Dynojet afc tuning

SCHMITTY

SCHMITTY

Not enough time
Joined
Jun 20, 2012
Messages
1,190
I'm going dyno my truck for the first time and its on a dynojet 248. The guys that run the shop want to dyno it in od.

I have a lock up switch
4.10 gears
200 rpm lower than stock converter
No fuel plate
Rack plug
Washers ground, foot ground
He351cw
16.5*

Now the truck barely let's out a puff when I floor it from a dead stop but it will peg the 1600* pyro by 55 mph. I have the wastegate hogged out to 1 1/16th" and I'm hitting 42 psi on the street.

The shop said they have a hard time loading trucks with the od turned off and I was just wondering if I should loosen the afc up a bit and tighten wastegate/spring gate down for more boost. Would that help the truck spool on the dyno ? At about 1800 Rpm's on the road it lights real quick.
 
Why would you not dyno in OD?

You should dyno in OD with the converter locked. With a stock sized turbo I doubt you will have any issues getting it to light, but I doubt you will see anywhere close the 42psi you see on the street on a no load snap.
 
If I adjusted the wastegate for higher numbers say 48-50 psi do you think I would be able to get closer to 40 psi on the dynojet ? I'll see if they let me tighten down the spring gate after the first pull
 
SCHMITTY said:
If I adjusted the wastegate for higher numbers say 48-50 psi do you think I would be able to get closer to 40 psi on the dynojet ? I'll see if they let me tighten down the spring gate after the first pull
Click to expand...


It's not the Wastegate setting, when there is relatively small load, you don't create the EGTs necessary for full boost (cylinder temps stay relatively cool)


Sent from my flashscan v2
 
Unless you ride the chit out of your brakes but even then its tough to see full boost.
 
Thanks for the help everybody. I got a call yesterday and they bumped my dyno appointment. The shop is behind they said. I scheduled it 3 months in advance !! Damn. Guess the 1/4 mile trap speed will have to work. But the track does not open until Memorial Day. Hopefully I don't break something on the truck before then. Trying to break into the 13s
 
Weigh the truck right before or after you make a pass and get a trap speed. That will be a waaaaay more accurate rwhp number
 
In my sig ... my truck also will peg out the pryo at 15.5* of timing ... I need a larger turbo and more timing as well ... what all are you running

what pump ?

I was told running in 3rd gear in lock up was 1:1 and would be a better run on they dyno ... or find someone who has a dyno like ... the unit we all punish our trucks with here in the NW ..

Source Automotive in Clackamas Oregon ... Know as the punisher !!!!
 
The track doesn't open up here until Memorial Day. I scheduled the dyno so I could at least have those numbers in case I break the truck before I can make it to the track. I was going to see if I could make it into the 13s with 5x10s and 16.5* timing. I might bump the Timing 22-26* with retorqued head bolts depends on if I get time to do it before I can make it to the track. Same goes with injectors, I might throw some 5x14s on before I go to the track all depends on when I start working some more OT so I can buy some new injectors. I have the afc setup better now and what a difference that made !
 
Good tuning of the afc can really help with spool, i see a lot of 12v dyno video's and they are just burring the charger in fuel and it kills power until it can get on top of it.
 
DieselMonster said:
In my sig ... my truck also will peg out the pryo at 15.5* of timing ... I need a larger turbo and more timing as well ... what all are you running

what pump ?

I was told running in 3rd gear in lock up was 1:1 and would be a better run on they dyno ... or find someone who has a dyno like ... the unit we all punish our trucks with here in the NW ..

Source Automotive in Clackamas Oregon ... Know as the punisher !!!!
Click to expand...


160 pump -30 psi fuel pressure wot, 42 lbs of boost the rest of the mods are in the first post.
 
Joesixpack said:
Good tuning of the afc can really help with spool, i see a lot of 12v dyno video's and they are just burring the charger in fuel and it kills power until it can get on top of it.
Click to expand...

I stretched the afc spring , and went through the basic adjustments. I'm sure there is still room for improvement.
 
I personally like my truck to make near no smoke and good HP... torque will come with tuning and timing ....

Add fuel = add some timing
high egt's = need more turbo

thats my issue , too much fuel and not enough turbo ..

So if i adjust my wg ( currently goes to 26 psi ) .... would this help with the egt's ?

I did think about backing off the fuel and bumping the star wheel to compensate for the less fuel ...
 
If you have head studs I would be running higher timing already and more than 26 psi boost. Do you have gov springs yet? Or cranked down the stock ones? I would think any mods you do to the truck are not going to net you much gains without uping the stock governor settings, aside from making it hotter and smokier without gaining much power.
 
it does have 3200 gov springs , just curious if loosning up the wastegate to allow more boost will help or be a bad thing ...?

And yes i need to time it up to around 18* minimum here real soon
 
For dyno, always run in OD locked. You can feel the difference on the street/track, you'll see it on the dyno also. And if they won't load you up on the dyno, you'll need all the help you can get. Overfueling a little will help get EGT's up also if they won't load you.

For dyno runs I put afc all the way forward unless you're already way overfueled, and tune down the low end fuel some so you don't choke it. Or start the run at a higher rpm. Bump timing to 18* at least if you have studs or tightened stock bolts. If your drive pressure is safe, crank that gate down as tight as you can without pushing the turbo past its limits.
 
I dont know what the drive pressure is but , HX35W on a 215 W 887 pump stock, with out the fuel plate , they (DDP ) siad it would be way to high ( like 60#'s ) , I been looking for an auroura 3000 , or a silver 62, something along these lines ..

She tows and goes down the track , just a tune away from either ..
 
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