With all the available downloaders and such, we awta be able to set our rigs up for both towing and racing. Just turn tst or whatever you run off, and change your download program for towing. Right? What do you think the best settup would be? I know I am planning on rv275 injectors, ordered the smarty, but not sure yet on turbo setup or what to stack.

 

Here's something to consider:

Truck bombed with TST/smarty/Mach4s/appropriate turbo: ~500hp.
Truck with all that stuff, but TST turned off: ~400hp
Same truck, TST off and Smarty at half power: Basically stock.

The Half-power SW of the Smarty can really tame a radical truck. It's a great valet mode and will make a truck with 150hp sticks drive almost like stock (maybe a little less power).

The difference between a box off and a box on is substantial, but adding the Smarty and it's half-power (emissions) mode to the mix can radically change things.

With this SW on my truck, I could barely generate any smoke with big injectors in high altitude. EGTs were a complete non-issue (worked HARD to get it up to 1100º on a hot day in thin air).

Justin

 

thats what i'm talking about! Thanks Hohn. What is your appropiate turbo if you dont mind my asking? I thought this would work. And do you tow any?

 

I tow rarely-- basically never. My truck could easily be replaced by a little small Toyota or something. I bought it because I wanted a truck AND a hotroddable Cummins--period.

As for turbos, that's a tough one. There are tons of turbos that will work "OK", but the one that's BEST for you is as unique as your circumstances and driving style, and such.

Compounding the difficulty is your automatic tranny. With a stick shift, you can control the shifting, but the automatic can be difficult to make cooperate with a larger turbo. You could be acclerating along nicely, only to have your tranny shift and bark the turbo, or take you out of its range and all your power disappears and you have smoke and no power.

Because of this, an auto tranny truck needs to have a tighter turbine section, imo, to bring the turbo in earlier and will therefore have higher EGTs when you are playing around a bit.

What *I* would do if I had an auto tranny truck is I'd match the torque converter and turbocharger response levels, then match the fueling to the airflow, ideally such that with a box off you'd be able to tow with little to no EGT issues, then turn up the box when empty to play.

As useful as the Smarty's half-power software is, I wouldn't recommend anyone use it as a "towing mode" unless you have huge injectors (200hp range) and simply have to. It's easier to just back off the pedal and drive a little easier.

It's also a really good idea to manually shift your auto trans when towing in hilly terrrain. You're simply smarter than the best auto trans.

So, start with TC and turbo matching. You simply must have a turbo that will be within it's operating range before the stall speed of the torue converter is achieved. Unfortunately, stall speed changes with engine output, and engine output at low RPM changes with turbo choice and engine load-- so you can see how you can spend all day going in circles.

Even though it isn't an accurate representation of true stall speed, you can use the old "brake torque" method to roughly gauge the stall point of your converter. Stand on the brakes and loud pedal at the same time and see how far your RPM will climb. If it goes up to about 2K rpm, you know that you have to have a turbo that will spoolup by 2K rpm (even 500hp range turbos usually do this). But if you can only get the RPM up to 1700 when braketorquing, then you need a small turbo.

Now the brake-torque move (both brake and acclerator pedals pushed) generates a LOT of heat in the transmission, so please don't do it very long and let your trans cool for a few minutes before doing it again. The looser the torque converter, the more heat will be generated.

In this regard, the factory torque converter is about as bad as it gets. It's VERY loose. This is partly why the factory turbo on the 01 and 02 automatic trucks is so tiny-- the tranny won't apply much load to the engine (it's sooooo loose), so the turbo won't spool properly unless you install something tiny. That's what the factory did.

So, first things first-- get your tranny done/upgraded before you add any power. Then, you'll be able to get a feel for when it "bites" and applies the power to the ground. Each tranny builder sets theirs up a bit differently. Based on the tightness of your trans, pick a turbo. If it's pretty tight, you'll want something that's only slightly bigger than what you have right now-- like go to an HX35/40 hvbrid, an HTT HTBG, a BD Super B, or an ATS Aurora 2000. With a really tight converter, you'll want to stay within the 54mm-62mm inducer range. So the smallest upgrade turbo you'd want to consider would be the HX35 off a manual trans truck, and the biggest you'd want to consider would some something like HTT 62/65/12 or 62/65/13ss from HTT or from I.I. a phatshaft 62, or from Turbonetics a Stg 1 T58 or from Garrett a Stg 2 GT37.

If your converter is a little looser, then you can go the next range up in turbos. This means the 71mm turbines are now an option: the HTT 62/71/12, 13ss, or 14 and the I.I. Super Phat Shaft 62.

If you have a really loose converter, you'd theoretically go bigger, right? WRONG. We get back into that situation where there isn't enough load applied to the engine to get a very large turbo to spoolup.

Bombing an auto trans truck with a single turbo is a VERY delicate balance because spoolup with an auto trans is the SINGLE MOST IMPORTANT part of determining whether your souped-up truck will still be useful to do all the things you bought it to do, or whether you just have smoke-belching toy.(just my opinion, again).

Add the fuel last, because then you'll know how much fuel you can add and still be useful. You can improve the bottom end performance of a turbo a little bit with more fuel, but don't buy the myth that something "won't spool because you don't have enough fuel." More fuel might increase the RATE at which a turbo spools, but it will NOT change the POINT at which the turbo spools. You need to be concerned with threshold-- the point where the turbo starts generating positive pressure (boost), and this won't change with the biggest injectors in the world. How FAST it spools will change with bigger injectors and bigger turbine sections, and this is where the "fun" factor can come in, because it gives a bit "hit" when it goes.

Don't trade too much work for play, you'll end up with a truck that won't do either all that well.

Sorry so long.

