In this video I will be Dyno testing my 1994 GMC Sierra to see how much HP it puts down to the wheels stock. and we will be testing if throttle body spacers add power on a TBI engine
So ive got a 95 4.3. I recently installed the throttle body spacer, a injector spacer, and i used Spectre's stud kit to go from the twin air cleaner studs to the single air cleaner stud. Motortrend did a video testing different styles of air filters and i seen that the spectre air cleaner with the filtered top actually increased power by like 3 horses so i bought one and after driving it for about a month and a half i can tell a difference in throttle responce and fuel mileage. I did give it 10 degrees in timing and that was a night and day difference. I dont think the spacer does anything by itself, but i think when it is accompanied with other parts and a little bit of help it does add a little bit of pep to the step.
I have a 94 Yukon & I'll suggest before giving up, the spacer you want is made by " High Velocity Heads " but know this... the secret to getting a few extra ponies out of a TBI is getting more air out the exhaust. Magnaflow makes an excellent performance Y pipe with cat convertor that bolts right up. Add both of those together with a set of 1.6 ratio rocker arms on your stock cam & you'll feel that in the seat of your pants. Computer won't have a problem with any of it. More bottom end snap off the line, a nice torky sweet spot from 2000-2500. 2500 to 3500's not to shabby either. You gotta let her breath, no one mod will get you what you want. PS. to avoid poor cold start conditions stick the upper base gasket to the bottom of the tbi with a little RTV for proper IAC performance. (so not too lean) Need that with that style of spacer.
Thanks for your testing on the GM T.B.I. I just bought a rust free G20 with a 350 TBI. Runs ok but always looking for more, I flipped the lid and gave it 10 degrees more base time and that woke it right up. Header and 3 inch pipe are next.
Had guys say they made same trip 3 time. (2) without and (1) with and seem a drastic improvement in fuel economy. He went into the impression of it being snake oil. But had one from a spare engine he had bought so decided to test for himself and said he gained about 3 mpg
Cut the center divider so that it has an open center. Open center spacer and remove the collar around the injectors using a power bowl type setup. Was worth 10 hp at the wheels on my G20 van.
@@jastram6pac Google Trans-Dapt 2633 and look at the picture of it to get an idea of how to open the spacer between the bores. I put my spacer in the jaws of a vice, cut the center out with a metal blade in an air powered jig saw and then smoothed it out with a sanding roll in a die grinder.
@@parker12c What are you talking about, it is almost no work to put an open center TBI spacer and a powerbowl between the air cleaner and TBI. It is 3 bolts and a wing nut. The 350 that was tested on made 200 whp and 300 wtq prior to those changes. It was outperforming my stock L31 350 with only headers and chip tuning as it was. 10 hp on a 200 hp engine is a 5% power gain for less than $50 at the time. That engine was rated 185 hp and 300 tq at the crank, made maybe 140 hp at the tires stock. Headers, TBI spacer, power bowl and chip tuning had it up a solid 70 hp compared to the stock setup.
@@chrisreynolds6520 The fact you would even look for 200 hp in 2024 is embarrassing. It's "185" new from factory - not your tired ass motor. %5 gain would be impressive if the baseline wasn't so low to begin with. And again proof or stfu.
So many people say to do the lid flip. I don't see how sucking hot air from your engine compartment is better than the cold air it pulls from the fender/wheel well. My tubes don't seem that restricted compared to intakes I've replaced in the past.
Say what you want. I took mine in to a shop to get A/C work done. Was driving up the same grade I do every morning wondering why it was lacking it’s usual torque popped hood a couple days later and Re flipped the lid. Not everything shows in the dyno
Pretty interesting but I do need to say that when you do the lid flip trick you're getting a lot of hot air from the engine compartment and that's not being shown here by having the hood up in a big old fan blowing on it
Man just debunked so many myths about the lid flip and spacer. Im glad someone actually did this with an actual dyno and full stock great video man Like well deserved! I ahve a 94 chevy tbi as well but its a c1500 so it isnt as heavy as the 4x4 so the weight will make a difference for sure for sure will keep up with the journey.
Heh ,good on u for being truthful about your experiment, you,ve saved a lotta people a lotta money and dissapointment,so thanks for that ,hope u have better luck with the next one
Yea but people that know much think that the difference should be at wot like long tube headers, every nut sucker swears by long tube headers yes they make more power at full throttle but they feel weaker than shortys at part throttle. Just my point of view ive raced and built many engines i care more for part throttle gain than full throttle gain if its full throttle those big mods should really add up.
