Some of you have been following my progress with my buddys T/A. He had an Ed Wright chip that was drivable for the most part...still not right tho.

My question is do the 730 and 747 operate on a basic enuf level so I could take the VE tables from the 730 Ed Wright chip and use them in the 747? Feasable ????

I don't want anyone to think that I'm copying the Ed chip for something else...I'm not ripping it off. It's for the same guy, same car...just a different injection system.

TIA

 

Uhhhhh, your buddy had a TPI and went to TBI? But to answer your question, no, I don't believe you can. The 730 doesn't do a fuel calculation like the 747. I think the 747 does some funky thing with two tables with one being added to the other. I wish I could explain it better but it's just too different.

 

After giving it more thought I did remember the 2 VE tables from the 747. Also I would have to figure the difference in BPW / injector flow rate...blah blah blah.

Yes we took the TPI off. TBI works better with his combo. It would've cost another 4.3 billion dollars for some stupid runners/plenum/base to make everything match.

 

sure, why not, ever look at an lt1 ve table and compare it to a tbi table? theirs is all added up in one table i think.. but they are very close after you tabulate everything , i just did this last night (you can tell which one is the more high performance engine though) provided teh injector constants are set correctly on both chips it should work n/p how about you take a look at that table youll see what i mean

in fact starting off with an LT1 table might not be a bad idea

 

aw come on v8astro captain,you been eyeballin the tpi for yourself. What does you van do in the 1/4?

 

Hell no! TPI in my van would be a nightmare to work on. My Stro runs a 14.6 @ 91.7 mph.

 

Hell no. VE stands for "Volumetric Efficiency" for a very good reason. The "Volumetric Efficiency" of a TPI and TBI system are completely different. Even if the "numbers" were directly compatible, it would still be a complete mismatch - the TQ charateristics are all wrong.

You'd get far better results with a stock VE table from a 7747 and modify from there.

 

i hate to disagree with you glenn, but a stock 7747 ve table for a tbi setup will be just as far off if not more far off than the ve tables for a tpi setup, especially a calibration on the tpi setup that actually ran the long block underneath it. Considering of course that anything from the injectors down on that tbi motor is about a million miles from stock
compare two sometime

 

Trust me, the VE tables from SD TPI is not the place to start if you plan on tuning a TBI setup. The VE Tables for a Miniram, Superram and stock TPI are all different. Will the VE Table for a Miniram work well on a stock TPI? How about a stock TPI on a Miniram? Of course the answer is no.

So why would the VE table from a TPI work on TBI, which is a short runner system? The answer is, it won't...because the VE charateristics of the TPI system is quite different from the short runner TBI system.

And this is not even considering the fact that the two tables are not directly compatible with each other.

In all honesty, it is far easier to start with a "blank piece of paper" (i.e. stock bin) than try and "re-hash" a custom bin designed for something else.

 

lets see one is wet flow the other is dry,two different beast.

 

its not that different kvu, both are speed density systems.. the main differences will be during transitional areas like pump shot etc.. the main ve tables dont really affect that stuff so much

yes tpi is a long runner system, and i think everyone knows that runner length and size is going to affect your volumetric efficiency curves. I think the mistake you are making is thinking they are the END ALL and BE all for said curves. Camshafts, cylinder heads, compression, exhaust, vehicle weight.. gearing... all culminate to have a much larger effect on volumetric efficiency than just intake design.

In V8astros situation the engine is far enough from stock that no stock VE curve will suit his motor even near right. If we make the assumption that the custom prom he has is close enough to run well as he states with one intake manifold.. Then change the intake manifold and that is what will judge how far off the calibration will be from where it was from rather than being a camshaft, cylinder heads, intake manifold, exhaust, gears and what have you away if he started off with a stock image.

I couldnt tell you if the numbers correlate directly to the ve tables in a 7747, common sense would say yes since VE is VE.. and I have studied lt1 tables and found them to be very very similar except torque peaks are much higher than your average tbi dog motor chip has.

Astro, why not just try it? wont hurt anything.. and like you said, it barely runs with the tbi chip. Got nothing to lose... ive tried worse and guess what its been damn near three years and my 305 still runs... strong i might add. Chicken Littles Be damned.

 

btw the funky thing with the two tables is that they are added and at 3200 rpm the last cell you were in in the first table is added to the corresponding rpm cell in the ve2 table. I think anyone can figure out how to essentially copy ve curves from a chip that had just one ve table.


one thing of concern that ive been looking at is the 7747 doesnt really have any math to calculate the gms/sec airflow like the 730 does. (i glanced at the 730 setup... it does all sorts of crazy stuff) It does have a map scalar but i still cant figure if its added in or even how to do the math for gms a second through it. Al lthe times ive done it i end up with 130/140 gms a second max at 6000 rpm at 100 kpa and that would be assuming 100% ve since its only calculating max possible. This is using the stock constant which does vary by ci application. Its the only thing i can think to make up for the injector constant calculation that is only a multiplier for the various other tables it would cut fuel out across the board from what i gather this other one is multiplied by map and rpm so its like a snowball effect, basically makes a scale larger or smaller (if you lower the number) as the name implies

if you are looking at 7747 code have a look at it its at ld2f5 and just follow the trail youll see what im talking about if you can figure it out that would rule

 

Thanks for the input. Good discussion...

BUT we started from scratch and got it relatively close.

 

good deal let us know how it runs at the track when you get it sorted out should be interesting