350 TBI Performance Options?

[Tony_SS]

I have a GM crate 350 with TBI setup.

What are some fairly simple upgrades get a few more ponies and torque out of it?

[eventhorizon66]

Can you elaborate on you specific set up?  What crate?  The universal Goodwrench 350 or Goodwrench L05 replacement?

In any case a nice free flowing exhaust is always a good place to start.  Quality headers, 2.5" dual pipes,  h-pipe or x-pipe, high flow cats (if you need cats), and magnaflow or dynomax ultraflo mufflers.

[Tony_SS]

I dont know.. I think it might be a universal Goodwrench 350. It has centerbolt valve covers too. I need to run some numbers.

Outside of the exhaust.. what else, to the TBI, engine or programming?

[jimbo]

Throw a carb on it.  LOL, I am joking, thats the cheap way out.  There are many things you can do while keeping your tbi.
http://www.chevyhiperformance.com/techarticles/148_0307_late_model_tbi_trucks_power_upgrade/index.html
http://www.ehow.com/how_4623673_build-high-performance-tbi-engine.html
http://www.cfm-tech.com/GM_tbi_tuning_tips.htm
http://www.cfm-tech.com/catalog/gm_tbi_performance_parts___accessories_126905_products.htm
http://www.tbichips.com/
http://www.fullsizechevy.com/forums/general-discussion/performance/418481-ol-salad-bowl-tbi-modification-how.html
http://www.thirdgen.org/techboard/tbi/391406-budget-tbi-buildup.html

[Tony_SS]

Wow, thanks jimbo, that ought to keep me busy for awhile!

[jimbo]

Oh, I almost forgot my favorite source for parts:
http://www.summitracing.com/search/?keyword=tbi&dds=1

A friend of mine swears by the "salad bowl" on his tbi z71.:
http://www.summitracing.com/parts/HYP-4001/

[Jim Rockford]

Biggest restriction  for TBI engine is the HEADS.. you can put all the exhaust in the world on it, they heads will still not flow.you can see the ramp blocks half the port.

Compared to a regular heads intake port..

[eventhorizon66]

Biggest restriction  for TBI engine is the HEADS.. you can put all the exhaust in the world on it, they heads will still not flow.

...but at least everything downstream of the heads will.

It's understood that TBI heads' flow numbers suck.  But a full exhaust can net 25 hp or so without touching the heads.  And if you do decide to replace the heads with higher performing units, it becomes even more crucial to relieve restriction downstream at the same time.  So, cutting exhaust system losses at an early stage in a performance build makes good sense.

He didn't specify how much power he was looking for, but he did say he was looking for some "fairly simple upgrades."  I don't think head swap or extensive head porting falls into that category.

[Jim Rockford]

I've done headers and exhaust on LO5's...It doesn't help.if you can't get more air in, you don't have to worry about getting it out.

[jimbo]

I've done headers and exhaust on LO5's...It doesn't help.if you can't get more air in, you don't have to worry about getting it out.

You must be kidding with the "it doesn't help", bit.  Just because the gains aren't as large as some other applications doesn't mean that every dyno in the world won't disagree with that, lol.

[jimbo]

Biggest restriction  for TBI engine is the HEADS.. you can put all the exhaust in the world on it, they heads will still not flow.

...but at least everything downstream of the heads will.

It's understood that TBI heads' flow numbers suck.  But a full exhaust can net 25 hp or so without touching the heads.  And if you do decide to replace the heads with higher performing units, it becomes even more crucial to relieve restriction downstream at the same time.  So, cutting exhaust system losses at an early stage in a performance build makes good sense.

He didn't specify how much power he was looking for, but he did say he was looking for some "fairly simple upgrades."  I don't think head swap or extensive head porting falls into that category.

I couldn't have said it any better.

[chevymotocross]

There are a few options. I agree that bolt-ons help a good amount (headers, exhaust, tbi mods, spacer intake, etc), but the main weakness, atleast of the L05 350 and L03 305, are the heads and cam. Of course these can be changed, but now you run into tuning problems. Your best bet is to either learn to tune and data log yourself, find a good tuner who knows TBI, or, forget the TBI altogether and get a carb.

[VileZambonie]

Tuning a tbi is cake

[Jim Rockford]

Biggest restriction  for TBI engine is the HEADS.. you can put all the exhaust in the world on it, they heads will still not flow.

...but at least everything downstream of the heads will.

It's understood that TBI heads' flow numbers suck.  But a full exhaust can net 25 hp or so without touching the heads.  And if you do decide to replace the heads with higher performing units, it becomes even more crucial to relieve restriction downstream at the same time.  So, cutting exhaust system losses at an early stage in a performance build makes good sense.

He didn't specify how much power he was looking for, but he did say he was looking for some "fairly simple upgrades."  I don't think head swap or extensive head porting falls into that category.

I couldn't have said it any better.

Well all I can say is enjoy flushing your money down the toilet. I've only been hopping up carsand engines for 20years.. Sorry if my experience doesn't hold enough water for you.

[jimbo]

Biggest restriction  for TBI engine is the HEADS.. you can put all the exhaust in the world on it, they heads will still not flow.

...but at least everything downstream of the heads will.

It's understood that TBI heads' flow numbers suck.  But a full exhaust can net 25 hp or so without touching the heads.  And if you do decide to replace the heads with higher performing units, it becomes even more crucial to relieve restriction downstream at the same time.  So, cutting exhaust system losses at an early stage in a performance build makes good sense.

He didn't specify how much power he was looking for, but he did say he was looking for some "fairly simple upgrades."  I don't think head swap or extensive head porting falls into that category.

I couldn't have said it any better.

Well all I can say is enjoy flushing your money down the toilet. I've only been hopping up carsand engines for 20years.. Sorry if my experience doesn't hold enough water for you.

No problem, its difficult to make any unfounded theory, that can be proven wrong in one attempt, not leak like a sieve.