454 tbi go to carb or keep tbi??

[alberta91crew]

HELLO
I have a sqaure body 91 Crew with a 454 TBI, it runs and starts good but i am looking to get a little more out of it, should I do a swap to carb or should i stay with the TBI?
If I stay what can I do to make it work good? headers? intake? what kind?
Thanks
New to TBI so any good info would be appreciated

[bloertcher]

TBI is reliable as the day is long,but if you want much more performance than stock,it falls way short.If your looking for a small improvement in power,a good set of headers and exhaust,and an intake,along with an open element air cleaner will help.Not sure who all makes a 454 TBI intake,pretty sure edelbrock offers a performer for it.
If you want a dramatic improvement,go carb.All but the mildest of cam upgrades give the TBI fits without major prom work.

[Bob B.]

Look at it this way: TBI is very reliable, and will give you about the best fuel economy you can ever hope to get out of a '91 454 Crew Cab. bloertcher is right about mods., a manifold, headers, and an open air cleaner is about all you would want to do with it. Maybe you could find a Hypertech chip for the ECM.

[mountie]

Back in the mid '90's, I noticed my TBI ... the shaft for the butterflys was loose in the housing. I went to a local place that had their version of a performance TBI replacement. Well, the new TBI "looked" better ( anodized stuff).... But I didn't find much of a difference with it. But I did get a raised gasket (3/4" thick) below the TBI, and made a vortex-like intake, mounted with rivits on the bottom of the air cleaner ( about 4" tall), ...all this to create a sort of "high-rise", to improve air flow. I have a Tornado in the air cleaner that improves up-hill driving.

But.... I did have a Quadrajet Carb blueprinted by a Pro-Stock Drag racing carb builder.....(for a Chevy box van I hauled a race boat) It was like I installed a dual-turbo on the truck I drove!!

[alberta91crew]

What do these 454ss guys do? or was that a different engine?
if i wanted to swap back to carb what would need to be done?

[mountie]

Originally Posted by alberta91crew

What do these 454ss guys do? or was that a different engine?
if i wanted to swap back to carb what would need to be done?

Consider the cost verses the gain. Headers is a minimal gain for the result (cost-wise).....

A TBI is fine..... Or, do you want a 4-barrel set-up? Call Edelbrock for advice.

Maybe just a chip?

I was told, a long time ago, from a successful NHRA drag racer, that the best set-up is a properly running stock configuration.

I had a '70 GTO. It was stock ( with a performance auto transmission). It won at the drags at night, over modified cars that ran with glitches. ( Too many mods)

Keep it simple!!! Keep the stock parts good and adjusted.

[AnniesSS]

Originally Posted by alberta91crew

What do these 454ss guys do? or was that a different engine?
if i wanted to swap back to carb what would need to be done?

After we rebuilt my motor, the TBI couldn't keep up, so we went to a stock Holley carb. It helped a lot, but when I upgraded to a Quick Fule Tech custom built, it made a world of difference!

As for MPG, I only got 14 mpg on the highway and with a worked 496, I get about 8-9 around town and I have yet to take a real long roadtrip. We're going to Carlisle All Truck Nats in a few weeks, so we'll see how the mpg is.

[mountie]

Originally Posted by AnniesSS

After we rebuilt my motor, the TBI couldn't keep up, so we went to a stock Holley carb. It helped a lot, but when I upgraded to a Quick Fule Tech custom built, it made a world of difference!

As for MPG, I only got 14 mpg on the highway and with a worked 496, I get about 8-9 around town and I have yet to take a real long roadtrip. We're going to Carlisle All Truck Nats in a few weeks, so we'll see how the mpg is.

A blueprinted carb makes all the difference. I had a Quadrajet built by a Missouri shop that did NHRA ProStock cars. Major difference.

Anyone know of a good TBI builder?

[ProStreet68SB]

Originally Posted by alberta91crew

What do these 454ss guys do? or was that a different engine?
if i wanted to swap back to carb what would need to be done?

same motor/transmission. Theres a whole forum of advice for TBI big block over at 454ss.com Theres also some guys over ther flowing 800+ cfm on a 2bbl tbi setup

iirc to switch to a carb on these, require a qjet and a new dizzy. As I think the manifolds came with an adapter from the factory, from qjet to tbi.

[BigBlocksRule]

Originally Posted by mountie

I have a Tornado in the air cleaner that improves up-hill driving.

Please tell me you're kidding...

[mountie]

Originally Posted by BigBlocksRule

Please tell me you're kidding...

Let me go outside... take some pictures..... I'll get back to you.....

(10 minutes later.....)

Here are pictures......

I learned about the Tornado from the Mears Gang. I worked for Team Mears, in Bakersfield, Ca. I had to drive over the mountains, between Los Angeles, and over to Bakersfield. The grade is steep & long. Mears use the Tornado in their Motorhome, their pick-up trucks, etc, to improve up hill driving at less RPM's. I actually learned to use less "peddle" up the hill after getting my Tornado.

Before I got the Tornado, I had a bluprinted TBI, and had a vortex aircleaner base made. I use a heat reflective material under the underside to lower the engine-caused heat into the cleaner.

( I drove their semi-transport for their INDY season)....

[mountie]

The Tornado is a vortex generator that swirls the air, at a higher speed at the air/fuel mixture. making the atomization more efficient.

I noticed the up-hill drive immediately! I gained 6 mph at less peddle.

[toothenator]

Originally Posted by mountie

The Tornado is a vortex generator that swirls the air, at a higher speed at the air/fuel mixture. making the atomization more efficient.

