DTanklage

which works better?

'97 truck with a #10 plate and a s300- ddp stg III inj and get more aggressive with the plate and spring adj

or - ddp stg IV inj with a more consevative plate and spring adj???

see what i am getting at?

how will the two inj work differently when adj as such to same power level?

especially conserned with fuel milage

has anyone tried doing it both ways?

thanks in advance

don

ps - yes, i tow a lot with this thing

22k+

Tate

With the larger injectors, you won't require as much duration (rack travel) to inject the same amount of fuel, so I would suspect you would have better EGT's. Mileage would be a gamble either way. I'd say that the bigger injector might get you better mileage, but its just a feeling, no factual basis from me. If it were me, I'd go for the bigger ones and dial back the plate and AFC if you get too hot, but I also don't tow, so maybe someone who does will jump in.

What size turbo?

DTanklage

right now its a 65mm turbine inside a ported 13 cm s.s. housing

(62 compressor)

got bigger turbos but that one seems to work really good for towing

at the time i had it built htt didnt think they could get away with opening up the housing for the 71 wheel

they have since found out that they were wrong but none of my larger chargers have the stainless housing

don

DTanklage

that was my plan but i thought i would ask in here and see if anyone had tried it both ways and could speak from experience. maybe we are wrong and the smaller inj will atomize better or something. dunno. have run ddp 3's and 4's in other trucks (no p-pump tho) so i know that both are efficent clean injectors

thanks for your time and thought

don

97 D-Tec

From what ive been told when i was talking to a few places about 140s when i thinking of getting them, they gave me a general idea:The bigger the injector the more fuel, and heat will be added period even with the same plate (doesnt mater if its the conservative 10). From my experience A 62 will not need 140hp injectors (i believe thats what the 4s are) inorder to light because its a rather small turbo. So far with my 90s and a number 8 plate ive been fine lighting a 64/71/14 all day long as its my daily driver. Right now im trying a number 5 but it seems it wants to give me a little too much heat up top so i may need to dial it back some.

DTanklage

right. so picture this: your truck, 90 inj, #8 plate full forward

vs your truck, 140 inj, #8 plate pulled back some

thats what i am asking - how would it be different?

i am sure it would, even tho you would have the plate pulled back so that max power is the same (even tho you now have bigger inj)

97 D-Tec

Id probably still have to find away to get it to stop dumpin fuel initially causing me lag n rollin coal. and/ or find away to deal with the heat towards the upper end of the rpm band in od.

DTanklage

i thought pullin the plate back would do both

Tate

Initial smoke = tighten up the AFC, or pull it back some.

Heat up top = pull plate back, or more air, or ignore it, if you're running empty.

65fury

` Hey Don, dont know if you have a gsk yet, but that will help you out alot especially since you have a 5spd to tow with. As far as plate size experience i have little, i used a #4 in my truck but wanted more fuel so i gutted my AFC and modded the rack......ect, but i recently had added the #4 plate back in just for kicks and giggles, and it made a huge difference, i finally cleared up the smoke when the turbo spooled up and egts came down alot. And basically what Tate said is right on, with the afc spring loose you get more fuel at the bottom end and that can build heat up when towing( i know cause i made the mistake of a loose spring and plate forward when towing) but if you tighten the spring you still might be able to keep the plate forward, since you wont actually add that much more fuel until your pushing more boost. Oh and to add to the turbo with the 71 wheel..... they spool up late, they build boost quick, but take longer to spool than the 65 wheel (ive had both)

Jason

97 D-Tec

I know i can do that tate. I meant if that decides not to work. id probably have to swap plates to sumthing else

DTanklage

i have the 4k gsk and am waiting til i feel gutsy enough to install

thanks everyone

65fury

Hahaha, install it! that was my favorite pump mod i did to my truck it makes your power band so much larger.


Jason