TBI 350 Power Upgrades

[black dawg]

How did we go from helping a stock tbi 350 run a "little" harder to this? A mild cam, is a big step up from the tbi cam, and any cam that is within the easy to tune range, will be well within the limitations of the swirl ports.

 

[Bent77]

I'm out

@aglinks
Anything you need, let me know. If you like that spacer, send me your address. Ill give it to you

 

[Bent77]

How did we go from helping a stock tbi 350 run a "little" harder to this? A mild cam, is a big step up from the tbi cam, and any cam that is within the easy to tune range, will be well within the limitations of the swirl ports.

Someone up above got butt hurt. You're right online with what @aglinks was trying to accomplish under budget

 

[1-ton]

Do you happen to have a part number for your cam? Also, did you get a different chip for the computer to run that setup?

The part number is 12-304-4. I am running the stock chip for now. You can get away with not having to tune the chip with this cam, and still get a mild increase in performance. Tuning a chip will get you more, but probably not enough to justify the cost and effort.

 

[sreidmx]

The part number is 12-304-4. I am running the stock chip for now. You can get away with not having to tune the chip with this cam, and still get a mild increase in performance. Tuning a chip will get you more, but probably not enough to justify the cost and effort.

I run a hypertech 49 state chip, it basically cleans up the stock tune down low and adds some timing, the blm is damn near dead on 125 while driving around where the stock chip likes to float 115 or so. It definitely helped..

 

[skunked]

Needs a big block.

 

[1-ton]

I run a hypertech 49 state chip, it basically cleans up the stock tune down low and adds some timing, the blm is damn near dead on 125 while driving around where the stock chip likes to float 115 or so. It definitely helped..

I am going to have to look into that chip. I do have Tuner Pro R/T with all the proper .bin .adx .dfx files, in order to communicate with my ECM, so I can see how that chip performs.

 

[sreidmx]

I am going to have to look into that chip. I do have Tuner Pro R/T with all the proper .bin .adx .dfx files, in order to communicate with my ECM, so I can see how that chip performs.

Back to back there was a noticeable change in throttle response and midrange. The stock chip was dialing in 16 Degrees of timing at idle and the HT chip was 21 degrees. Makes the off idle torque a lot better.

 

[1-ton]

Back to back there was a noticeable change in throttle response and midrange. The stock chip was dialing in 16 Degrees of timing at idle and the HT chip was 21 degrees. Makes the off idle torque a lot better.

I went to Hypertechs web site, and they do not make a chip for my truck because of the 4L80E overdrive trans my truck has.

 

[1-ton]

Buddies L05 as of today looks like it's on it's way out, can't find much about any potential diffrerences, but I notice there were 2 and 4 bolt L05 crate engine replacements GM sold, but the 4 bolt is discontinued.

No idea what VIN code his is, but my guess is that is related to emissions/GVWR, since the 2/4 bolt difference was based on GVWR apparently.

When I bought my GM Goodwrench engine, a guy at a Chevrolet dealership that knows his stuff told me that GM was getting ready to discontinue the 4-bolt main TBI swirl-port engine. The only 4-bolts left on the shelf at the time where the 8.75:1 swirl-port TBI engines. Once those where gone...that was it. My original engine was a 9:1 compression 4-bolt main TBI engine that was discontinued in 2007. I ended up buying a 2-bolt main TBI engine that had the same 9:1 compression as my original engine. I still have my original 4-bolt main engine. I plan to build an engine with the block some day. The original swirl-port 64-CC heads on it are junk.

 

[skunked]

Needs a big block.

preferably a 8.1L

then you don't have any of these silly TBI vortec head debates.

 

[sreidmx]

I went to Hypertechs web site, and they do not make a chip for my truck because of the 4L80E overdrive trans my truck has.

Bummer.. mine has the 700r4 without the electronic control.. so maybe that's a special chip?

 

[dyeager535]

I went to Hypertechs web site, and they do not make a chip for my truck because of the 4L80E overdrive trans my truck has.

Not to be an a$$, but unless hypertech has done a complete 180, you aren't missing anything. Since the invention of CCC/OBD1, hypertech chips have bumped timing up a ridiculous amount, then told you to run a colder thermostat because the timing is way too much for the chambers.(Edit: I remember WAY back when people started being able to read chips...the Hypertechs of that time didn't even change fueling. It was scary.)

That added timing might really help with acceleration, I don't know for sure, but with Tunerpro, there is no reason you couldn't increase timing in the same areas, without having to change the thermostat. GM was pretty conservative with the TBI tune, but they were the ones that had to warranty any failures, and 128BLM's unloaded on flat ground is not what it would be while pulling a 10,000lb trailer up a mountain, and why you might get pinging under the latter conditions. Those low BLM's are giving you a margin for extra engine load, temp, weak gas, etc. They may be excessive margins, but they exist for a reason.

 

[sreidmx]

Not to be an a$$, but unless hypertech has done a complete 180, you aren't missing anything. Since the invention of CCC/OBD1, hypertech chips have bumped timing up a ridiculous amount, then told you to run a colder thermostat because the timing is way too much for the chambers.(Edit: I remember WAY back when people started being able to read chips...the Hypertechs of that time didn't even change fueling. It was scary.)

