TBI vs vortec (1 Viewer)

[tclark]

Yeah I didn't think about the spark, even though I knew it didn't have a distributor. I know the efi system is better, but also requires more sensors and such; I was thinking you could get the improved block/head design and keep the efi as simple as possible.

 

[lehiguy]

Yeah I didn't think about the spark, even though I knew it didn't have a distributor. I know the efi system is better, but also requires more sensors and such; I was thinking you could get the improved block/head design and keep the efi as simple as possible.

TBI chips did my chip burning. Excellent stuff, although I'm still partial to carbs. LS motors can run carbs or possibly even TBI with the help of this stuff; http://www.jegs.com/p/MSD-Ignition/...-GM-EFI-Carbureted-LS-Engines/758329/10002/-1 GMPP now offers a mechanical distributor drive for LS engines that utilizes a Ford distributor driven off the front of the cam. You can google that.

 

[norsk]

TBI chips did my chip burning. Excellent stuff, although I'm still partial to carbs. LS motors can run carbs or possibly even TBI with the help of this stuff; http://www.jegs.com/p/MSD-Ignition/...-GM-EFI-Carbureted-LS-Engines/758329/10002/-1

Good to know

dougbert

 

[tclark]

Cool!

 

[Elbert]

Unless you get the 6.0 long block for free...It would be crazy in my view to install TBI on that. becuase you are planting a low power fuel system on a long block assembly that has the potential for good power.

All the talk about high horse power and different cylinder heads etc...are really in tune with hot-rod setups. You will not be using that off-road. Off-road you need to look at what makes torque/power in the low rpm range of the engine...say...1 to 3K. Thats where you can apply the power off-road. High flow heads and power made in the upper rpm range is not very useful to off-road driving (in the context of a FJ60). The so called vortec cylinder heads are an improvement over the stock emissions style 5.7 heads common on the TBI. Not that is bad to improve power etc....but think about how you can or will you be able to apply this power.

I can tell you that a 5.7 vortec will push the 60 beyond its handling characteristics on pavement real quickly....

TBI is great for a stock 5.7. Sure you can change many things... You'll have plenty of fun with a stock TBI 5.7.

If I were to run a carb engine on an old school platform (based on 5.7) a good off-road package is a 383 setup. If I wanted to max stock power for a truck based 5.7 with fuel injection I would run a 5.7 vortec. If I wanted a nice cheap dependable 5.7 stock setup with fuel injection the TBI is the choice.

Think about how you drive offroad.... hours on end in low range moving slow (depending on where you go) Gears and transmission make the truck. The stock aspect means ...easy to maintain, dependable, and serviceable...etc the farther you step away from stock the more issues you have to deal with and you better be good at DIY. A good clean idle, the ability to idle for a long time or moderate rpms without overheat, reasonable / useable power....all point to a TBI as a good choice.

You can add power many different ways...but does that increase the utility or can it be applied.

What I'm getting at is the fact that a stock TBI setup will most likely serve you well. If you want to go through the challenge and fun o modifying a engine for more power etc...then think about modifications that will increase torque and low end power and that do not impact dependability or driveability. When it comes down to figuring out issues...stock is the way to go..espically if you are not well versed in DIY service.

Many modifications are not worth doing unless you take a "team" approach. You can't simply just bolt on vortec heads to a 5.7 TBI and call it a day....you have to change the intake manifold, you may have issues with the emissions & exhaust...etc, you may have issues with emission in general in regard to passign that if you need to .

Nothing wrong with modifying your engine/truck, but I just wanted to draw a distinction between a hot-rod type setup and a off-road type setup. No matter how you approach modifications on the engine of your choice...you should consider what I call a team approach...in that the cylinder heads work with the intake and camshaft and fuel system...all of which are oriented as to the rpm range and desired power/toque output of the engine assembly. At the end of the day you'll have far more enjoyable trips with stock setup that requires no special adjustments to run all day in any environment and that you potentially could buy a GM service manual and be set for maintenance issues.

 

[ntsqd]

snippage
...I think it would be possible. It wouldn't really make anything any better over the vortec system.

This.

Elbert has my take on it too. The further from stock the less reliable.