Justin

 

That is ok. I loved the info. All makes sense to me. What about going to a set of turbo's? I'm sure we could figure out a set that would work. But, I need to mention, that I am not planning on making my truck to much of a hotrod.....well.....i keep thinking about it. But I thought this might help others to. Thank you soo much for the info. I am thinking very hard about calling goerend and get tc and vb from them. I am thinking that with rv275's, smarty, and vb and tc I will be happy. But for how long, he he. I definately don't like to be beet by the other brands going down the road, loaded or empty if you know what i meen. I would be able to stack something for just a little more money. I am planning on spending some money on it now and want to make sure i go the right route that will suite my needs and work for me in the future if my foot keeps growing. He he. I guess you are right though and i think what i will do is wait till my smarty, and gauges show this week. I still need to find a good set of rv275's. I better slow down and not buy everything at once, I just thoght that maybe somebody already did this setup and would know what turbo would work the best. My auto, might already have some upgrades, I bought the truck off dealer used. The torque converter is blue but no drain plug. I am still thinking of calling goerend now because i have the money now. If not i would wait till my tranny goes, then probably won't have the money. Am i babling? anyway thank you
Ron

 

Hohn if that is the case with putting Smarty on half power which I know it is, could I not run injectors that are in the 200hp range so that I can play around and then when I go to tow just put Smarty on half power and turn everything off and be right where I'm at now when all my mods are off except the 100hp injectors? In theory this should work right??

 

Theory-- yes. I wouldn't run 200hp injectors with an HO pump, but they'd be nice if you had an SO pump.

Real world, maybe, maybe not. I'd personally stop in the 175 range for injectors if you want towability, assuming they were quality injectors with good spray pattern and such.

If you're willing to reflash the ECM each time you hitch up, I suppose it might work, but you're not going to get as clean atomization from a set of 200hp injectors as you would from the 100s. It might not be MUCH worse with the 200s, if they are good injectors, but it will STILL be worse. Bad enough to matter? Maybe not-- I have no idea.

I'd play with towing with a Smarty on half power before I went to big injectors, just to make sure it would work-- rather than buying the big sticks then hoping the Smarty tames them.

Why woudn't it work? Well, I'm not sure exactly how the Smarty limits power. Does it just limit how FAST it will let the torque be applied, or does it actually limit the fuel output? If it only limited the rate, then it's possible you could see really high EGT towing when you didn't have it empty, because as the load increased, the SW would allow more fuel.

I don't think this is the case, however, as my experience with the "emissions" software suggests that it limits both power output and total fueling, even under load. This would make it a green light for the "towing at stock HP levels" function I've hinted at.

Id'd HIGHLY recommend that you buy or try a Smarty in it's half-power mode and tow with it to see if in fact this does what you are hoping-- BEFORE you buy more parts in an attempt to make a truck that will both race and tow.

Of course, with the right turbo(s), there's no need to limit fueling when towing.

JMO

 

I own a Smarty and have played with the half fuel and it really makes it doggy, I hope with the turbo I have working properly I should be able to get away with injectors that are Mach 4's or hopefully even 6"s. Thoughts?

 

I think you'd have no problems with 4s. I ran my 4s with the stock charger with the half-power SW and she felt pretty doggy-- a little worse than stock.

JH

 

Lots of good info in this thread, it's all about choices. Just as HOHN stated "Don't trade too much work for play, you'll end up with a truck that won't do either all that well".

I've messed with the Smarty on half-power before with my big injectors, lets just say larger than 200 hp Will all the boxes off, just running the injectors and a HRVP44 it still slightly hazed going down the highway and had about the same EGTs??? I don't know how the Smarty turns the fuel back but that was my experience. The power level was cut back, took more pedal effort to get the response, but EGTs were still there. Maybe this is due to the larger injectors?

 

Excellent advise above....and I would do one thing at a time.... with at least two weeks between additions... to get firm understanding of how it performs, before making more changes.

The other big variable is how much weight you tow. 5000 lbs - not a factor. 10,000 lbs needs to be factors into set up. 20,000 lbs and towing become the defining element in what you add to your truck (and limits your play time additions).
If not towing heavy....
Wanting to do it right the first time around, AND not liking to get beat.... tells me you should skip the 275 hp injectors. A set of F-1, Mach 4's will make you very happy with the Smarty and a med sized turbo..... and adding a TST PM3 will give you the 500+ hp to play and 400+ hp for towing!

But do your CTD a favor and do the tranny first! Your truck will thank you for it.
And for the perfect set up for both towing and playing hard.... consider compound twins (now or in the future).

RJ

 

Thank you all for the advice

 

I suspect this is related to huge injectors and HRVP. Huge injectors can't spray as efficiently as smaller ones, so the same amount of fuel will run warmer on the EGTs, all else being equal. Oddly enough, I noticed slightly lower cruising EGT with my F1 injectors over my old honed injectors, which where about half the hp increase-- that points to a good level of efficiency, imo. The HRVP will deliver more fuel at all times, and the SW#0 will cut it back to half of the HRVP, but that's much more fuel than a stock HO pump with the same SW.

Justin

 

Justin, I noticed the same thing way back when I was running a single and went from DDII's to Mach 4's. I wonder if it is because Don sets the pop off pressure higher than stock? Can you just adjust any old injector for a higher pop off pressure pressure and get a more efficient burn?

Jesse

 

I don't know for sure what pop-off pressure does to efficiency. It would stand to reason the higher is better, but I suspect that rate-of-discharge is the reason Dons set the pop pressure where he does, not for any atomization benefit per se. If he could get the ROD he wanted by lowering Pop pressure, I wonder if he'd actually lower in instead.

Justin