LB7 How-To?

[jrcmlc]

I've gotten pretty familiar with the procedure for LBZ-LMM and learned quite a bit, but I was hoping to find a similar how-to for the older trucks that have LB7's.

Is there such a how-to, or something specific to reference as an addendum to the already-great how-to's for the LBZ-LMM?

Thanks,

JC

[mecanicman]

No, there is not. Procedure is pretty much the same though. Torque management tables are a little different. Turbo is not variable vane, so no vane position tables, and it is hardcoded at 22 PSI boost(i think that is the value). Dont get carried away with the fuel unless you have a boost fooler, your egts will skyrocket. A pyro is an especially good idea on these.

[jrcmlc]

I downloaded a stock file to look at.

Under engine, tq management, general it has a max tq as well as a tf case max and front halfshaft and front propshaft max, then a rear axle max and a rear prop max. Is there a figure I can apply to all that would be safe, or ?

I'm going to do a truck for a friend who just wants a little more power and mpg, nothing big at all...

I'll be using your calculator for the timing tables I assume...

JC

[jrcmlc]

There is also no "driver demand" or pedal position vs torque to increase the TPS values...are they located someplace else or ? Is there another table to modify in place of this and if so, are there some recommended % increases?

What about on the injector pulsewidth, there are "main pw" "main pw no pilot" and "pilot pw"...should I change all of them the same 20%? If so, where is the starting point on the table, the table is different than the LMM?

JC

[ajamesbond007]

There is also no "driver demand" or pedal position vs torque to increase the TPS values...are they located someplace else or ? Is there another table to modify in place of this and if so, are there some recommended % increases?

^^^ No torque tables for pedal position. Its all TPS and Base Qty Fuel tables. Basically pedal position corresponds to a certain mm3 of fuel.

What about on the injector pulsewidth, there are "main pw" "main pw no pilot" and "pilot pw"...should I change all of them the same 20%? If so, where is the starting point on the table, the table is different than the LMM?

JC

More than likely, you will be using the main injection with the pilot active, but you can change both and be fine.

[jrcmlc]

I'm having a brain fart on this, can you point me to the table directly so I can be sure I'm on the right track? I think the only ones I've done were newer and didn't need to be adjusted this way.

Thanks

JC

Originally Posted by jrcmlc

There is also no "driver demand" or pedal position vs torque to increase the TPS values...are they located someplace else or ? Is there another table to modify in place of this and if so, are there some recommended % increases?

^^^ No torque tables for pedal position. Its all TPS and Base Qty Fuel tables. Basically pedal position corresponds to a certain mm3 of fuel.

[ajamesbond007]

Look under Diesel > Fuel >Based Fuel (Upper left hand corner) should be a table for RPM vs TPS with mm3 in the actual cells

[ajamesbond007]

Let me know if you still can't find it. <-- post your stock tune and I will screen shot the table

[jrcmlc]

Thanks, yes, Engine, fuel, diesel, Base fuel quantity, base qty vs tps.

Could I do 1600 rpm x 40% tps and add a certain % to anything above that range? Suggestions on how much %?

What about boost...I understand I can't add boost to make up for the fuel change because the boost is fixed...?

JC

[ajamesbond007]

I am not an expert on the LB7's, but the general rule of thumb is you want to add the same % of boost to the area where you added fuel. Of course, if you are already at the 22 limit, mechanical upgrades are needed at this point. Pryo is a definite. You should be fine with about a 10% increase, but I would not go anything above that. <-- and if you do go 10%, don't stay in it very long (more than 5 seconds) until you can measure your EGT's to see where you are.
Play around with it and if you want me to look over it, let me know. Email is [email protected]

[ajamesbond007]

This week I am a little busy, so I won't be able to get to it until Thursday

[jrcmlc]

I _KNOW_ this guy is never going to put a pyro in it, but I was thinking 10% would pretty safe.

The "max boost" table in the stock form is already set to 255kpa all the way across 1400-4800, only below that is there room to move the boost table up...

JC

[jrcmlc]

In engine, tq management, general, do the tq limits listed have any real bearing on anything...does it use these? If so, is there a high limit I should adhere to if I raise them a bit?

JC

[ajamesbond007]

I _KNOW_ this guy is never going to put a pyro in it, but I was thinking 10% would pretty safe.

The "max boost" table in the stock form is already set to 255kpa all the way across 1400-4800, only below that is there room to move the boost table up...

JC

Then that's all you can do. Don't do any more, not worth your time as a tuner. And move that boost table up. You could get an additional gain (not sure how much but probably worth while) from a timing calculator Mecanicman has posted, even with stock pulse width tables. It's in this forum somewhere.

[ajamesbond007]

I can't answer any of the torque questions yet. Don't want to feed you the wrong info. Hopefully someone more experienced will chime in on that. Personally, a 10% increase shouldn't do much when it comes to defueling problems.

[jrcmlc]

Good. I intended to use mecanicman's calculator and use the 50% calculator. I downloaded some other folks different tunes for this truck and they have modified tables that I don't understand, such as base fuel qty vs tps vs rpm, and max fuel qty vs airmass vs rpm...

Simply put, if I edit the boost tables, and the base qty vs tps, edit the pulsewidth tables and do the timing calculator, is there any reason that won't make a reaonsable, mild tune?

JC

[ajamesbond007]

Simply put, if I edit the boost tables, and the base qty vs tps, edit the pulsewidth tables and do the timing calculator, is there any reason that won't make a reaonsable, mild tune?

JC

Do either the pulse width table or base fuel qty vs tps table for the 10% increase. Don't do a 10% increase on both if no pryo. You can split it 5% on both, but like I said no 10% increase on both. Not worth risking anything. I am sure everything would be fine, but lets keep it simple and the customer happy. I would rather have him slightly underpowered and have everything hold together than slightly overpowered and 3 months later he needs to replace something. Plus if you are a vendor, could be a good way to sell some stuff by holding a more powerful tune until he has some mechanical upgrades. 10% increase is around 40-60 horsepower. Be a good mild tune.

[jrcmlc]

LOL. Customer=Cheapass friend. :-)

10% in the PW table and the pilot pw table acceptable and leave the fuel/tps alone?

JC

[ajamesbond007]

^^^ hahahaha, I know the type lol.
Sounds good. Do not change the pilot pulse width table. Just change the mains (one with pilot injection ON and one with pilot injection OFF).
Going this route, you will find that the extra power is only noticeable until you get past the point at which you modified the pulse widths. So if you keep everything stock from 50% TPS and below, your truck will feel stock from 50% TPS and below. It won't be until you get past 50% that you start to notice anything. This is kinda the draw back of going just with pulse width modification. Usually why I do a combination of both, but to each his own. You could just do the Base Fuel qty across the board (all TPS values increased by 10%) and you will notice that the "pick-up" in the throttle has increased, or has become more touchy. ^^^^ Information overload. Do what you are comfortable with

[jrcmlc]

I bet he would like the idea of 5% in the low tps levels and 10% in the higher tps areas...that way it feels peppy all of the time and progressively more peppy the more pedal you give it. Probably do that instead of just PW, he'll be happier with that.

Thanks for the help, I think I understand enough to do this very basically, which is about what he needs.

Thanks again,
JC