Well on the 1994 L03 anyway. I am driving it so many miles towing trailers in 3rd gear at 2,800-3,200 RPM, I might as well have an intake that works very efficiently there. Should help give that little 305 some extra mid-range grunt. I am rarely under 2,500 RPM or above 4,000 when towing, so it should be a good choice.

Just need to talk to Haulin more in depth about the 8192 TBI PCM to run TPI conversion.

 

Fast,

Hey man I have a question for you. I am trying to decide whether or not to stay with TBI. I really would like to supercharge or turbo my car someday and was wondering what you think would be a fuel setup for it TBI or TPI?

Thanks

BIll

 

Hope you don't mind me stepping in...
If you plan to turbo or supercharge your car, the shape of the intake is not a huge concern, but the fuel delivery will be. With a stock TBI you will not be able to deliver enough fuel to support big horsepower even with the 80pph injectors and lots of fuel pressure. On the contrary, there WERE some bolt on supercharger kits for TBI's, though. you just can't run much boost. I would predict tbi is limited to around 350 hp max for fuel delivery reasons. once again, on the contrary, there are 4bbl tbi's that can handle 500+hp.

I switched from TBI to TPI because it wasn't too hard and it has been done countless times before, it is easier to get fuel injectors and there has been a ton of research and tuning discussion. not to mention I think it looks cooler.

 

Might want to up your TBI hp predictions to 400-450 for a 2-barrel unit, and the sky is the limit on a 4-barrel unit. Although wet flow isn't the best idea for any kind of forced induction.

Fast, You HAVE to do a direct comparison of TBI to TPI. You have access to a dyno, and your very thorough in your street testing. The TPI guys won't believe you no matter how the results come out, but I'm very interested in how the long runners effect your low RPM VE's. Any chance you can get us before and after dyno charts????? It would be very interesting to see the difference under controled conditions like just swapping inductions and retuning the fuel side of things.

 

Ttype Camaro,

How does the turbo's run for you? Just wondering.

Bill

 

The turbos run great. My car is the fastest car I've ever been in besides a NASCAR. Its all in the tune though. I've spent days tuning and data-logging with a wideband O2 sensor and the Holley Commander 950 PRO. Never had it to the dyno, and I've never made it down the track without something going wrong (transmission/wastegate/boost controller failures). Best time (with the chrysler turbos) was 13.24@109mph when the 700r4 wouldn't shift to 3rd untill I let off for a second or two, then ran out of gear in 3rd and topped out at 109. I towed a Dodge Caravan with my Camaro and barely even noticed it back there. The Holley Commander 950 software has a horsepower calculator according to the amount of fuel being injected and it estimates 515hp and 475ftlb of torque at the flywheel, which seems a little high, but I realy don't know. Fuel economy isn't amazing but its pretty good for the amount of power, 14-15mpg city and 20mpg highway.

 

so, lemme get this right.

one of the most experienced and informed tbi 305 guys on this forum is gonna have a tbi 355 and a tpi 305?

makes sense, heh.

 

How do you like that commander 950? I was thinking of going to an aftermarket ecu also. I heard that they pretty user friendly too.

Bill

 

The Commander 950 is ok at first, but gets much better as you learn. The only two things I wish it had were an auto-learn function and data-logging for acceleration enrichment. Sofakingdom wrote an auto-learn program for the older 950 software, but not the PRO (which is what all the new kits use). If I could do it agian, knowing what I know now, I would have gone to the TBI EBL (adapted for mpfi) or did the extra work/learning for the megasquirt system. Now that I have the HC950, its hard to get motivated for change because it runs great and its so easy. If you don't mind spending the money, go with the accel gen 7 dfi. Also, wideband O2 tuning is necessary to get it right when modified extensively.

 

Will I need to have a tpi wiring harness also or does the ecu come with its own wiring harness?

 

The Holley PN:950-101 comes with a wiring harness for a TPI engine.

From experience, leave your stock TBI wiring harness in-tack, incase you want to upgrade to the EBL when you get better at tuning or bored with the 950. I had a TBI harness and removed all the extra wires for a cleaner look, but it ended up looking worse in the end and then the whole harness was ruined because it was missing wires.

edit: I've also heard of a guy who re-pinned the harness to except the HC950 ecu so he didn't have to buy the harness too. I would try that if I could go back in time. While the harness in the kit is not a perfect fit, it might still be the easiest route, just not the best looking. The HC950 harness is a little short so I've heard of drilling through the firewall by the transmission instead of right above the stock ecu plug inside the passenger fender.

 

Thanks for the info man. I am going to look into buying a setup like that. So is it pretty easy to tune? I have never even did any datalogging, but have built and worked on my cars. My experience is in the stock tbi setup that I have and carbs.

 

Just read the manual that comes with it over and over! I strongly wouldn't recommend tuning without a wideband kit. Since the Holley WBO2 is like $800, or something crazy like that, just get the innovate motorsports LC-1 with the XD-1 guage kit for $400. The XD-1 is much more useful than you'd think when tuning.

Also, there is a ford 5.0 specific tuning section that really helped me tune idle in my 355 TPI. Specifically the PID control in the advanced user mode. D=5, P=4, I=3 for my engine. Default values are like 128, 64, and 32, which make it idle crazy then stall in park or neutral, but keep it alive when you put it in drive, so be sure to hook up the park neutral stepper if you have an automatic.

 

That's what I'm screaming!!!!! This is the same guy who convinced me to keep my TBI setup instead of going with TPI on my 383.

 

The TPI swap still had the L03 longblock minus the peanut cam in it (LT1 cam).

Here is the link to that whole project.

https://www.thirdgen.org/forums/tbi/...ml#post2976055

The TBI 350 was installed, because the GM crate 350 TBI actually cost less than the 305 version did. Basically got tired of not being able to find a Decent machine shop. The Crate 350 TBI actually makes considerably less power than the 305 that it replaced.

The 305 TBI still exist, it just has such a high powerband, that it is not very suitable to pulling around 5,000 lbs and a trailer.

 

Thanks for the advice brother. I will pm you sometime and let you know how I am doing. Thanks again.

Bill