Finally got around to pulling the trigger on getting my TBI rebuilt from Sean at SPR Performance. This is an original TBI from a late 80's 454 that I picked up from a member on the Performance Years forum. After sending them this greasy/dusty unit, this is what they sent back. I was overly impressed with how it came back. The turn around time was 2 weeks. It also came with fuel fitting o-ring gaskets, air cleaner gaskets and a printed assembly/setup manual.

-Throttle bores were bored to 54mm (bigger throttle blades).
-Throttle shaft thinned (more cfm).
-Base bored to match throttle bores.
-Fuel pressure regulator block-off plate installed.
-New genuine AC Delco sensors
-Injectors cleaned
-All hardware replaced with stainless.

http://www.sprperformance.com/

by https://www.flickr.com/photos/156619454@N04/, on Flickr

by https://www.flickr.com/photos/156619454@N04/, on Flickr

by https://www.flickr.com/photos/156619454@N04/, on Flickr

by https://www.flickr.com/photos/156619454@N04/, on Flickr

by https://www.flickr.com/photos/156619454@N04/, on Flickr

 

Wow! Thank you thank you thank you for the info... I need a new throttle body and have been looking into my options...

Have you installed the unit yet? Also.. Just curious how do you know they are ac delco sensors?

 

No, haven't been able to install yet. This is actually going on my Pontiac 400 that's getting controlled by a Megasquirt computer. It shall be interesting.

For GM TBI, I think this is about as good as it gets.

 

Just to be straight forward... you don't, or haven't in the past, work for them or have any personal interest in the business ownership?

 

Haha, no don't take the post like that. I know my pictures look very show-like but I have no business type of relationship with SPR. This picture is just in my room on my Harbor Freight desk that came with a light on it 😂

Below is picture of the Megasquirt computer I'm assembling for this setup. Just to throw this off topic a bit. That's Super Mario in the back as well lol...

 

You "forgot" to specify how much you paid for the TBI rebuild/modifications.

 

TBI rebuilds from SPR range from $300-$500 depending on what you want done. Boring for bigger throttle blades is the main thing that will jack up the cost. Most don't have to go all out like I did with mine. It's also cheaper if you send them your core. It was more expensive for me since I did not start with a core. Mine was a little bit more of a custom job since I had the base bored and milled. Contact dctrumpet for price quotes that you want a quote.

 

Yeah i need mine bored out to 46mm and want the top shaved all down like yours. My shaft is also bad because im getting sticky throttle blades staying open at 1-2%tps, i have to physically push the throttle closed by hand to idle lol (0 iac counts at idle ). Im just curious about the actual sensors... if they are truly AC delco or not.

Oh wow that name sounds familiar...

 

I don't want a quote.

I want to know how much YOU paid for the product you're posting photos of.

 

I just spoke with Sean at SPR on Facebook. The Delco sensors he supplied me are actually NOS (new old stock) GM sensors.

 

Here you go...

https://www.ebay.com/itm/231611295109

 

Looking forward to hearing about how it runs.

 

Thats interesting... Not trying to sound rude just that looks like diff sensors than mine. And do they use diff plugs? So you have to splice in new connectors?

 

I'm not the biggest TBI expert but I know there were different sensors on the TBI's. I'm not sure if it's early vs late and/or SBC vs BBC. Mine is an earlier style (80's) model.

What year is your TBI? BBC or SBC?

 

Thats true mine is sbc and 88, but for your application are you going to have to splice in new connectors or is it plug n play for your harness?

I might just have him do the whole rebuild except the sensors. The throttle body itself looks really really good and thats the main thing.

 

This setup is going in my '79 Trans Am 400 4spd. I bought the diyautotune carb-to-efi kit as previously pictured in the thread. It pretty much comes with everything to wire up the computer and efi related parts. Even has a relay/fuse board so everything goes in one spot. Attached is pretty much how a Megasquirt MS2 gets wired up. It looks complex but it's easier once everything is in front of you.




