Twin Turbo Accell DFI Vers Holley 950

[JND]

Hello all, i have been working on a SBC with a twin turbo set-up for 14psi, i currently have a Holley stealth with 950 pro injection set-up with narrow band 02, this is the set-up i was running when naturally aspirated worked great. I added turbos 55lbs injectors and 2 bar map, now i have been unable to get the engine running right, running real rich smoking etc... I have been told a wide band 02 is required for tuning any forced induction engine. Holley make a wide band add on kit, however i have also been told that Accell DFI genVII is a better set-up.
Has anyone run the Holley 950 with boost? is that the right way to go or convert to DFI?

Thanks for any input.

Thanks JND

[ProdigyCustoms]

I have converted a few Holley system to FAST XFI. For your need, I would suggest a FAST or DFI, they are both excellent. I am familar and sell FAST, so FAST is what I use. Also, the FAST will be a little cheaper then a XFI.

[camcojb]

I would highly recommend a wideband for any forced induction system. I do not recommend the Accel DFI for any beginner tuner, it's a bit tricky to tune in my opinion.

Love the FAST system.

Jody

[64duece]

The suggestions are correct, a WBO2 is a very useful tool in tuning any EFI application, especially with a boost. I still recommend reading the plugs (all of them), and EGT's if available.

Put a WBO2 on it and plug away. I've heard the "Cmdr950 needs to be upgraded" story too many times. It has more than enough control. You don't need a Gen7 or FAST.

I've gone 7.60's @ 180mph with that same box and 28lbs of boost. I've turned it down and it's consistent enough to go 8.51 back to back to back to back. Many tuners aren't familiar with it and usually steer away from it as the FAST and Gen7 are more popular and in some applications do offer advantages but, it's no reason to upgrade in your specific case.

[JND]

I will give the 950 another chance with a WB02. Thanks for the information.

[Z-man]

I'm running a supercharged SBC and a C950 with wide band O2. It works great and wouldn't think of running with narrow band. The WB will give you much better control. :thumbsup:

[Diesel77]

Are those the Ebay $200 SBC headers made in China??

[JND]

Thanks for the info on the C950, i knew i had to go with a WB02, but did not want to buy it if the C950 was not a good system to use with boost. Not the case, i will but the WB02 kit. in the mean time I did try to tune with the NB02 and i am assuming due to the fixed A/F ratio i can not get it to run crisp, seems to run real fat at idle.


No china headers here, i made this set of headers from 2" mandral pipe. I can't imagine what you get for $200.00, It cost me $200.00 just to have mine ceramic coated.

[Z-man]

Thanks for the info on the C950, i knew i had to go with a WB02, but did not want to buy it if the C950 was not a good system to use with boost. Not the case, i will but the WB02 kit. in the mean time I did try to tune with the NB02 and i am assuming due to the fixed A/F ratio i can not get it to run crisp, seems to run real fat at idle.


Yep - most folks running boost suggest not running NBO2 due to the lack of control of the A/F ratio. With a turbo, you can go lean mighty quickly during the tuning process (even if you're rich at idle) and risk burning up a good engine...

[JND]

Thanks Z-man good to know the c950 can handle boost aplications. Do you run a timming boost control, or are you using the spark Map to assign timming advance for certain loads.
I checked out your pictiures on your Vette very nice set-up. I always liked that body stlye.

[Z-man]

Thanks Z-man good to know the c950 can handle boost aplications. Do you run a timming boost control, or are you using the spark Map to assign timming advance for certain loads.
I checked out your pictiures on your Vette very nice set-up. I always liked that body stlye.

I just use the spark map to assign the timing. We experimented on the dyno to get what appeared to be the best. You can also have the spark set back during cranking so it starts easier, but I've got pretty low compression so I haven't fiddled with the standard settings.

The C950 can adjust fuel based on boost. It also has adjustable settings for a knock sensor if you're worried about knock. On my MSD ignition box I have ignition retard at high rpms for boost or nitrous. I guess the spark control just isn't as important to vary with boost as the fuel is...