter takes hime time bringing the bulbs down.. you can go into meltdown.

I was thinking get the car into 1-2 PSI part throttle.. lock the T-brake..as soon as both bulbs are lit.. mash the gas pedal have the nitrous activate off TPS like from 2800-3700.. guess it should be in full boost by then..

Thoughts?

I've heard the Mustang guys using a blowoff valve .. big one.. they open up so the turbo can spin easily.. then shut it to bang the boost up.. Anyone ever try this?

 

[yullose]

A fogger nozzle in the up-pipe, with a #42 fuel jet and #46 nitrous jet. Should be good for 100hp at the wheels and instant spool.
I used it on a bone stock engine/trans combo running a TE62 and it was "instant spool".
From a dead idle the car 60ft'd 1.64 at Cecil and picked up 1.1 seconds.
From 12.25 to 11.15

 

[John Wilde]

I have heard of people using a two/three step, C02, N20, BOVs and regular tuning tricks!

 

[VadersV6]

Wouldnt some high capacity electronic air valves on a multi chamber manifold with some pressure switches do the trick? I have tons of them here at work....lots of SMC stuff for the automation lines we design/build. Want to try it someday. Use a valve to open the puck all the way just for half a second to get it spooling then close it halfway for another quarter to half a second, then close all the way until u reach the right boost level u want then it opens again. trying to spool fast from low rpm with the puck closed all the way seems like it would be similar to trying to launch in 3rd gear. It needs to be gradually brought up. But dont programmable boost controllers do all this anyway?

 

[Alky V6]

A fogger nozzle in the up-pipe, with a #42 fuel jet and #46 nitrous jet. Should be good for 100hp at the wheels and instant spool.
I used it on a bone stock engine/trans combo running a TE62 and it was "instant spool".
From a dead idle the car 60ft'd 1.64 at Cecil and picked up 1.1 seconds.
From 12.25 to 11.15

Nitrous is the way to go!

You don't have to fool around at the lights trying to get the boost to a certain high level, then hope you don't over shoot the pre-stage. If you set it up right, it can be easy on the drivetrain too.

This is what I'm doing. I bring the car up to the pre-stage. Foot brake it and bring the rpm up to 2200 rpm. Not too high, right? I then stage, engage the transbrake and bring it up to 2800 rpm as soon as possible and hold it. Some of those starters are quick with the lights you know. As soon as I see the flicker of the first amber, I floor it. I have a pretty tight T/C and without boost will only stall to 3200 at the most. My nitrous system is setup to activate at 4 psi boost and 3370 rpm. When all my timing is on, the split second I leave the line, the nitrous will activate, no sooner. This takes a lot of the shock load off the drivetrain when I release the transbrake, but just after I do, pull motor pull!!!

One thing that needs to be understood when using a transbrake is that from the transmission on back the drivetrain is relaxed. That means that some backlash is going to be taken up when the transbrake is released. That's one good reason to run your final drive backlash on the tight side. That small bit of momentum before the backlash is taken up is very hard on components. It's like a small jack hammer going at your transmission planetary gears, output shaft, front driveshaft yoke, u-joints, ring and pinion, differential gearset, axle splines and shaft, wheel studs. You get the idea. Having the nitrous activate just after the backlash is taken up is better for the wear of the whole drivetrain.

It takes .4 seconds to reach 16 psi, which is where I de-activate the nitrous and let the turbo alone take over. I still have half a ten pound bottle of nitrous left. It is the first fill on that bottle. :tongue:

Oh, by the way, that's a 200 HP shot (more like 150 with alcohol), with a single BB T76 w/.82 AR. T76 is at the limit for my app. Wish I had a 91. I know the N2O would have no problem spooling it. :wink: