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tbi performance, whos done what with good results

bassmannh

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my blazer runs good, but would like a little more power for towing my bass boat, and maybe some better milage too, 87 k5, new gm engine, not rebuilt, 33 1050 15 bfgoodrich AT, 3.73 12 bolt rear, dana 44 front, 700r4, 208, stock exhaust, k&n air filter, stock chip and distributor, bosch platinum plugs, accel cap, rotor and wires. I would like to tune for more power, thinking about shorty headers, free flowing cat, flowmaster, tbi spacer, injector spacer adjustable fuel regulator, cam, chip, manifold,4.56 gears. Would like to hear what you guys are running, what mods you did that worked out well, and what didnt? Details PLEASE /forums/images/graemlins/ears.gif
 

Hardcore

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4.56s are a little tall. Check ot TurboCity, they make lots of stuff for the TBI. Get yourself a set of Edlebrock TES or Doug Thorley headers. If you don't mind tearing into your motor, do a cam swap, lots of manufacturers make good cams for TBI's. You can also pick up some power with a better intake manifold like one of the ones Edlebrock makes.

Thunder will probably chime in here shortly but if he doesn't then send him a PM, he knows TBI motors and has been a huge help to me /forums/images/graemlins/thumb.gif
 

smokkey1

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/forums/images/graemlins/ears.gif /forums/images/graemlins/ears.gif /forums/images/graemlins/ears.gif /forums/images/graemlins/ears.gif /forums/images/graemlins/ears.gif



justin /forums/images/graemlins/burb.gif
 

detailer03

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I have the edlebrock headers with 3" gibson cat back.
I have 33x12.50 15's. I also run a K&N filter. What I did was open up the air intake in the factory air breather assm.
I also have a new GM 5.7, aka 350 CI. I have heard mixed things from the TBI spacers etc. Some say only a little HP, while others say a big difference. I am still waiting to find someone who has already done it also.
 

zcarczar

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4.56's will work perfect with that combo. That way you can still use OD most of the time while towing and you will have more power. I personally run 4.88's with 35's and tow a samurai around and it works awesome.
 

bigburban383

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A spacer will give you more low rpm torque (good for towing)

I would go with LONG tube headers not short for towing.
Long = Torque
Shorties = High RPM gains

Might as well drop a performance chip in there too.

Gears would be good for towing too, I agree 4.56 may be to low but you do have 33 inch tires and if you got overdrive you should be okay.
 

84_Chevy_K10

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4.56 is far from too low if you tow.

My tow rig has 4.10s, no overdrive, and 31s. If I had my way it'd have 4.56 or 4.88s so it could pull even harder.

If you want to tune for more power, start by getting those horrible Bosch spark plugs out of your engine and putting in the AC Delco ones that belong there.
 

scoutillac

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I've done the spacer and I like it alot. I also run 35's with 4.56's and wish I had 4.88's. It feels like a dog when towing. Granted it's not a race truck but it giddy up's pretty good without any added weight. At the scales empty I weight around 6500lbs. I want to chip it, but I'm unsure of the gains and the effect on my motor; since I don't know when it was rebuilt if ever. The odo reads 180k.
 

fad2blk99

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Something I wish I would have noticed before I bought my 4-into-1, 1-5/8" long tube headers, was Headman's Torque step headers. These headers start out @ 1.5" and increase to 1-5/8" about halfway to the collector. In a CHP article, 1.5 headers created the most low end torque out of ANY (including Tri-Ys), but do begin to fall off early. I think these torque step headers will give you the best of both worlds, IMO.
As far as TBI specific upgrades... I'm all ears /forums/images/graemlins/ears.gif /forums/images/graemlins/ears.gif /forums/images/graemlins/ears.gif
 

heavy4x4

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My TBI is running a K&N filter, tbi spacer, and good-flowing exhaust...nothing much else (yet /forums/images/graemlins/wink.gif).
I like the mods I've done so far. I can tell a difference. For having 167,000 on the ticker, it runs really well...fairly strong and very dependable.
The only thing I would want is more power in the lower rpms (like when accelerating and it up-shifts...I'd like more power as it's starting out in the next gear). And, I'd like more crusing power for the freeway. But, I can blame those problems on axle gearing just as much as I can a 167,000 mile engine.
 

fortcollinsram

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Well, I have a TBI 454. I will run through what I have done to it to make it suck gas and haul ass...

-Crane 2020 cam
-Flat Top pistons
-Roller rockers
-GMPP distributor
-Stock CR43TS ACdelco plugs
-MSD super conductor wires
-Injector spacer
-Doug Thorley Tri-Y headers
-Dual 3" pipes, Flowmaster 50's
-NO cats

I have also added a JET adjustable fuel pressure regulator that I canned TONIGHT in favor of a stock GM vacuum referenced fuel pressure regulator. The problem with my motor is the STOCK FPR couldn't supply enoguh fuel for my modified engine. So I turned to the JET FPR. Well the Jet is cool but you make a trade off. You either run nice and stoich at idle and run LEAN at WOT or run overly rich at idle and stoich at WOT.. Up until tonight, my truck was running a little rich at idle and a little lean at WOT.
The vacuum referenced FPR will see the high vacuum at idle and thus a lower FPR..As you open the throttle blades and vacuum decrease to near atmosphereic pressure at WOT, the fuel pressure will raise. I haven't finished the install yet but I will be sure to let everyone know how it work. You can check my pics in my sig. in about 30 min. to see pics of the Jet and the GM VRFPR.. I will also be installing a 4-wire O2 sensor in place of the facotry 1-wire unit...


My truck runs like a raped ape except for high rpm, WOT situations b/c it has been running quite lean up top. I hope to change this with the new FPR and O2 sensor...

Chris
 

fortcollinsram

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3685Jet-FPR-and-VRFPR.jpg


3685VRPR03.jpg


more pics are now in my album in my sig /forums/images/graemlins/thumb.gif
 

Thunder

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Here's a list of my TBI mods on my 89 K5 with 90k on the clock.
Throttle Body:
TB spacer- open plentium kind They make more power than the kind with two holes.
Injector spacer- works good adds a few CFM air flow
Velocity stack- replaces the stock spacer that goes between the TB and air cleaner- definatly works good /forums/images/graemlins/thumb.gif
Flow matched injectors- /forums/images/graemlins/thumb.gif
Adjustable fuel pressure regulator- This is a must have if you want to run headers, intake, cam or other mods.
K&N filter in stock aircleaner with all the hot air stuff removed. Dont use open element aircleaner housing with TBI you will acually loose power. TBI needs the cold air from the front of the engine.

Ignition:
Performance distributors Screamin demon coil and Dyna mod- works just as good as MSD 6al but lots cheaper.
Taylor spyro pro wires
acell cap and rotor
Good ol Ac delco plugs. Dont like platinmum plugs had too many troubles with them.

Exhaust:
Edelbrock TES flowmaster 70 series muff and dump. Used to have full exhaust but I lost it somewhere on the rocks. /forums/images/graemlins/woot.gif /forums/images/graemlins/woot.gif

I also tow a 18' I/O fishing boat. I usually put at least 1500 miles a year or more draging it behind my K5 to the North Cal coast and back to Nevada. I run 33" tires 3.73 gears 10 bolts with lockers. However, when I do long distance towing I throw a set of 31" highway tires/wheels on. It just tows better with smaller tires and lower to the ground.Plus its a lot easier and cheaper to swap tires than gears /forums/images/graemlins/wink.gif
The above mods work well for me I have lots of power in the hills and can get 15 MPG flat towing on the interstate at 65 mph. Of course my fuel milage takes a big dump when I get in the hills.
I used to think aftermarket chips helped but I have found thru expermentation that you can get the exact same results bumping up the base timing 4-6 degrees and running preimium.(unless you run too much cam, compression ratio, or free breathing heads then you will need to get a new chip burned)
If you have a scanner you can set optimum timing by bumping up the timeing a little at a time and making full throttle runs with the scanner hooked up showing real time. Look for knock sensor counts. When you get them back the timing off a degree or 2 till they go away and you are set.
I usually get my fuelinjection stuff from:
http://www.turbocity.com
Or
http://www.cfm-tech.com
Both have everything you need to mod your TB. if you have not done so spend some time surfing around Cfm-techs site there is a wealth of info there on TBI and mods.
I have not added cam intake ect. My 350 just runs too good and tight to open it up. dont want to evoke any of Murphys laws. So i just figgure I'll leave it alone for a while /forums/images/graemlins/cool.gif
 

bassmannh

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Thanks to everyone who replied, I also would like to know how these mods affected TV cable adjustment and shifting characteristics,( if your running 700r4 that is).I dont want to cause problems with this, have heard of problem with running spacers changing ratio on cable pull, and problems with trans pressures the result.Check out "bowtie overdrives" if you would like some info on this, Thanks again.....><(((((*>...... /forums/images/graemlins/ears.gif
 

Thunder

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Thats why I like the 1/2" open type (Turbocity) TB spacers. They only raise the TB 1/2". All you have to do is let out the TV cable a couple of klicks to get the shifts back where they should be.
Those bigger 1" spacers can cause problems with the TV cable adjustment. Some even need to bend or modify the linkage mounts. I have even heard of people blowing their trannys after installing them and not adjusting the TV cable afterwards.
I have been running my 1/2" spacer for many years now with no tranny(700R4) problems.
 

heavy4x4

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My 1" spacer came with metal bushings and longer bolts that were used to lift the throttle bracket (the metal bracket the throttle cable and TV cable are attached to) up about 1/2 - 3/4" from the intake manifold. From there, you just adjust your TV cable according to the instructions found here. Everything will be back to normal as far as shifting goes.
 

fortcollinsram

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yeah BTW, I don't run a TB spacer on my 454 becasue my 4in tall open element air filter is only about 1/4" away from hitting the hood as it is..I will add a specer when I put my cowl hood on this summer...
Chris
 

bassmannh

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we are still all waiting to get the part# to that vacuum sensing fuel pressure regulator, and where did you get it Fortcollinsram? Thanks again for all the info to everyone. /forums/images/graemlins/peace.gif
 

duece21

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Heavy4x4 where did you get your spacer from? I got my entire setup from CFM. TBI spacer, Adj fuel regulator, Air flow enhancer, Injector spacer. It feels like it has more Low end power, but It's hard to tell right now b/c first to second is shifting at alot higher RPM now. If you give it any gas when it shifts it feels like someone is hitting me from behind. I need to look at it better tommorrow. You said that your kit gave you 1/2 spacers to raise the mounting plate. I wonder if I could just buy spacers and bolts to raise the plate b/c it looks like it only needs to raise up about a 1/2 inch to let the cables not have the arch they have in them and then adjust according to the web site you posted.
By the way, thanks for that web site /forums/images/graemlins/bow.gif I printed everything out and it should help alot.
Thanks
Jesse /forums/images/graemlins/waytogo.gif
 
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