Well, my setup is in the sig. I am frankly sick and tired of messing with the carburetor to get optimal performance and optimal driveability. I've spent a lot of time trying to get rid of the occassional hesitation and fix my gas mileage (8.6 MPG on relatively conservative driving). So I'm thinking of the Holley Commander 950 throttle body injection setup (450-600 HP model), since I should have about 460 HP. I have a few questions. How easy is it to tune the 950 at WOT considering it DOES NOT have a wide band 02 sensor? Can I still program my spark curve with the computer since I have an MSD Pro-Billet distributor (mechanical advance and a magnetic pickup)?

My main question is should I throw down the cash for this or should I continue to work with the carb? ANY help would be greatly appreciated. Thanks in advance.

 

Sounds like you're sick of dealing with the Carb. EFI is a good alternative and in most cases there are alot of advantages (like good gas mileage). So you want to go EFI .. the question you need to answer is, what intake design do you want to go with? Once you've decided on that, then think about how you want to tune it.

The ECM is only part of it. You will also have to change all the wiring and the intake itself. The kit you describe comes with a TBI intake. That would work fine, but I recommend you check out what else is avalable before spending money. There are alot of different intake styles out there for EFI and you should choose the one that matches the type of performance you want. In some cases, the choice you make can save you a load of money. In other cases it can cost you an arm and a leg. You have alot of choices, some designed for torque, some designed for top end power. Stock TPI intake, Stock TBI intake, modified LT1 intake, Aftermarket Miniram, StealthRam, Superram, etc etc. Do searches and read about each one to find out which matches the characteristics of your engine and the type of performance you want.

Once you decide on what intake design you want to use, then think about the tuning. Believe it or not, you can do alot of advanced stuff with the GM equipment. It takes alot of time and effort to learn, but this is by far the most cost effective way to tune. Kind of reminds you of working on your carb dosnt it? Tuning your motor (carb or efi) will be cheaper if you do it yourself. But it will also be harder. If your motor already has alot of aftermarket parts and you dont want to deal with learning how to burn chips, tune the car, or do any of this stuff, something like the Commander 950 might be a good choice. The aftermarket DFI units are by far alot easier to use. If you go the DIY route, you might find yourself feeling the same way about your new EFI setup that you feel about your Carb right now. Might be worth it to spend the extra $$ and make it easier on yourself. Just make sure you choose the right intake for you.

My motor started as a Speed Density L98 with a TPI intake and the stock 730 ECM. To compliment my blower and the 6 speed comming, I want an intake design with more top end power (6500 rpm). I've decided to go with the Holley StealthRam. But for tuning, I've decided I want to DIY because I'm a cheap ***. I will be using a 749 Syclone/Typhoon ECM to manage my engine, and I will admit it will take a long time to get it tuned perfect (months). But the end result will be the same as expensive aftermarket DFI, and it will cost less than 1/2 of the aftermarket stuff. The money I save pays for the intake itself.

 

I did it, went from carb to commander 950 TBI setup. you can put it on any intake you want, that a carb would go on.

It can be a pain to tune, but so far from what ive seen / read its easy compared to the GM ECM. if you dont need emmisions (obviouselly you dont) the only reason i could think of sticking to GM ECM or CARB is the cost factor, the commander will run you $1300 complete.

When i first put it on my N/A 355 it took me about a month to really get it running right. i would tune it daily. takes a lot of patience, its real time, so you make a change and save it and the ECM starts using the data. i had to learn to make small changes, i would always overcompensate for stuff...

i will point out the system seemed to do 200X better on top of a blower. all the benefits of EFI just tripled when i put the blower under it. it could be due to the blower or, what i think, the better atomazation from the rotors. i would always smell fuel at stops before the blower, but it was running rich.

yes its better than a carb, if you can tune it. but for $1300~~ you could buy yourself a weiand 142 blower and add 100 horses as opposed to adding a few MPG and some throttle response. IMO there are better mods to spend that $$ on, unless you really really want the controllability of EFI. its great but so much $$$.

how baddly do you want complete control? remember its still TBI, the fuel economy with overdrive and lockup will still top out around 19 MPG after 5 months of tuning (my experience) do you have Over drive and Lockup? those will affect MPG more than TBI. i am switching to TPI (multi point batch fire) to get my 19 MPG to somwhere around 27 MPG with tuning. i will be using the GM ECM with Crazy's help I will get it up and going. i am considering using the commander with it, but i just got happy with it on the blower....