I noticed the up-hill drive immediately! I gained 6 mph at less peddle.

So you increase the overall drag coefficient of the intake manifold for greater bottom end combustion efficiency?

[BigBlocksRule]

I'm curious as to how the swirl this thing generates makes it through a pair of throttle plates and past a couple of big honkin' injectors.
I've seen several of these tested a few years back and none were proven to help with anything other than the bank accounts of those who sell 'em.

[mountie]

Originally Posted by BigBlocksRule

I'm curious as to how the swirl this thing generates makes it through a pair of throttle plates and past a couple of big honkin' injectors.
I've seen several of these tested a few years back and none were proven to help with anything other than the bank accounts of those who sell 'em.

The swirling of the air, improved the mixture..before the butterflies...

The Mears gang, in Bakersfield, had one in their motorhome and gained performance up the steep grade over the Grapevine from Bakersfield to L.A.

They then, got them for some of their other vehicles.

[toothenator]

Originally Posted by mountie

The swirling of the air, improved the mixture..before the butterflies...

The Mears gang, in Bakersfield, had one in their motorhome and gained performance up the steep grade over the Grapevine from Bakersfield to L.A.

They then, got them for some of their other vehicles.

Any idea how much drag is created vs power output from this contraption. I would assume the losses out weigh the gains. I would also assume it kills the top end

[mountie]

Originally Posted by toothenator

Any idea how much drag is created vs power output from this contraption. I would assume the losses out weigh the gains. I would also assume it kills the top end

All's I know, when I went up a steep incline, I learned to slightly back off the throttle to keep the same speed I used to go, with out it.

(In a NHRA 10,000 HP nitro engine, ..the blower requires 400 HP, just to turn the blower.. 100 times the positive, verses the negative.)

There's pressure in the air filter housing...... no drag there.

Hey, if you don't go up hills, ( Texas?).... you may not notice the difference.

[toothenator]

Originally Posted by mountie

All's I know, when I went up a steep incline, I learned to slightly back off the throttle to keep the same speed I used to go, with out it.

(In a NHRA 10,000 HP nitro engine, ..the blower requires 400 HP, just to turn the blower.. 100 times the positive, verses the negative.)

There's pressure in the air filter housing...... no drag there.

Hey, if you don't go up hills, ( Texas?).... you may not notice the difference.

Powering a compressor (blower) lowers the amount of work required to fill the cylinder in addition to increasing the volume of air. Inducing turbulence outside the engine (tornado) only creates more drag for the incoming air

[mountie]

Originally Posted by toothenator

Powering a compressor (blower) lowers the amount of work required to fill the cylinder in addition to increasing the volume of air. Inducing turbulence outside the engine (tornado) only creates more drag for the incoming air

I don't think a stock small block - TBI, w/ smog, cares much about a little swirling air.

Heck, headers may sound / look cool, but $400 cost gets you $10 of performance on a stock engine.

[toothenator]

Originally Posted by mountie

I don't think a stock small block - TBI, w/ smog, cares much about a little swirling air.

Heck, headers may sound / look cool, but $400 cost gets you $10 of performance on a stock engine.

You don't care because you don't understand the principles of fluid dynamics and yes, easing the exhaust flow of a choked motor won't do much but restricting air flow on the intake side will do the opposite

[mountie]

Originally Posted by toothenator

You don't care because you don't understand the principles of fluid dynamics and yes, easing the exhaust flow of a choked motor won't do much but restricting air flow on the intake side will do the opposite

The Tornado does not restrict air flow.....

I shouldn't have to explain my resume, but my info comes from 3 NHRA Funny Car tuners, inventor of Turbine Off-Shore powerboats ( 200+ MPH), & a 16 -time Bonneville Salt Flats speed record holder to name a few.

It's all about common sense, and what's worth engineering for performance, and what the end results produce.

[toothenator]

Originally Posted by mountie

The Tornado does not restrict air flow.....

I shouldn't have to explain my resume, but my info comes from 3 NHRA Funny Car tuners, inventor of Turbine Off-Shore powerboats ( 200+ MPH), & a 16 -time Bonneville Salt Flats speed record holder to name a few.

It's all about common sense, and what's worth engineering for performance, and what the end results produce.

It is impossible to alter the air flow without taking some of your working energy, the engine's vacuum, and converting it into the "swirl" of the intake air. Thus, air is restricted.

You never get out what you put into any system. The only issue with this contraption is that the supposed increase in combustion efficiency makes up for the drag force created outside the throttle body. To say this tornado doesn't restrict air flow is to say it works without requiring any energy.

I am skeptical. Show me dyna results. Don't just tell me that a race team uses it. That means nothing to me

[toothenator]

http://www.popularmechanics.com/cars...ileage/1802932

Read the part about the tornado. Took me a little while to find a reputable website talking about this product. It was mostly forums making fun of the people who buy this crap

[LynnJr]

If it was my truck I would go with a new manifold and Carb.You will be able to feel the difference and it won't cost as much as changing the TBI.

If you upgrade the TBI you need the new chip as well and the air filter will make it sound good but it won't give you much power.The headers will keep your floor hot but again not much of an improvement.

[mountie]

Originally Posted by LynnJr

If it was my truck I would go with a new manifold and Carb.You will be able to feel the difference and it won't cost as much as changing the TBI.

If you upgrade the TBI you need the new chip as well and the air filter will make it sound good but it won't give you much power.The headers will keep your floor hot but again not much of an improvement.

I had a quadrajet blueprinted by a ProStock carb guy ( Fenton Mo)..

It was like adding a turbo......