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GM TBI + nitrous:

vandelay industries

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Could we discuss, in great detail, how GM TBI works with nitrous?
i'm just weighing my options, because i am, apparently, incapable of getting a q-jet to run. Here i am talking nitrous and i can't get my engine started........Clearly, i am delusional........

1) Let's discuss in very great detail; Let's pretend like i'm 5 years old, because mentally i am.


Wouldn't the computer be confused if more oxygen/fuel is injected into the airstream?
 

Bent77

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Yes. The best part of TBI is it’s super stupid. It’s simplicity is why it’s so reliable. The factory parameters are fairly tight on how much extra fuel can be added

So unless you want to venture into controlling it with a different PCM, probably not the best choice
 

vandelay industries

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Yes. The best part of TBI is it’s super stupid. It’s simplicity is why it’s so reliable. The factory parameters are fairly tight on how much extra fuel can be added

So unless you want to venture into controlling it with a different PCM, probably not the best choice

See, the thing is NOS offered a kit for it and Nitrous Xpress has a kit, both i ASSume with no chip mods required. So, i'm ASSuming it IS possible----just not clear to me how.

Basically, my backstory is---i want the simpliest /hassle free/ hitch free system to get the engine running. Because my ability, simply isn't there; See my other disaster threads in the garage section.
 

82355

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How does adding nitrous help you get the engine running?

Martin
 

tRustyK5

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Nitrous is usually the fastest way to stop an engine from ever running again. :haha:

Nitrous is injected with extra fuel when activated, usually at full throttle. In the most basic terms Nitrous brings oxygen to the party, which allows you to add more fuel and make more power. More nitrous, means more fuel means more power. You could probably get away with a 50 hp shot on a TBI engine.

None of this pertains to getting a engine running though. Nitrous is just a "power adder" most often used for drag racing applications.
 

bp71k5

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I could see how you might get nitrous to work with TBI, as the TBI has a MAP table (Or at least an enrichment parameter) to use when it goes wide open throttle so I’d assume you could set it to dump fuel into the intake when the pedal is down and then activate a switch to inject the nitrous at the same time? It’s been a bit since I tuned mine though.
 

1-ton

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Spend $500 on a complete nitruos kit, spend many many hours installing it, then inject that into a TBI swirl port head, and get a tiny kick of power out of it. Sounds about right. Go for it! :D
 

dyeager535

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From what little I just read, nitrous nor forced induction would be worth a damn with the stock TBI heads.

I think a turbo or supercharger setup would be cool in general, but there is a lot that goes into any of those setups, making the cost/benefit questionable unless you absolutely know that you can use the power they make.
 
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Blue85

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Why worthless? A 50-shot is like 35% more power on a stock TBI. It should work just like spraying under a carb. Set the switch so you know it's WOT and the ECU will be open loop anyway. Probably not a bad idea to put an RPM gate on it, too. Have to make SURE the fuel pump can deliver, so might need upgrading and an additional regulator might be required since TBI runs at a less common pressure.
 

ZooMad75

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Lost me at "can't get my engine running right, let's try to put it on N2O".

A poorly running engine with the spray is going to be a disaster of the catastrophic variety. Be sure to take video and pics when it lets go. We like carnage.

Still, even with a wet plate system I'd say you also have to add some form of timing control to back it off during the spray. So by the time you spend the money on the kit, aux fuel delivery and timing control you could have been most of the way to a more modern injection system that could be putting out more power all the time with the added bonus of better driveability.

But hey, I'm crazy that way. I'm too cheap to spend money with the high probability of me blowing the engine up on the giggle spray.
 

vandelay industries

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Let me clarify the situation here:

1) i thought, since i couldn't get the engine running/running right with carb that switching to GM TBI would remedy that. Likely so, and things have changed a bit since i started this thread. Moron this in my other threads.

2) Since, my goal for the engine was/is about 250hp, then the reason why i was asking about nitrous and TBI was for furthering the reasons for or against to switch to TBI in the first place----since i was on the fence whether to stick it out with the carb or take the easy way out and go fuel injection. This was not to suggest nitrous would help the engine run "better." i mean, please....i'm not THAT stupid.

TBI and nitrous straightforward-----more of a reason to switch to TBI

TBI and nitrous difficult-----more of a reason to stay with carbs.
 

dyeager535

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Why worthless? A 50-shot is like 35% more power on a stock TBI.

I saw a lot of articles that talk about displacement and exhaust flow. Here is a very brief one, but there are many more: https://www.google.com/amp/s/perfor...take-and-exhaust-flow-with-nitrous-oxide/amp/

Just seems without considering heads, cam, and exhaust changes (ignoring however youd need to tune TBI to play nice) increases of x y or z with nitrous aren't a given.

It's seemingly a fair bit more complex than just hooking up a bottle and opening it up when you want to make power. Maybe you can do so without any engine changes, or the difference without doing so isn't a big deal, and the references Ive seen are for all out performance.
 

ZooMad75

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Let me clarify the situation here:

1) i thought, since i couldn't get the engine running/running right with carb that switching to GM TBI would remedy that. Likely so, and things have changed a bit since i started this thread. Moron this in my other threads.

2) Since, my goal for the engine was/is about 250hp, then the reason why i was asking about nitrous and TBI was for furthering the reasons for or against to switch to TBI in the first place----since i was on the fence whether to stick it out with the carb or take the easy way out and go fuel injection. This was not to suggest nitrous would help the engine run "better." i mean, please....i'm not THAT stupid.

TBI and nitrous straightforward-----more of a reason to switch to TBI

TBI and nitrous difficult-----more of a reason to stay with carbs.
I guess I was being a bit sarcastic. No offense intended.

I understand the goal wasn't to make it run better by adding the n2o but to reach the HP goal. But still, that being said, running n2o with TBI or a carb still won't always be running at 250hp, but say 200hp until you hit the button. For all the costs involved with the n2o kit and associated goodies needed it seems like you could spend that money better to get the target of 250hp all the time vs only having it some of the time until the bottle runs out.

Cam/lifters, intake, carb, and some minor exhaust could do a lot to get you at or near the 250hp mark for the same money or less than all the nitrous stuff.
 

vandelay industries

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A stock goodwrench 350 crate could probably make 260-290hp straight out of the box without even trying. But i feel i want to stick with this engine instead of buying another one, although the crate 350 route would be the easiest.

Yes, i realize a cam change, especially, and maybe some head porting (i don't have the vortec heads, i have the "crappy" pre-vortec heads...) can probably get me to 250hp, but i feel nitrous would be simpler. The stock 4.3 non vortec heads makes about 140-160hp/around 230 lbs tq.

It's going in a chevette or monza, so i don't need bigtime HP to go fast.

P.S. This 4.3 is really my "first engine." GM reman crate.
 
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dyeager535

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So the goal is to run a TBI 4.3 in a small car? Dunno about 250hp+, but I would surely think better heads, cam swap, and good exhaust would make significantly more power than what it did stock.

I don't know as I'd consider a power-adder like nitrous as easier, especially since it's a finite quantity. Being all motor is significantly "simpler" as there is less to go wrong, assuming goals can be reached without getting into ridiculously expensive parts. Within reason of course, running the ragged edge of destruction will eventually lead to that.

The typhoon/syclone setups would probably be a lot of fun, if they could be cloned on the cheap. But I expect not.
 
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