Did I hear you correctly? 160 horsepower? That’s far worse than I expected a stock tbi to make. Makes me wonder what my 92 c1500 makes. Probably not any more. Thanks for the info! I saw your Facebook post in the group and figured I’d check it out. I’m hoping to see more videos on your 94.
I have read every where you're supposed to gain 10 to 20 horsepower with those I have never really expected them to make power in fact I kind of always thought it was snake-oil like you said in the beginning of the video I do believe they make your throttle more responsive but I believe that is absolutely it but I do a hundred percent thing that they give you a better throttle response but that is it
Thank you . This is info I have been really looking for. I'm pulling a 4700 lb travel trailer w a 92 Chevy 4x4 Suburban That has a factory Tow Pkg. 3.71 Rear Gears & a 5,7 Stock TBI. Unit is rated per GM for 6500lbs towing Info says 220HP at crank & Peak torque is said to be at 2500 rpm. I pull in Drive not OD. About 2700 RPM gets me 62 MPH on the HWY. I'd hate to put 6500 lbs behind it stock as it struggles with what I'm pulling. I really don't want to tow it at a faster speed so High rpm mods are not what I'm looking for . More Torque & Hp under 2800 rpm is what I'm searching for. Replacing the Clutch Fan with Electric units is probably worth something. Thank heavins I only have to tow it North 1X & then Back 1x per season as I have a spot to leave it over the summer. Keep it coming you have my attention.
I did actually, I had the spacer installed for about three weeks before and then took it off mid dyno session to give is the best chance to make a difference,
These TBI engines were designed to do only 1 thing….pass emissions. This engine family is an example of the big car companies designing emission friendly engines from the ground up. In the 60’s engines were focused on power. In the 70’s they detuned the powerful engines because of the gas crisis. In the 80’s they focused in passing emissions and becoming electronic. In the 90’s they started power again. In the 2000’s they finally figured out a way to have power and be clean. These TBI engines are basically 80’s engines. You can’t really get much out of them.
Never in my 30 years of workin on obs trucks have i seen anybody use a torque wrench for 12 ftlbs....and the spacer does not make horsepower...but does help in higher rpm as in highway travels...
If you're not going to do a performance carburetor, a performance intake and heads with a cam it's pointless technically with a performance intake and carb with a good cam it might help with fuel atomization and flow fuel air mixture through the intake better and make more power if your goal is 300-500 hp on a sbc
Lol a spacer raises the drop so without other things added it won't do much or anything at all. Most effective is to put a stronger regulator spring and adjuster to keep 15,psi on the TBI.
@@parker12c not so a spring raises fuel pressure and amount and bore it out and you could get 50 more CFM. There are plenty of tbi builds just outdated now with efi.
@@jeffpalmer2192 Then what? the pre-loaded read-onlys from the ecm do nothing with it - like I SAID "there's nothing to add that justifies doing anything", why don't you learn to read.
@@parker12c I think your giving the stock fuel map to much credit. If you make the injectors run at higher pressure you're adding more fuel. Then you add air. Busy seriously man look up people making 500hp from tbi 350s. It more than doable.
166 horsepower at the real Wheels sounds about right as far as factory specs go considering that's only probably a 230 horsepower engine so 166 at the rear wheel with all the miles that thing has on it because it is a used truck to me that sounds about right 👍
It's good for about 1-2 HP. BUT this is on an old tbi ecu. You can't run it on the dyno without adding mileage. It wouldn't of shown much improvement instantly. You need to unplug the batteries,drain the system completely by touching both positive and negative cables off the battery let it sit that way for about an hour. Then plug it in after the tbi spacer install. Turn it on and let it idle for about 10 minutes. Then go drive it slowly through the gears let it relearn. Itll make a couple ponies difference. And about 1 mpg difference. Just don't expect to get knocked back in the seat.
I'm surprised the lid flip did nothing. I'm not surprised the spacer did nothing. Try an injector spacer. Try a salad bowl for an air cleaner with a k&n filter top
Throttle body spacers are designed to give part throttle gains, not full throttle which is why it wasn’t reflected on the Dyno. While the spacers aren’t overly useful on most applications there are two that the Throttle body spacers work exceptionally well on… 4.0L Jeep engines (97-06) and 88-95 350 TBI engines. The fact this dude thinks testing a throttle body spacer on a chassis Dyno was a good idea speaks volumes towards his remarks and credibility. 🤡
