Hey all,

I finished up my injectors from R&D a few weeks ago and my plan is to have a new IP in by 4th of July.

My goal is to have a reliable & strong truck that doesn't guzzle fuel. I want to buy quality parts, that's why I am going through Justin. I picked up a JY turbo off a 94 idi that still needs to go in this summer. I will probably do head studs when I finally pull the engine, but that's not clear when. I will probably run and intercooler, and upgrade the turbo with a new wheel or whatever else I can do.

But most importantly I don't want to spend a ton of cash on something that will make my blow through fuel. Can someone explain if I buy rd4-150 or a rd2-80 or anywhere in between does that mean I am going to be killing my mileage? I understand it is all in the pedal, but if I am putting more fuel in at 2800 rpm then I am burning more fuel, also how is the curving different?

Devin

 

Oh and if I do get a ip that requires a turbo, head studs and an intercooler, can I turn it down a couple flats until I install all those pieces?

Devin

 

I got n/a .. so someone with a before after turbo would know better ..

But i get my best fuel economy 1,300 to 2,100 rpm .. and i understand most turbo's aren't really spooling alot on the bottom end .. so i would think they would want to kinda stomp it to build pressure and get it into the powerband .. totally a guess as i never driven a turbo idi ..

As a matter of preference i like down low power and torque .. and good fuel economy .. so if i ever did do a turbo on a dd it would be a smaller quickly spooling one .. at the expense of some top end hp .. i think justin did a writup of the turbos an d if memory serves a little one number 256 i think looked pretty cool .. but i admittedly have strange taste ..

My reasoning would be likely flatter fuel curve .. off line grunt .. decent milage .. but probably won't build more then 10 -15 psi but would do it quickly .. that said .. i was just musing and overall i like my engine power .. sound and economy .. so not gonna turbo it .. i think a n/a would get better milage ..

In theory a turbo could get hypothetically better milage but i don't see it in what mpg numbers people post .. but you can drive fast so i do see the appeal ..

 

Effectively, yes. The 110CC ones are just standard DB2 pumps, so should have the screw... I think. The larger ones, I don't know. You can always be very light on the throttle, but my 110CC was quite sensitive at the low end(until I got an Aneroid to limit fueling; now it's perfect).
Without a turbo(or enough of one), you will just get black smoke instead of high enough pressures to blow a head gasket; you need the extra air in there to get enough pressures to need them. And you can even run a mild turbo(10 psi or so) before needing the studs.

 

With a "stock" turbo, i dont see the justifacation in going to a 110cc. Not throwing macrobb under the bus intentionally, but his setup is a good example of the limitations of the stock turbos. The 90cc is capable of 240whp in an optimized system, the 110cc is capable of 300whp.

 

I would not go over a 90cc on a 6.9 unless you decompressed it with piston shaving. There have already been examples of 6.9's WITH head studs blowing head gaskets on 90cc's of fuel and BW 256 turbos. RD2-90 is a good companion for the factory turbo kit. Get that and really consider ARP head studs for peace of mind and the ability to get the most out of that 90cc safely.

 

Is it safe to say I am never gonna get enough combustible fuel into the cylinder to push my EGTs out of a safe range with out a turbo?

Does extra cc's of fuel just represent more unburned fuel (IE no additional heat production). ?

Is the fuel curve the same? Can I just turn the 110 down to mimic the 90?

Devin

 

Oh and how does the fuel curve compare to my stock IP, like does the R&D pumps not pickup until higher RPMs? So until I put my foot down on the throttle it is mostly the same?

Devin

 

The opposite, the bigger pumps dump tons of fuel whenever you press the throttle, so even just above idle giving any throttle you can produce black smoke lugging the engine. I have the factory turbo with a wicked wheel, banks down pipe, full 4" exhaust, a Bull moose with misters and an intercooler and i can see a puff of smoke just letting the clutch out or giving any more than say 20% throttle when taking off and accelerating it'll send black smoke. The turbo helps by adding more air but without boost/air the pump is still going to deliver the same fuel because it doesnt know, all it knows is throttle position. I couldnt imagine run that big of a pump without a turbo. I think the bull moose is a 100cc?

You will get your EGTS over 1,000 just lightly accelerating without a turbo. Turbos help by "diluting" the exhaust gases with cooler air and by adding additional oxygen so the combustion takes place in the chamber. I would say you can't run those pumps (110cc) without a turbo, and you shouldn't ideally without an intercooler. I wouldnt adjust anything, just wait and get the right pump at the right time.

 

Also if I decide my 093 is not enough for my needs, can I design a system (intercooler, down pipe, etc) that I can swap in one of Justin's turbos with out having to redo everything again?

Devin

 

Justin just yesterday put one of his stage 1 turbos on a 093 exhaust housing. It will be a direct drop in to replace the Garrett, it even works with the factory hat. As soon as he gets the wastegate linkage figured out the option will be available for sale. This will replace his rebuilds and Garrett upgrades. The stage 1 turbo flows 65 lbs/min. and is enough air for a 110cc pump. It should be good to about 350 horsepower. It is a great turbo, and anything you fabricate as far as an Intercooler on the 093 Garrett will work exactly the same way with the stage 1 drop in if you upgrade later.

 

I would ask Justin about turning down a bigger pump if you want to temporarily run it before you install the turbo. In theory you should be fine as long as you keep a *very light foot and watch your smoke and EGT's. Don't even try it without a pyrometer. You most definitely can deliver enough fuel to F stuff up while NA. The higher fuel delivery of the big pumps is across all rpm's... my RD4-150 calibration sheet says my pump can deliver 222cc hot cranking at 100rpm, 192cc at 1,000rpm, 180cc at 2,000rpm, and 157cc at 2,800rpm. That of course is max flow with the accelerator floored.

If you are thinking about the 110cc and a higher flowing turbo than the stock Garrett, I would ask Justin about the prototype decompression head gaskets. Prior to install they measure 2.8mm and should lower the static compression ratio to ~18:1 without having to shave the pistons. That is the only way I would run a pump that big on a 6.9 (and with studs obviously). Some guys have been lucky and have gotten away with quite a bit on 7/16" fasteners, others have had HG problems at rather disappointing power and boost levels. I just would not take that chance.

 

But is the argument that I can have these big performance pumps and control my throttle with a light foot even accurate? or beneficial? I like the idea of having power when I need it but on the other hand I don't want to dump money to find out I am burning fuel out the tail pipe as black smoke or HP I am not using.

Devin

 

It also looks like all the pump up to the 90 are the same price, so I imagine they are all the same other than the calibrations. Is the calibration just the fuel screw? Could I buy say the 80, then dial it up to the 90 later down the road or are the calibrations more advanced than that? Could I do the same with the 110?

Devin

 

There is a lot more to the calibration than just the fuel screw. The bigger pumps are calibrated for turbo use and take boost into account. There is no point at all in buying or running an IP that delivers more fuel than you can burn. If you need a pump now but can't afford the turbo you want right away then you can probably work around the over-fueling until you can afford the better turbo. But if your turbo plans are vague or distant, then right-size your pump for the air you have. If you have an 093, it can supply enough air for a 90cc. If you get, lets say the stage 1 turbo down the line, you will still gain over the Garrett because it is more efficient but it will only take you so far with the fuel you have. In general it is better to have an overkill turbo that will supply plenty of air than an overkill pump that supplies too much fuel. Really think about your future plans before you buy.