 

Another way to go would be to mod your RPM manifold for injectors & run a 4bbl type TB. This would give you the benefits of the short runner manifold & the precise fuel delivery of multi port. The 950 is available just as an ECU & harness, which how I bought it for the Super Ram I had before. You can still get O2 readings & tune at WOT, it's just not in closed loop.

 

I have a 92 camaro that was origanlly equipped with TPI. I now have the HSR. If I purchase the commander 950 for the TPI version (ECM and TPI style Harness) will I be able to use the stock speedo and tach?

Also I have a SX inline fuel pump that I currently have hooked up to a 12 volt constant, which at the time of installation was a great idea, but in the real driving world sucked. When i'm at idle or in traffic I don't need 85gph, so after awhile the pump will be on full bore and will sart cycling the fuel so much that the fuel will start to aerate and then I get cavation. So my question is, will the 950 control fuel pump voltage in coralation to RPM OR load on the engine, ahla aeromotive's fuel pump controller?

As far laptop computers, can I get away with the newer style laptops? They come with Windows XP and I don't know about com ports?

 

I think your going to need to rewire the speedo. On Z28's the speedo gets it's siginal from the computer. You maybe able to route the signal from the speed sensor strait to the speedo, but don't quote me on that.

 

Hmmm No bueno. Does anybody else have any ideas how to combat this problem?

Paging MR Flynn.

 

for the fuel pump issue what you need is an in tank walbro fuel pump and a regulator. my C950 came with an inline fuel pump and IMO that thing was only loud and crappy to me. it wasnt like it didnt work, i just didnt like the way it pulsed fuel. they have to be mounted perfectly or they wont work right i found out.

You dont want to mess with voltage at the fuel pump really, it can hurt the pump more than help it. some of them dont like to be run below 12V for more than a few seconds. The commander relys on the regulator to stop fuel, not fuel pump voltage. hope your using a return line and a high pressure regulator...

as for the speedo and tach issue, i ripped mine out and put autometer stuff there. the speedo would have worked fine because i had a cable driven from the tranny to the speedo, so it didnt need changing. the tach im not sure, but you dont really want to use the factory tach anyways. right before i ripped it out i noted how innacurate it was.

 

More good news, thank you.

I'd really like to keep my stock dash functions if it all possible.

as far the pump go's yes I do have a return line and a AFPR, but the pump I have is well suited for my application so I guess I'll get the pump controller. I spoke with the SX tech regarding the same issuse of pump life and voltage drop, he said there should be no problem, since aeromotive based their 1000hp pump after the SX pump.

 

You can take the tach wire and hook it back up to the coil or CD box and it should work. A buddy of mine kept his factory ECU to keep the speedo working if you have an electronic speedo. Just keep the wiring to the VSS and power and grounds. The rest of the engine harness could go.

 

IMO most carb problems aren't the fault of the carb, but the ignition, the camshaft, or the tuner.
Your poor mileage may be more a result of your camshaft,
but you might also want to try VS carb for a while to see if things improve.

 

D F, now we are talking my language.

How exactly does this work with leaving the stock ECM in the car and also using the commander950?

 

Well guys, I'm going to stick with the carb for now. I have better things to spend the 1400 bucks on.....like school, lol. If I had the money I would totally do it though. Thanks.

 

i'm thinking of buying the 950/stealthram setup. I'm just not sure it will do everything i need. I heard a rumor that an EGR capable emmissions legal version of the stealth ram might be produced, has anybody else herad of this??