The iron Vortec heads flow terribly, but they're fairly efficient for what they are. The problem with aftermarket cyl heads is that they're designed, as Elbert pointed out, for power in an RPM range that isn't really useful for most off roading. If you want a better head for a 5.7 (TBI or Carb'd) take a good look at the cyl head used on the 5.7 TPI Corvettes. The same casting number is what it used on the ZZ4 crate motors. It has a small intake runner (163cc or 165cc depending on what source you want to believe) and a small (53cc or something close), late model type combustion chamber. Compare those numbers to anything aftermarket.
So it will keep the intake velocity high at the rpms where you'll use the engine, and it will make for a decent comp ratio with a flat top piston. And being aluminum it will cool better, be less likely to detonate, and is repairable should something catastrophic happen to the engine.

A set of these heads on a ~9:1 SCR 383 would be an awesome engine for off road no matter what fuel and spark system it has.

 

[norsk]

Well, I have found (via articles - not real experience - yet) that the Vortec flows very well.

Article comparison: http://www.customclassictrucks.com/techarticles/0405cct_vortec_cylinder_heads_small_block_chevy/

The L-98 head is discussed at http://www.chevyhiperformance.com/techarticles/46359_gm_350_crate_engine_build_iii/ - a good head forsure

http://corvette.wikia.com/wiki/Head_and_Cam_Comparison


http://www.onedirt.com/tech-stories/engine/a-guide-to-vortec-vs-oe-small-block-chevy-heads/

is a good summary article from 2010, and there are other articles discussing this.

*Bowtie Vortec Heads with 2.02” Intake, 1.60” Exhaust Valves, 185cc Intake Port.
**062 Vortec Heads with 1.94” Intake, 1.60” Exhaust Valves, 165cc Intake Port.
***492 Straight Plug heads with 2.02 Intake, 1.60 Exhaust Valves, 159cc Intake Port.
Flow numbers are reprinted from Brzezinski Racing Products, Inc. All of Brzezinski’s flow testing above was performed at 28” of water with a SuperFlow 600 flow bench and Flow Pro software from Audi Technology.



This table compares Gen I heads, the L31 Vortec (from 1996) and GMPP Vortec (which I call Vortec II).
TBI Intake flows 185-190 CFM Way lower than Vortec or Gen I heads


The GMPP Bowtie Vortec actually has two heads: small runners (180cc) and large runners (206cc).
The small for low end power and the large for high end.

Just wanted to say that Vortec do have better numbers, but whether one uses that is left up to the reader. The smaller Bowtie is the one I am putting on my rig. I also remember you pointed out that L-98 Vett head in my thread.

I agree that the more stock a system, the more likely the entire system will work as promised.

dougbert

 

[preacherman]

I am Really thinking heavy about using the TBI set up. Sure it does not have the same hp as a vortec but it still has almost 75 more hp than the stock 3fe and that's without any mods. From looking at some stuff on the web a mild build (cam and better heads) would get the tbi up to the 250+ hp. That over 100 more hp from stock and more than enough for what I want.

 

[Kurtis]

You really do feel the extra 100 ft lbs of torque. I thought I would build my motor later down the road but I've never felt the need to do it. It'll hold 75 up grades even with the 35s and stock gears. 4.56s, 35s and the auto would be the perfect combo. I have the gears but for now it is sitting at my house in Arizona and I only get back 4-5 times a year. My place in Ohio only has a 2 car garage and I can't bring myself to let it see the salty roads.

I was very happy with the swap. It was simple, reasonable and has been very reliable. It sounds nice to. For my driving it was a pleasant surprise how much better it did on gas. I went from 10-11mpg trying to do AZ highway speeds with the 2f to 13.5-14 around town and 15-17 on the highway. 15 at 85 and 17 around 70-75.

 

[tclark]

For the record the reason I'd rather the 6.0 short block is because it's just a better design with many improvements over the old school small block, not for the power I couldn't care less about high horsepower; I just want as durable and simple as possible. Most of the trucks I've owned have had the 5.7 TBI and I have no doubt it'd be great in a 60. And it could pretty easily be made to have way more power than I'd ever want or need----it has plenty of potential too.

