Guest traub83 Posted October 24, 2005 Share Posted October 24, 2005 I am seriously thinkin about buyin a tbi system from holley for my sbc powered z with the 144 supercharger. I have a 750 holley on it now but I am thinkin on goin with the holley comander 950 tbi system for the 600hp setup, what all could i expect to gain by switching to this system over my carb?? Im lookin for a lil better gas mileage so how much if any should I expect?? also a lil power would be nice and easier starting even tho its not hard now just warm up will be easier with tbi i think and i can use my laptop to tune my fuel settings... What do you guys think on this?? Quote Link to comment Share on other sites More sharing options...
getZ Posted October 24, 2005 Share Posted October 24, 2005 I'm not so sure that setup will work without remapping the entire fuel curve. I think that system was programmed for normally aspirated cars. I thought that Holley did have online fuel maps though. As far as power, I don't think you will see any peak horsepower gains over a well tuned carburetor. It does make cold startups nice. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted October 24, 2005 Share Posted October 24, 2005 I don't think a TBI is gonna be able to support that blower with the fuel you need over the range. Talk with Holley's techs and explain your setup to them... Mike Quote Link to comment Share on other sites More sharing options...
skipzoomie Posted October 24, 2005 Share Posted October 24, 2005 Correct me if I'm wrong, but I don't think you can use 600HP and fuel savings in the same sentence. It takes a lot of oats to feed that many horses. I agree with Mike. Talk to the guys at Holley. They're a bunch of good guys. They sent my brother a new ECU for his Projection when it went bad prematurely. Can't beat that for service. Quote Link to comment Share on other sites More sharing options...
Guest traub83 Posted October 26, 2005 Share Posted October 26, 2005 Well I dont expect to get 30 mpg out of it lol... I am just thinking even 2mpg increase will be worth it to me, and I will be able to use a laptop to fine tune my fuel system and get to monitor it with precision unlike with the carb... My carb is tuned quite well tho but I plan on traveling a lot next season and takin it to a bunch of different tracks and I dont want to have to retune my whole carb each time when I could just plug in a laptop and read my gauges Seems like it would be a better combo and a lot cleaner look and more hitech when I hit the track!! Quote Link to comment Share on other sites More sharing options...
skipzoomie Posted October 26, 2005 Share Posted October 26, 2005 You could be pioneering a new field. I can't recall reading anything on using TBI on hi-performance engines. There are different size TB's. Maybe even use multibles. It's a very interesting concept. Try it and let us know how it works. Quote Link to comment Share on other sites More sharing options...
Guest traub83 Posted October 26, 2005 Share Posted October 26, 2005 Im going to get ahold of holley today or tomarrow and see what they have to say but if they say yes it iwll work then Im going for it, Cause I know on there site they have tbi systems for like 800hp setups so if that isnt hi performance i donno what is lol... but maybe forced induction will be a lil different?~! Quote Link to comment Share on other sites More sharing options...
mobythevan Posted October 26, 2005 Share Posted October 26, 2005 If you like the DIY stuff and want to control fuel and spark completely then you could go the route I am with my BBC and 250 charger. Use this throttle body for TBI and megasquirt for control. I think you can pick up considerable mileage at cruise with MS controlled TBI setup versus carb. This throttle body bolts to holley pattern and I had mine bored out for 1000cfm flow. Just another option, I'm not saying it is the best. Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 27, 2005 Share Posted October 27, 2005 Think of a TBI as a carb you have more control over (with the right ECU and tuning). Although wizards can tune a carb to do a decent job at many load conditions, it's easier to cover all the bases with EFI, whether it's TBI or port. I think the TBI on a blown engine will work well, and might even be better than port injection. Having the fuel in the blower can provide some cooling of the mixture. Quote Link to comment Share on other sites More sharing options...
Guest traub83 Posted October 27, 2005 Share Posted October 27, 2005 thats what I was thinking with the tbi setup like a carb just ran by a computer, I am going to run a fuel cooler also before the TBI unit to aid in cooling inside the blower!! I should gain some power by using this if not only a few hp but im actually thinking I will gain prob around 20 horses doing this as well as having full control over my fuel maps! Quote Link to comment Share on other sites More sharing options...
BrandonsZ Posted October 27, 2005 Share Posted October 27, 2005 They have manifolds that will accept multi-port injection now (just before the valves, that would be preferred over TBI, TBI is a glorified Carburator which happenes to be controlled metering through electronics IMO. You can get better efficiency though a TBI instead of a carb because carbs (if not set up right) can be sloppy. A properly tuned carb shouldn't have any trouble starting the car cold if you have a choke. It's easy to think a carb is setup right and live with a marginal setup because it works, you could probably squeeze 2 mpg with a proper dyno tune on your carb, unless you happen to have the perfect jets in there already (not likely). Quote Link to comment Share on other sites More sharing options...
