Engine/Transmission (1998.5 - 2002) edge comp or edge comp hot

[PC12Driver]

It really only makes a difference on how the truck responds under acceleration. Once cruising, the fueling is equal between the levels. So it really comes down to how you want the truck to "feel", and how much smoke you want to make. And the frequency of cleaning the rear quarter panel.

Stacking a timing box such as a Comp on top of a tuner that does timing as well is a bad idea. Either one is advanced about as much as the engine can take, and if you put them together the timing adds up. If you feel the need to throw a Smarty in the mix, you'd need to run one of the non-timing programs. But that would negate one of the great selling points of the Smarty. Mix the Smarty with a non-timing box such as a TST Powermax though and you'd be good to go.

 

[BlitzkriegSSII]

How many miles do you have on your truck? I have an 02 with a little over 181,000 on it and the mpg is starting to dropping off some what, it has had a hard life at 566 HP for over 6 years. I think the VP44 may be starting to ware out some, I'm still on the OE injection pump. I put my Comp box with the HOT unlock on back in 06 and love it! It really does wake these trucks up The biggest thing I think is make sure you have enough fuel going to the Injection pump to keep it alive. Try some 150hp sticks in there and see what kind of smoke you can roll :-laf

 

[Joseph Donnelly]

Get gauges, especially a pyrometer, and you will also need a bigger turbo if you use a higher setting on the Edge box.

 

[Midnite]

Stacking a timing box such as a Comp on top of a tuner that does timing as well is a bad idea. Either one is advanced about as much as the engine can take, and if you put them together the timing adds up. If you feel the need to throw a Smarty in the mix, you'd need to run one of the non-timing programs. But that would negate one of the great selling points of the Smarty. Mix the Smarty with a non-timing box such as a TST Powermax though and you'd be good to go.

This isn't quite true--I'm running a Smarty along with my Edge Comp (with the pump wire tapped) and the extra timing advance doesn't seem to be a big deal at all. What I have seen is that the "mileage" setting on the Smarty doesn't give me any better mileage over the the lightest setting that includes timing advance. I do hear sharper engine rattle and reduced exhaust noise, so it's definitely advancing the timing, I just think it's reached the point where there's no benefit, and perhaps it's at the point where it's any more advance would be detrimental. That's my gut feeling anyhow, for whatever that's worth. I believe I've got mine currently running setting #5, which is the "soft" catcher software plus timing advance.

The fact that the injectors in my truck are fairly mild probably plays some role. JR2 (hasn't been active on TDR in a while unfortunately) has the same Smarty/Comp stack, but with much bigger injectors. He's told me the "mileage" setting decreased performance somewhat and really increased smoke, so bigger injectors may act similar to a timing advance by themselves, but I don't honestly know.

While I expect the extra timing advance of the Smarty/Comp stack probably increases cylinder pressures quite a bit, my stock head gasket has been holding fine for about five years now. I haven't even retorqued the head bolts. Studs might be good insurance just for peace of mind.

It would be interesting to hear from more folks who run a Smarty stacked with a Comp--my experience is only a single data point so I'm not sure how relevant it is.

Mike

 

[JR]

Timing is controlled by an internal timing piston attached to a cam ring. The timing piston is controlled by fuel pressure. The amt of fuel pressure in the timing piston is controlled by a solenoid valve. As pump speed increases so does the pressure in timing piston assembly. The timing solenoid valve which is controlled by the vp's ecm varies the pressure to allow the timing piston to move. Essentially, the higher the pump speed, the more the VP is capable of advancing. Boxes can alter this without necessarily increasing engine speed. There is a point where timing can be too far advanced and once the spray pattern starts detonating outside the bowl you risk melting a piston. A real possibility when stacking boxes under the right circumstances. Even Smarty recommends against heavy towing when using the economy mode because it runs very aggressive timing in that tune.

 

[PC12Driver]

The Smarty/Comp stack results are pretty well documented. Yes, there is a perceived bottom-end improvement, but the dyno and 1/4-mile times consistently show a drop in power. Basically the stack crams 4" of pedal travel into the first 1". It feels like there is more power because of this, but it isn't there.

There's a good chance the cruise control would be useless, since the twitchy throttle response will cause it to "hunt."

Mads recommends against towing with the "mileage" program due to possible engine damage with the advanced timing. The stack is beyond that.

Excessive timing advance in our engines will cause significant wear in the main bearings. A while ago there was a thread with pictures of egg-shaped bearings with excessive timing advance as the suspected culprit.

So, based on the above, that's why I said it would be a bad idea to stack 'em. It's a combo proven to make less power and accelerate engine wear. But folks do it because it feels more powerful. It all comes down to what a fellow would consider a good idea or a bad idea, I suppose.

You are correct about the injectors and their effect on timing - larger injectors fool the ECM into thinking the engine is under less of a load, which also advances the timing a bit.