 

[lehiguy]

Stock Vortec 350 heads (if they are not cracked) flow very, very well, and they flow very well at low valve lift. They have good CR with flat top pistons. I was very pleased with the torque I had with these heads. In contrast the stock TBI heads are the worst flowing heads GM ever made for a small block. The TBI motors were reliable but gutless. A TBI system can be modified to support much, much more torque and HP than the stock TBI 350s ever dreamed of and still be just as reliable, but that is something you have to build and tune yourself, your not going to find that in the wrecking yard already bolted together. Now that I think about it, even the TBI 454s were disappointing in the power dept.

 

[ntsqd]

My bad, I said "Vortec" when I was thinking "early TBI". The early TBI heads (all that I have any familiarity with, no idea if later are different) have a very odd 'ramp' in the intake ports. Promotes turbulence and swirl which is good for a more thorough burn, but isn't so great for flow.

 

[norsk]

My bad, I said "Vortec" when I was thinking "early TBI". The early TBI heads (all that I have any familiarity with, no idea if later are different) have a very odd 'ramp' in the intake ports. Promotes turbulence and swirl which is good for a more thorough burn, but isn't so great for flow.

I thought that was the case.

A pic is at http://www.customclassictrucks.com/...ylinder_heads_small_block_chevy/photo_02.html

of the TBI "swirl"

and below

dougbert

 

[Gumby]

In addition to the reliability and ease of use of a stock system cooling is a big deal off road as well. Lots of idling, lots of low speed cruising. High horsepower, balanced on the edge of a razor engines are not going to be happy. Don't be that guy who stops the group every half hour to cool down.

200hp and good gears is plenty. Almost as important as the added power is the 300# less weight from a 2F. I don't really ever need more power. More gears I could always use, but not more power. How many 22REs are out there doing great on the trail with 80hp tops?

 

[ntsqd]

Hey now, my 22R makes at least a hunert HP!!! On a good day with good air, going downhill, with a tailwind....

 

[SNLC]

Only reason I could see cooling being an issue is if there is not good air flow through the rad.

I had a ramjet in a 60 and had cooling issues. Only when working the truck real hard or out on the HWY climbing grades. The P/O or whomever did the swap just hacked up the stock rad shroud. The fan was also more out of the shroud than half way in as it should be. Got a guy to make me a two-piece shroud out of aluminum. No more problems at all.

On the Cruiser I have now, 97 Vortec, zero cooling issues. I let it idle for 30 mins and it has no issues. I drive it hard, no issues. The temp never moves at all, just like my 3-Chevy work trucks. The shroud on this one is also hacked up a bit, stock shroud. But the fan is where it should be in the shroud and it pulls lots of air. Again, zero cooling issues with this one.

Cheers

 

[lehiguy]

My bad, I said "Vortec" when I was thinking "early TBI". The early TBI heads (all that I have any familiarity with, no idea if later are different) have a very odd 'ramp' in the intake ports. Promotes turbulence and swirl which is good for a more thorough burn, but isn't so great for flow.

Toyota did the same thing with the 22R head. The 20R head flowed significantly better even with smaller valves. The Vortec heads create cylinder turbulence by virtue of the combustion chamber's shape. GM considers them a "fast burn" head, requiring less ignition advance to achieve the maximum cylinder pressure at the magic 15 degrees ATDC. Less ignition advance means less resistance at the top of the compression stroke which in turn means more power. They really are great heads for the money. Wrecking yard pieces should be carefully inspected for cracks though.

 

[Off Duty]

This.

Elbert has my take on it too. The further from stock the less reliable.

Totally agree. Whether on the trail, or on the highway, I hate it when my rig is broken down!

...If you want a better head for a 5.7 (TBI or Carb'd) take a good look at the cyl head used on the 5.7 TPI Corvettes.

Having owned an 87 Corvette with the 5.7 TPI, I can attest to the torque of these engines as well as the reliability. They (GM) didn't call them "torque monsters" for nothing
Great low end, and still a pretty decent top, although, IIRC they stopped breathing worth a s**t (in stock form) around 5k (it's been a while).

Dependable motor too.

A set of these heads on a ~9:1 SCR 383 would be an awesome engine for off road no matter what fuel and spark system it has.

I think I'd have to agree

 

[norsk]

Found some other articles from my research on Vortec in my archives:

The following thread elsewhere, describes a tremendous amount of information on Vortec history, operations and characteristics.
I ponder if copying and pasting the posting here would be good to do, in case the link breaks in the future:

http://www.nastyz28.com/forum/showthread.php?t=56505

dougbert