That added timing might really help with acceleration, I don't know for sure, but with Tunerpro, there is no reason you couldn't increase timing in the same areas, without having to change the thermostat. GM was pretty conservative with the TBI tune, but they were the ones that had to warranty any failures, and 128BLM's unloaded on flat ground is not what it would be while pulling a 10,000lb trailer up a mountain, and why you might get pinging under the latter conditions. Those low BLM's are giving you a margin for extra engine load, temp, weak gas, etc. They may be excessive margins, but they exist for a reason.

Its what the truck came with, I wasn't saying it was awesome, it was simply a point of experimentation on my end, and Before I bought a chip burner and loaded tuner pro I would swap the Ecm to something else.. at least that way I am not fighting the lack of tech to get what I want out of it.
Hypertech isn't good or even something I would buy.. fyi

 

[1-ton]

Not to be an a$$, but unless hypertech has done a complete 180, you aren't missing anything. Since the invention of CCC/OBD1, hypertech chips have bumped timing up a ridiculous amount, then told you to run a colder thermostat because the timing is way too much for the chambers.(Edit: I remember WAY back when people started being able to read chips...the Hypertechs of that time didn't even change fueling. It was scary.)

That added timing might really help with acceleration, I don't know for sure, but with Tunerpro, there is no reason you couldn't increase timing in the same areas, without having to change the thermostat. GM was pretty conservative with the TBI tune, but they were the ones that had to warranty any failures, and 128BLM's unloaded on flat ground is not what it would be while pulling a 10,000lb trailer up a mountain, and why you might get pinging under the latter conditions. Those low BLM's are giving you a margin for extra engine load, temp, weak gas, etc. They may be excessive margins, but they exist for a reason.

I was thinking of just trying a Hypertech chip (if they had one) out of laziness. To change any factory chip specs on my own, I have to have a burner and blank chips for that. I would be able to look at what the Hypertech chip was doing with my Tuner Pro, and If I did not like it, I could remove it.

 

[dyeager535]

If you google something like "hypertech chip garbage" (or crap, etc) you'll probably find the posts I read quite some time back. Maybe on thirdgen.org. As I recall, it was all increased timing, that was it. A complete ripoff.

https://www.thirdgen.org/forums/tpi/87511-jet-performance-chip-stage.html#post3868464

https://www.thirdgen.org/forums/dfi-ecm/648160-info-about-hypertech-chip.html#post5254539

At least on some applications there were some changes, but GM had different programmings for *everything* (gear ratio, trans, displacement, etc), so any differences could be accounted for based on which chip Hypertech was using as a base. Or they might have made some changes. I saw a suggestion on one of the posts to just turn your distributor advance up a hair...like 2-3* and get the same benefit.

 

[aglinks]

Sending my oil sample off to blackstone labs today. The truck has developed a knock on startup that lasts for about 10 seconds. It does it like every 5th time and doesnt seem to matter if its hot or cold. I guess its good that I havent ordered any parts to hop it up yet.

 

[aglinks]

Have you considered a GM crate L31 replacement? Good heads, roller cam, warranty. Under $2k.

You will still need either a Vortec-specific TBI intake, or a carbed Vortec intake and TBI adapter, plus a chip burn, and those won't be cheap either.

I doubt 10-15HP is going to get you what you want. Just my thinking. Would be nice to do a dollar per horsepower comparison, which is going to be arbitrary because most HP numbers are bunk, but it would be something.

Can never help myself when it comes to numbers:

L05 Crate: $10.14/hp
L31 Crate: $7.84/hp
L31 Heads: $25.60/hp
Headers: $4.80/hp
Cam: $4.13/hp
Intake: $23/hp

The two crate engines were just what I found quickly as an advertised price, and they sound about right. The heads are summits price for a pair. The headers were the cheapest small block long tubes summit listed for a Suburban, the cam was the second cheapest with no regard for performance, just cost. intake is the only TBI one Edelbrock makes. You can get cheaper by running carb+adapter I expect. Probably half that?

The numbers I used were based on generally accepted numbers, at least by me. Respectively, 190, 255, 25, 25, 15 and 15HP. Just don't forget, the L05 starts at 190HP. Adding 40HP doesn't get it to the L31 HP level.

Of course,to keep it simple, that ignores everything else that will skew those numbers. Gaskets, chip burning, exhaust work, timing chain, bolts, etc.

Besides the intake, would anything else need to change to bolt in an L31?

 

[dyeager535]

Besides the intake, would anything else need to change to bolt in an L31?

I can't think of anything major, but my memory stinks.

Physically the exterior dimensions/bolt holes are all the same, so none of that changes. Accessories all bolt on the same way, fuel lines on the back of the block will bolt up, motor mounts the same, exhaust manifolds the same, flywheel the same (both single piece main seal engines).

The timing chain cover is plastic and designed for a crank sensor, I solved that by just sticking a junkyard crank sensor in the hole.

Doesn't come with a dipstick, but pretty sure the TBI ones will bolt on too.

Auto trans, someone might want to comment on how that may or may not change the geometry for the TV cable, that is *critical* to not killing a 700R4.

Tune will be needed for sure. I'd not think I could get away with running it even for a bit without the proper tune.

 

[aglinks]

I was finally able to record the odd noise the engine started making. The engine makes the knock/tick every 5-ish cold starts and the noise never lasts more than 10 seconds. There are two videos for convenience, the first video shows the start, the noise, and the transition to normal running. The second video is a cut of just the bad noise (in this particular case, the noise was only made for about a second). Does this sound like lifter tick? Or something else?

Longer Version:

Super Short Version: