trying to light turbo on tbrake

[87lsttop]

Need a little help When tuning a car to light the turbo off while on the transbrake and 2step I have read many threads in which to run as much timing as possible to get the turbo lit and then feather it out after leaving. I have logged many times and adjusted timing in the base table going from 18 degrees of timing all the way to 39 degrees of timing and it seems the turbo will only build 4 lbs of boost in 5 seconds. turbo is a tc78 Benita series with the 68 mm turbine in 96 a.r. I would think it spool like a light switch. I have also adjusted the PE to table to command . 84 lambda at the specific rpm while on the transbrake. Method for attempting to build boost while testing is to come off idle, hit t brake stab throttle, come up on converter and 2 step and hold it there for 5-6 seconds for testing purposing then release throttle and brake button. Doing this is in the dirt for testing so I don't break anything. Is this the appropriate method and way to accomplish lighting the turbo off on the brake and adjusting the tables in hp tuners. Thanks for the help and sorry for the long read. Here is a copy of the tune and a log

[87lsttop]

Well just ruled out the turbo being an issue. Made a pass and it built 17 psi

[Fast4.7]

Have you tried decreasing the timing to build exhaust heat and energy? Say reduce to 10? or even less?

[Fast4.7]

Also fatten the mixture some that fuel is still burning when it enters the manifolds.

[87lsttop]

I have not tried the timing that low. Every thread I have found for an auto car says to increase the timing significantly and lean the mixture out. So in my main spark table I was altering the table at the transbrake g/cyl and rpm and them also leaned out pe a bit in that rpm range. Not sure if that is the correct way to do it.

[Earwax]

Are you using a MSD 8733 2 step?
Does the engine miss/cut out when activated?

[Ben C]

I am surprised you found even one thread that says to lean out an run alot of timing.




Actually, maybe in a roll on without 2step it might work

[87lsttop]

Yes I am using the 8733. The engine definitely cuts out when activated.

[87lsttop]

https://ls1tech.com/forums/forced-in...uch-boost.html

From what I'm gathering it's different from auto to stick car. Mine is a th400 with brake and fyi 3600 stall

[68Camaro]

is this on gasoline, e85 or methanol?
tuning to light the turbo is different for each

[68Camaro]

if on gasoline -

tune timing and fueling to achieve highest flash rpm possible at the initial hit of the throttle against the transbrake - usually about .78-.80 lambda and 25 ish on timing
just as soon as the turbo starts building boost 1.5-2 pounds boost - take timing away and richen the mixture to about .74-.76 lambda (I can usually accomplish this tweaking the transient tables)

[87lsttop]

This is on e85

[68Camaro]

I've had E85 work with the above method and also had it work well with keeping timing in it (20-25 degrees) and keeping fueling around .78-.80 lambda - E85 is a little more combination sensitive

what is your converter?
what is your 2-step set at?

I have had converter issues cause problems with lighting the turbo off as well.

your method of spooling the turbo against the transbrake is how I dial it in also

[lt1z350]

On the old all wheel drive eagle tallon/ Mitsubishi Eclipse we retarded the hell out of it and added fuel and got instant boost. Same with old gmc typhoon. Rich and retarded weird you found to add timing somewhere. Been doing this before could even get into ecm programming using retard boxes two steps and fmu. Lol once you hit on it hold the hell on. Back in the day was a secret.

[87lsttop]

I'm gonna try and riches the mixture up this afternoon. My converter is kinda tight so it doesn't instantly hit stall. It stall to 3600 On the brake but will gradually build stall longer I'm on it. 2 step was set at 3700 yesterday during testing g

[lt1z350]

Retarding the timing also makes it burn more in the pipe and near the turbo causing it to spool. With the talon we did it on tight stock torque converters so a 3600 stall gives you so much more to play with. Shouldnt take a lot of rpm to do it when set up right.

[87lsttop]

Am i correct in thinking that the timing should be adjusted in the main spark table? Also fueling adjusted in the pe table at the specific rpm?

[lt1z350]

I haven't done it with new stuff so hopefully someone that has will add on how to do it. Main spark might be hard as could hurt driveability. Already using a two step add a timing retard module to it if one your using can do that. I guess could do a log get it up on the brake and see if where it is falling in at is a weird area for timing table and maybe won't see it under normal driving. If no one else will help get a log with it on the brake and post that and a tune and I will see what looks best for it and try to help out. I was familiar with what it took to spool it just not totally sure how in the tune and not hurt any kind of driving but sure can take a look.

[87lsttop]

Ok so here is log and tune. The commanded is .82 dropping down to .76. I have adjusted spark in the region from 10 degrees all the way to the current timing in tune. 2 step is set at 3800 rpm. Only builds about 4 psi the longer im on it.

[87lsttop]

Is 5 seconds long enough to be on the brake to build boost?