The 7's are slightly large for a single turbo in that class. Unless Nitrous is planned.

A 6 to a 6.5 is about the best choice for a single like a 66. That was a great dyno comparison. I rate the 7's at 240 HP, but twin turbos are really better suited, IMO.

Awesome job!

Don~

 

We will put the OEM's in next weekend and run it again, back to back with the honed tubes...that way we can have a true comparison also (no weather, air, lunar, solar etc changes )

I'm glad its only the tubes and not having to swap the sticks again!

 

I can imagine that twins would put more area under the curve getting more air in there early on, but would the peak numbers be close to a single because the Silver Bullet cleaned them up to nothing? Not even a haze from the stacks on the dyno.

PS- We had a 3rd gen with Flux3.5's and twins on the rollers saturday and even when the twins spooled he wasn't cleaning up those flux's...wasn't until the spray hit that it got clean...and the sleeper really came to life

 

Excellent post... nice numbers btw...

I assume the TST box doesn't add timing? Are you running a stock thickness headgasket or 0.020 over? Any issues with too much timing running on the street (low rpm under a slight load)?

 

Looking at the graph Torque is a good way to tell how the engine spools the turbo with the fueling it is given VS the airflow it has. Even on a light DynoJet roller.

At 3000 RPM the 7's are roughly 54 ft lbs higher than the DDP 250's at the same 3000 RPM. But on the other hand at 2750 RPM the DDP's are roughly 25 ft lbs higher than the 7's at the same RPM.

This is a clear indicator the 7's are slightly large for the airflow given. They are running rich of stoich until 3000 RPM. ON the street of course, the turbo will spool better.

A Mach 6 would push it consistantly over 600 using that single and bring the TQ in faster in the RPM band.

 

Thanks for doing all that wrenching for us GB and dzlfarmboy for the use of the dyno time.

 

On a side note...dont try to change injectors on a motor 20 minutes after making 6 dyno pulls...the motor is hot, and my fingers don't like hot stuff. I have the blisters to prove it.

To make matters worse...I did it not once...BUT TWICE in the same day, no more hot motor injector swaps for me.

 

Great review, good job keeping the variables as close as possible.
Did I read that someone prefers doing it on a hot engine (easier because it has expanded?) Doesn't sound like fun to me tho

 

maybe a "warm" engine, there was a steady cool breeze blowing so a slightly warm engine wouldnt be so bad...but these were 180* when i started...very very hot!

 

Guy up here in canada put down 700 on #2 only with his 24 vavler....he had hrvp, redline/juice, mach 7's, and i beleive he was running twins.

 

Thats alot, they corrected numbers?

 

I wish i had my t case fixed before Sat nite, I would have like to thrown Tj's DDP's in my truck to see the difference in two trucks.

 

dzlfarmboy, are the numbers in your sig with Mach 7's and spray? What were the fuel only numbers?

 

Yes, he made 530-something on fuel

 

Yes Mach 7's , NX 2, 88 jet and 136 jet. On a Pro Street 66. My fuel only numbers were only around 530hp. So im thinking 3 things 7's might be to big for a single, or my Pro Street dosent perform as well as a Silver Bullet 66. Or I may have some worn out rings due to high EGT's. I will be doing a compression & Leak down test on it this week.