 

[VolsFan]

BlitzkriegSSII, my truck has about 187k on it. I cannot say what it's avg mpg has been as I have only owned it for a yr and 7k miles. Since I have owned it, it has been around 15.5 mpg, but since adding the comp it has improved. Also, was thinking about a turbo swap but would I be able to use my exhaust brake with an aftermarket turbo?

 

[PC12Driver]

Your exhaust brake will only mount to an HX-35 hot section. So that will limit you to a larger -35 variant (like something fro a '97 truck) or a hybrid with a -40 compressor and a -35 turbine section. Keep in mind that the powerband moves with the turbo - so be ready to give up some bottom for the top.

Or... Swap the cam. All the benefits of a step up in turbo size plus a bit more bottom end punch. And you can keep the exhaust brake. Probably about the same price, too (cheaper for diy).

 

[Sticks]

...Or... Swap the cam. All the benefits of a step up in turbo size plus a bit more bottom end punch. And you can keep the exhaust brake. Probably about the same price, too (cheaper for diy).

Cam, Gaskets, Tappers, Fluids...I don't know that even DIY is cheaper - And that is an awful lot of work. Cam swap is no small job. 13.8 hours flat rate. $600 for a regrind, to $1220 for new for the cam alone.

Sell your current exhaust brake and get a down stream one - I'd recommend US Gear D-Celerator, but there are others out there as well.

 

[PC12Driver]

Cam = $600 (regrind) to $1,200 (new), tappets = $160/set, no gaskets required. A coolant change wouldn't be a bad idea anyway if it hasn't been done recently.

-or-

Turbo = $1,500+, inline exhaust brake = $1,300.

That's about $1,400-$2,000 less for a cam, DIY. Even at a shop with a $100/hr rate it would be a wash. You're right, it's no small job. But there is nothing technical or difficult about a cam swap. The biggest challenge for me was swapping the cam gear, which I ended up taking to my local engine shop to have them press it off and on (shoulda done that to start with). Besides, I could think of a bunch of other things to do on a 12-year-old truck in the process (clean the radiator & intercooler fins, replace radiator hoses, belt tensioner, belt, and water pump, retorque injector hold-downs, etc). This would also give the opportunity to clean the grime off the front cover and re-seal it. And since I was in there, I'd also put in a set of head studs for $450. DIY, it's probably a weekend's worth of work at an easy pace.

I ran 100hp sticks and an untapped Comp in my '01 with a stock turbo and a Scheid street cam, probably around 375hp. I could barely touch 1,350* empty with a sustained full throttle blast. Egts weren't an issue for towing either, without any extra shifting like I needed to do with my HTB2/12.

And even if 400hp+ is the goal down the road, a cam is still a great addition to the engine to offset the shortcomings of larger turbos.

And don't fear a regrind - I ran mine for around 80k miles and the valve clearance didn't change.

 

[jkidd]

If you have a flanged outlet on your exhaust brake instead of the direct 5 bolt mount to the turbine housing you can use the new K27 that is available. it is a 60mm Billet compressor and wastegated. It will work with a flanged exhaust brake and be a nice upgrade for under $1000. It is used outside of the US where cummins and holset are not married by contract. It is used extensively in the brazilian market. Testing in the states has proved nice. consider it to support slightly less than a super B.

A cam and gasket matching on the exhaust can make a nice difference in spool and egt. Not much to see with peak power, but you will have a wider power band. New cams (cummins UGL can be had for about $600)

 

[PC12Driver]

He's got a stock turbo and a Jacobs brake - it's a 5-bolt.

 

[VolsFan]

PC12driver, you are correct. A shame because this K27 kit jkidd describes sounds ok, nothing too crazy and under $1k. Oh well. Performance is decent now, I am unsure how to tell whether or not the turbo is still in good working order. It is a gold color on the exterior, unlike the hx35 on my old truck. No fins are damaged and I can't detect shaft play. I try to control smoke as best I can, revving up higher in the rpm band, 3x5 isn't too terribly bad, but I have heard that a weak turbo will contribute to a lot of smoke

 

[Sticks]

Well I gave the 3x4 setting a try, and my mileage dropped 2.5 mpg. Back to 1x1 and I pulled 15.7 mpg on the last 350 miles, all but 40 of it were surface streets at 48 mph peak speed. This is with the truck plugged in overnight and a 1 minute warm up, and a 2 minute warmup after work. I just drive easy (rpms under 2k and slow accelerations) until the engine temps hit 160.

Morning commute is not terrible, I only have to stop for 6 stoplights, most of them I can roll through (READ - decelerate and it's green before I drop below 10mph without annoying anyone behind me), and maintain the speed limit. Evenings however are a challenge (don't drive angry ) and am guaranteed a minimum of 10 stoplights and 10 to 15 under the speed limit .