Psykovertible Posted October 30, 2005 Share Posted October 30, 2005 well the port injection would rock even more than a TBI simply because it's more efficient. however, he has the 144 blower that likely doesnt mate to a TPI intake. i've never had one i'm just guessing. Arizona Speed and Marine and Arizona TPI are two well known places here that do very nice work. I like the holley 950 TBI systems but would buy a stealth ram if i had the money. Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 30, 2005 Share Posted October 30, 2005 well the port injection would rock even more than a TBI simply because it's more efficient. however' date=' he has the 144 blower that likely doesnt mate to a TPI intake. i've never had one i'm just guessing. Arizona Speed and Marine and Arizona TPI are two well known places here that do very nice work. I like the holley 950 TBI systems but would buy a stealth ram if i had the money.[/quote'] Not sure what you mean by "rock" but the only thing you get from port injection is intensely tuned cylinder to cylnder mixtures, and that matters mostly at idle and part throttle. Once a high performance engine starts to work at higher rpms and WOT, mixture distribution is a minor issue for power production. Most of the fuel will be liquid sitting behind the valve, then turn to vapor once the overlap exhaust hits it. Fuel only burns as a vapor, and even if you injected straight into the combustion chamber, the best an injector does is squirt atomized fuel, not vapor. I still think that TBI will be a benefit on a 144 blown engine anyway, since the fuel in the mixture will help cut down the mixture temp after compression by the blower. The down side is that the extra volume taken by the fuel in the fuel/air mix will mean less compressor efficiency. These may offset each other. Just because port EFI is newer and used by the OEs doesn't mean it's better for power production, or overall efficiency at WOT. It's there for cold start and idle mixture distribution issues that are directly linked to emissions. Newer technology isn't always better. Just my opinion. Quote Link to comment Share on other sites More sharing options...
Guest traub83 Posted October 31, 2005 Share Posted October 31, 2005 yes im really thinking about the tbi seriously now!! I contacted holley and they say it will work great on a supercharger system!! they couldnt tell me mileage guesses or power increase but they say I should notice an increase in both area's just dont look for 100 extra horse Quote Link to comment Share on other sites More sharing options...
Psykovertible Posted October 31, 2005 Share Posted October 31, 2005 well one of the things i was told in the beging when trying to learn about this stuff was that dry air in an intake can reach higher velocity. in addition, the turbulance needed to maintain the atomization and fuel suspension is unneccessary for port injection. technically (according to at least on dude i spoke with) you could mirror polish the inside of a port-jection intake to obtain smoothest flow and highest velocity of the "dry" air charge since the fuel does not need to be suspended througout the plenum and the runners. never thought about the the fuel vapor vs liquid form. hell-of-an oversight on my part that now makes me think...... what an a**.... cant believe that never occurred to me. how many beer drinking chats did the cigarette into the cool bucket of fuel have i had? Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 31, 2005 Share Posted October 31, 2005 Michael is our resident aerodynamics PhD, so hopefully he'll chime in and correct me, but I believe the boundary layer (area where flow goes from zero to some significant percentage) is about 1/8". Minor surface finish details (rough sand casting surface versus polishing) won't amount to an appreciable effect, since the roughness of the sand cast doesn't reach into the boundary layer far enough. In a sense, your source is correct about the issues of fuel drop out. It happens A LOT in a street application, but it ends up not mattering much as far as mixture quality in the chamber, since the thermodynamics and aerodynamics there put the fuel (whether atomized or puddled on the intake or port) into a vapor form. It does end up mattering somewhat due to the proportions of fuel that are in the mix in each cylinder, as far as the final air/fuel ratio that results from the vaporized fuel content in each cylinder. A lot of fuel drop out can mean that some cylinders may be lean (not getting enough dropped out fuel trickling down the port) or too rich (too much fuel trickling down the port). The magazines always talk about fuel atomization, and lead you to believe that better atomization from the injectors or in the ports is some sort of holy grail. Unless it's David Vizard writing the article, I sit there with a HUGE salt shaker! As long as you can be sure there's no fuel vapor above the gasoline in the bucket, and there's no flame or spark, you could probably put a cig out in the cool gasoline - but I certainly wouldn't condone that experiment! Quote Link to comment Share on other sites More sharing options...
Psykovertible Posted October 31, 2005 Share Posted October 31, 2005 not just no but f-no on the bucket of gas. safe or not I'm not gonna play the role of Beaker for nobody Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 31, 2005 Share Posted October 31, 2005 Good choice! We need good HybridZ people - that don't have all of their skin burned off!!! Quote Link to comment Share on other sites More sharing options...
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