chadder1313

With stock turbo and Injectors what are the best dyno numbers with an H.O. Also i am wondering if the injectors that TST sells on the website are worth buying and running.

Canamboy

I have 100hp injectors in mine and with the edge comp the mechanic i bought it from said i was pushin 600hp with the stock turbo though i dont think im close to that since i have stock turbo im prolly around 450 or so maybe more.

AggieJustin

2001 HO with an Edge EZ, DD2s (90hp) and a stock turbo put down 345hp consistently.

Replacing the EZ with an Edge Comp bumped it up to 373hp (only one dyno run).

Switching to the TST/Smarty stack and the KSB1-1 got me to 423.

HOHN

Ha, that's funny. Canamboy, you're pushing more like 390hp-- maybe 400, depending on injector quality. It could be as bad as 350hp

With a stock turbo and injectors, the most power you can get from an HO is right around 325-335hp, give or take.

The factory HO injectors are tiny-- even smaller than the SO injectors.

If TST is selling RV275 injectors, they are a pretty good, mild upgrade-- they'll add 40hp or so to an HO and help mileage in some cases.

To make the most of those injectors a boost elbow or regulator of some kind will help. The computer on an HO will allow up to 26psi or so, and that's plenty to cool the 275s except in extreme high altitude and/or hot weather (like, Death Valley hot).

jh

chadder1313

Well i got two pulls on a mustang dyno back in October and it put down 305 HP and 610 Ft. lbs TQ. That was with out a boost elbow and about 26 psi. I just recently installed a boost elbow and i have it adjusted at 35 psi. It made a huge diffrence. My next step will be a set of RV 275's. I was just curious as to what the H.O.s were capable of with stock injectors and turbo.

Philabuster

OK, I need a bit of clarification here.

I have read that the RV275 injectors are smaller than the stockers (SO? or HO?), but they burn cleaner or have better spray angles, thus giving a bit of mileage and performance boost. True or am I reading a bit of misinformation?

Another question: Will adding a box (yeah, the Adrenaline!) 'hurt' the VP44 by trying to push the fuel through such tiny stock HO injectors? Is there any benefit to installing SO injectors or don't bother and do the RV275 at minimum?

I almost have my mind made up on the Mach 4s, but even those injectors alone will destroy my clutch and require a turbo upgrade for towing 10K lbs. Perhaps I would be better off going to the Mach 1.6s for use with the Adrenaline because I will be towing a trailer once in a while.

It's only money.

AggieJustin

The RV275 injectors are the stock injectors used in the 275hp version of the Cummins used for RVs. They give a mild horsepower boost, and pretty much any injector is better for the HO than the stockers. You typically get closer to (or exceed) the quoted HP gain of an injector with the HO vs the SO.

It's not that you're hurting the VP44 by pushing fuel through small injectors, it's that your increasing the duty cycle of the VP44 which can have an adverse affect. That's why injectors are usually considered to be easier on the VP44 than a box. Instead of holding the fuel open longer, you're pushing more fuel during the stock injection cycle.

The M4s definitely will require a turbo upgrade for towing 10K. And I've heard nothing but good about the M1.6s. And with the Adrenaline, you can turn up the fuel to play and down to tow so you can keep temps in check.

If that's the case, can I send you my address for a check??

HOHN

Phil, I haven't heard that the RVs are smaller. I find it hard to believe because they will add a good little bit of power with no mods that increase duty cycle (electronics). I also can't think that a spray angle improvement would net such a gain at LOWER flow. That would mean that the regular HO/SO injector are way off, and the Cummins engineers are better than that, imo.

AggieJustin is on the money on the VP duty cycle.

OK, now I'm going to say something that may endanger my credibility. The M4s won't necessarily thrash your clutch, nor will they require a larger turbo.

I ran M4s WITH a catcher ECM for months before my stock clutch showed any signs of slipping (the change from thin air to sea level did it, I suspect). The type of electronics you are running has a MUCH larger impact on clutch life and EGTs and such than does injector size. If I wanted to, I could destroy a stock clutch with just a Smarty/Catcher and 275s! A lot of it has to do with how much tq is being applied when the clutch is engaged from idle, and this is much more affected by electronics than injectors. The electronics increase the gain in the idle governor circuit which dumps in a LOT of fuel when the engine is pulled below idle speed (such as clutch engagement) and applies more tq to the slipping clutch. In other words, the engine fights much harder to maintain at least idle speed. This means that with more aggressive electronics (Smarty on 9, say) each launch from a stop is almost like catching a moving train, and hard on the clutch and tires.

With stock software in my truck, it's actually very docile even with M4s. The experience at each stop light is very different. Instead of sitting on a mountain of torque that blasts the clutch and tires when I engage the clutch, the engine will actually "give" a little at launch. I can actually kill the engine with a 2nd gear launch of I try. I can't do that with the Smarty SW (5-9), as popping the Con FE hard will just result in a huge impact to the trans and tires, and won't kill the engine. It's SO aggressive, in fact, that I don't think I could kill the engine with it idling in 1st gear by applying the brakes as hard as I could!

So I'm convinced that M4s could easily co-exist with a stock clutch, IF (and ONLY IF) mild electronics are used-- stock software or a timing-only mode of XZT+, for example.




ON the towing issue, I will just say that it's very easy to back out of the pedal when EGTs get on the warm side. At the turbo's towing EGT limit, you'll be putting about 350hp to the wheels, even though the M4s are capable of substantially more.

If anything, I'd *recommend* the stock turbo for a largish injector like an M4 (IF the driver is responsible) because the fast spoolup really helps keep down smoke.

To me, it makes for more sense to limit fueling when towing than to buy a larger turbo that MAY drop some egt but will also be slower to spool whether you're towing or not (meaning more smoke).

10K doesn't need more than 350hp to tow, imo, and your HX35 will make 350hp when you need it, and spool really fast when you don't.

I've been running M4s with the stock turbo now since the summer of 2005. Never had an EGT problem running empty in density altitudes of over 12000 feet (6K elevation plus upper 90s temps).

IMO, the ONLY reason to go with something smaller than an M4 is if you're trying to squeeze every last MPG drop out and even a couple tenths matter, or if you have a new white RV that you don't want all sooty. The M4s will soot up a clean trailer, because even though they don't "smoke" all that bad, they do leave a haze when cold and sometimes under light load conditions.

M4S are cleanest when run under load with a warm engine.


JMO

Philabuster

Thank you both for your input.

My wallet is going to get thinner again.

chadder1313

Good information HOHN.

seth08

600 u got to be kidding me

oscaroc

I agree with HOHN, M4's are very drivable. If a guy was "responsible" I do beleive you could maintain stock clutch with injectors and little or no electronics.

I ,on the otherhand, walked through my clutch seconds after I buttoned up the injector install, with Edge comp on kill a freeway on ramp, truck in fourth gear and the skinny pedal mashed to the floor.

By the way my Truck Is an SO

AggieJustin

I think that's usually why everyone says that you need turbo/clutch upgrades for M4s. While responsible driving will get you a long way....how many of us are really responsible? I usually turn things down when towing heavy, but there is always that time that you feel it's a good idea to show off a little power and turn it up. That's when things can go south.

Hopefully, I'll soon be able to speak intelligently about how M4s behave in a HO.

MSquare

Fill out your sig! I gotta see what else your running to get that number!




Actually, there is no way on earth your near 600. And if you only have the comp and 100 hp injectors, your probably closer to 375. Sorry for being blunt.

Philabuster

Perhaps the mechanic said 600 TORQUE and the OP thought he meant HP. The dyno run of 305 HP and 610 TQ looks like this might be the case.