Looking at putting fuel injection back on my L98. I am looking at the Commadore 950 vs Modifying my original TPI with an Edlebrock Base and Runners (680.00). I need a new harness and some clean up work. I could buy the Commadore (700cfm) for 1300 bucks that would include an ECM, harness and sensors. Performance isnt my number one objective. Any thoughts on people with a Commadore setup vs modified TPI. I just wondered if a newer TBI system is better than a slightly modded TPI.
Thanks

 

its saturday and your out of town. your vehicle doesnt start.
what do you do... you find out your holley commander has a crapped
ECU.. you call holley. luckily someone says they will ship you an
ECM. mega shipping dollars later, you maybe on the road. as
for TPI.. parts are available easily. most garages work on TPI. if the
holley needs work.. you are now the chief tech for it.
granted TPI has limitations, but what are you really after?
airdeano

 

I understand your point, however I only drive the car about 1000 miles a year. Not to worried about anything other than which system provides better response and performance. Have you heard about problems with the 950 ?

 

I don't know of ANY fast cars with the Holley TBI set-up on them. It's easy to make a port injected car go fast with a GM wiring harness and ECM running it though. And as already pointed out, the GM ECM is cheaper to replace and easier to find in the event something does go wrong.

 

Look at this months Car Craft for comparisons of the Commander 950 with TBI and the stealthram and single plane EFI intakes. It works better than you might expect.

 

If you are looking at a copy why don't you save us the legwork and give us some insight on what they did and how it worked out? I.E. engine combo, what ECM the port injected engines are running, and results?

 

Do a search on the EFI section for the Holley stuff, you should get your answer as why not to use this system.

 

TPI is great for low-end torque, its very streetable with its power curve, povides good fuel economy, and its pretty cheap to build one up to support 350 HP. Commander TBI setups ($1300) cannot be as efficient as TPI or Edelbrock PRO-Flo multipoint EFI units due to the point where fuel is injected: like a carb with big injectors in it. If dollar to performance ratio is the most important factor, TPI is probably the way to go. If best performance is the main priority, the Edelbrock Pro-flo multipoint is the way to go. Its pricey at nearly $2000, but has more benefits than TPI, such as a built in programming unit and also its a sequential fire system as opposed to the less efficient batch fire system on Tuned Port. I really doubt that the aftermarket TBI units are really worth the money being that they don't provide the throttle response, performance, and efficiency that multipoint injection has. Just compare the old TBI injected 305s to the TPI 305s. Advantage: Tuned Port.

 

The advantage of the C950 used with a TBI unit is that you can finely tune the fuel curve, just like a multiport system. You can get a perfect A/F ratio curve easily without playing with jetting, bleeds etc. The distribution is as good as the manifold is, just like carb.

Cold start can also be tuned precisely. Uses a bit more fuel than a MPFI system when cold.

The dyno testing mentioned above shows the TBI was within about 10 HP of a MPFI system on the same intake.

This system also works great on roots blower engines such as the 800 +HP engines I have tuned and come on many $50K+ marine engines.

You also have programmable timing control which is a very nice feature also.

 

The engine dynoed was a very mild 355 that made right about 400 HP.