5x14's vrs 7x12's

[turbo2387]

Just went from dap 5x14's SAC to dap 7x12's SAC injectors. POP is 290 bar


After much searching i decided to try a different injector. I really wanted 5x16's but got these at a very fair price and the internet world seems to agree they are in the same catagory as the 16's

The are on a cammed, compounded 1995. Estimated hp is 600-700hp until dyno numbers come again this spring. Big hp spread with lots of tinkering until then.

The 5 hole injectors ran great. 60ish lbs of boost. Absolutly no smoke at boost. They had very good street manners. They did haze, and they did it all the time. Overall i was very pleased with them. I chose to move up in injector so i had more to tune with.

60lbs of boost.
32 from primary
1300* wot egts
600-700 cruise egts
900* brisk acceleration egts
Cross section .ooo769

The 7 holers immediate unexpected difference was that the engine ran quieter. The box of marbles was noticably quieter. Unfortunatly the butt dyno was identical. Which i ultimatly expected. Cross section area of the 2 injectors are nearly identical. And the 12's are way under what a 5x16 is. I was hopeful the internet was right. Alas. They still haze but less. Normal driving does produce more smoke. The turbos seem to start talking at a very similiar rpm. At 17psi over all the big one is ready to do work and lights fast. WOT smoke might..... Be a touch hazier leading one to believe there is a little more fuel to work with but its clean at 60lbs.

60ish lbs of boost
32 from the primary
1400* wot egts
6-700 cruising egts
900-1000 brisk acceleration Egts
Cross section .ooo794

All trucks are going to run different but imo a
7x12 is equal to a 5x14 which is going to make a
7x14 much closer to a 5x16. The interweb seems to think differently

I do believe this truck runs better with these new injecters. Its smoother. I do have to do some afc tuning to get these things talking a bit better, so there is a little more on the table. My opinion on these 2 injectors is that it will come down to personal preference to make your decision. Performance on the butt dyno is extremely close. 65moh to 105mph happens in about 2.5 seconds.

 

[Badbrad3701]

What's ur turbo set up ?

 

[jasonc]

It sounds like the higher pop pressure injectors made the engine act like the timing was lowered, they get quieter with less timing. What do you have it set to now.

 

[turbo2387]

62/71 over box 475. Timing is at 17* its been there for about 4 years.
Injector pop pressures didnt change.

 

[jasonc]

You ought to try more timing, assuming your head is o-ringed and all that. I like at least 20 at a minimum.

 

[turbo2387]

Will probably end up right at 20. The truck still tows heavy so i cant get too crazy. I found a cool air cooled VW valve spring laying in a drawer. Going to do some AFC tuning today. See if i can get these new injectors to talk better.

 

[turbo2387]

Results for the day were. After pulling the 100 plate and installing the heavy power driven spring. Boost did go up to the 65 range. With nearly 40 from the primary. Yhe sweep of the boost gauge clearly has two stages in it now which i DO NOT like. Before it was a very smooth sweep. Smoke is noticably more teenagerish. But we found some hp up top. Ive tan into a coil bind situation with this aftermarket spring. With the extra coil i cant adjust the star wheel much at all or the foot wont get out of the way.

 

[turbo2387]

Heres what i ended up with on the afc spring. I had no adjustment with the aftermarked. The custom cut vw valve spring allowed for some adjusment due to it only having 5 coils instead of 6.