 

well even if holley makes an EGR compatible Stealthram, the COmmander 950 / Stealthram setup will STILL not be emmisions compliant, simply because the commander cannot control emmisions equipment.

 

My car eeks by now with the q jet and a good cat. I know i won't be legal to the letter of the law but in NYC we need to pass a dyno test and a visual inspection. Most mechanics just look to see if the equipment is there they are not responsible for testing if it works or not just the dyno test. I figure i can pass it off as a TPI conversion and say its an 87 or later setup. so long as i pass the dyno i should be good. I would like EGR for the mileage enhancing ability and because it was there originally ( the visual part).

 

My car eeks by now with the q jet and a good cat. I know i won't be legal to the letter of the law but in NYC we need to pass a dyno test and a visual inspection. Most mechanics just look to see if the equipment is there they are not responsible for testing if it works or not just the dyno test. I figure i can pass it off as a TPI conversion and say its an 87 or later setup. so long as i pass the dyno i should be good. I would like EGR for the mileage enhancing ability and because it was there originally ( the visual part).

 

frankly ive gotten just as good if not better mpg without egr on my TPI. way back when my friend was burning chips he disabled it for fun and my mileage did not change noticably at all. im sure other people have similar results....

after all its supposed to "cool" the combustion during cruise, but ive always had better luck with a hotter more thermal efficient motor on the highway.

 

After thinking about the Commander vs GM ECM. I just don't think I have the time or the patience to sort thru all of it. I'm goin to sell my MiniRam, 58mm TB and Paxton supercharger and puta carb on. I know people will dissagree but I just don't have that kind of time.

 

I believe TPI is a little better than TBI but going from 19 to 27 MPG, I find it hard to believe it could make that much difference, why would it make so much difference if both are programmed to run the same air fuel ratio? I have a modified stock TBI and can pull down 25 MPG easy on the Hwy., and it's not tuned perfect either.

 

Well most people with TPI get 24-26 MPG with mild setups. I know I am.

Now my 100,000 Mile 89' RS 305 with TBI and the factory computer only nets me 17-18 MPG on a good day.

So thats what im comparing. my 355 with nice heads cam and intake, with TPI and the commander 950 getting 26-27 MPG,

compared to my totally stock 89 RS with 100K and 305 TBI getting 17-18 MPG Hwy.

so yes it did jump up quite a bit, although it was NOT a direct swap there was a whole new motor involved.

... And BTW air/fuel ratio tune has some to do with fuel economy, but not all. the TPI injectors operate at a much higher pressure and vaporize the fuel far easier than any TBI setup, so less fuel is needed to produce the same power / fuel economy. there is also less place for fuel to collect such as right below the throttle body, since fuel is sprayed directly onto the intake valve. you can also more precieselly meter the fuel since there are less variables involved, like how many turns are there before the intake valve and what effect that will have on atomazation and fuel droplet fall out such as when air goes around a sharp bend. things like that increase brake speicific fuel consumption (bad thing) and make the motor less efficient. having the proper A/F ratio is only half the battle.

 

When my 92RS 5-speed was totally stock I remember it getting at least 20-22MPG avg. and would pull down 28-31 MPG on the interstate on long trips, even after 100,000 miles it would do that, is your RS an auto?

 

yep and most people on the TBI board with auto 305 TBIs from pre 90's get about 18 MPH on average.

 

LOL, my car goes a little faster than 18mph! :P

 

shoot there must be somthing wrong with mine then

I guess its the fuel pump so let me go out and remove my entire rear end and exhaust so i can swap it out with a high pressure TPI pump that should wake it up.

 

And on a side note just because it pertains to this subject ill be installing another commander 950 TPI setup on my car tommarow.

Right now its in pieces and im painting up the intake plenum and runners, porting them, etc..

then it all goes in... and ill get a ton of video so if somone wants to host it or such i can send it.