Basically, I'm converting my originally carbureted Pontiac 400 engine to efi via the BBC TBI unit, '81 Pontiac 301 distributor and Megasquirt. The distributor is a 7-wire computer controlled HEI.

I'll have to wire up the sensors but it's nothing too crazy looking. The IAC on our 80's TBI's is a 4 wire setup and the TPS is a 3 wire setup. Coolant and IAT sensors are two wire sensors.

 

Ops ok yeah sorry forgot you are putting this in a 79, not a third gen.

Either way the main point is the throttle body and that thing looks damn good. Keep us updated!

 

Hopefully I'm fortunate enough to make meaningful progress soon. I haven't driven my car in a number of years since turning it into a project. One thing interesting thing I have for this setup is the Cadillac intake assembly. I have some interesting ideas for building a ram air setup at the moment.

 

Nice i bought the same caddy bonnet the other day at a local junkyard! Im trying to debate how to plumb it up as well... I might wait and run it with this http://www.hawksmotorsports.com/air-...-w-k-n-filter/

and this https://americansportscar.com/produc...-1992-ram-air/

Yet once again this is 3rd gen haha.

 

What Caddy did that intake come from? That's the nicest-looking, smoothest carb hat I've ever seen. I want one.

It's almost like it was designed by engineers instead of aftermarket idiots.

 

Early 90's Cadillac 4.5/4.9 engines. I have an extra if you want to buy it.

 

I have some local sources (Treasure Yards) although shoot me a price via PM including shipping. I can pay via PayPal or USPS money order.

My guess is that shipping will be expensive due to the bulk.

 

I suggest going to the junkyard first if you can find a setup and pull it off a car. I won't be able to match junkyard pricing. These intake setups are from port injected Cadillacs. The throttle bodies on those engines look like they were casted by whoever did the TBI's. They literally look like the Rochester TBI's but with no injectors. You'll see what I'm talking about.

 

Yeah i thought that was funny when i seen it at first as well. Just missing the injector pod!!


EDIT: on a side note i think i already found the throttle body im buying off SPR (dctrumpet) on ebay...

 

Awesome, good to hear. The SBC or BBC unit from SPR is a great deal when done up to the maximum specs. Tuning and other engine mods come next.

With a nitrous kit and computer than can operate it, you can potentially make a great amount of power. Most people haven't gone that far with these things though.

 

For 8 months my old G20 van had a single 2" bore marine throttle body, feeding a stock LT1 cammed 350 with Dart Iron Eagle 230cc heads and a Weiand 177 making about 7 psi on it. 4 transmissions later I pulled the blower off it. Under boost I was feeding the engine with 61# 350 injectors running at 50 psi. 4:1 rising rate regulator that was set at 22 psi without boost/vacuum. With vacuum reference the idle fuel pressure was about 15 psi. At 4:1 rise and 7 psi the fuel pressure jumped 28 psi above the set point. 61 lb/hr injectors at 50 psi can feed well over 500 hp. The 2" bores were also not restrictive at well past 400 hp.

I was getting 7 psi at 5,500 rpm and running 24° of timing on 93 octane at about 11:1 afr. At 6,500 rpm it would run almost 9 psi but I really kept it down in the 5,500-6,000 rpm range with the stock rotating assembly. May not seem like a powerful engine but with 2.08/1.60 valves and 230cc intake ports the Darts were flowing in the 270 cfm intake /210 cfm exhaust range at 0.510/.520" lift the cam was giving with 1.7:1 rockers. It would idle dead smooth at 600 rpm in Drive with the a/c on. It would absolutely destroy the P295s on the back despite 3.08 gears and the stock 1,600 rpm stall speed in the 4L60E. It also killed hard parts in 4 different 4L60Es in 8 months. I bet it would have been a fun setup with some forged pistons and a 125 shot on top with a well built TH400.

I ended up running the same engine setup down the track after removing the blower. With 18cc dished pistons and 72cc chambers it was in the 8:1 compression range. On 87 octane running 38° timing from 2,400 to redline it ended up running about 8.70 in the 1/8. Similar to a LY6 6.0L the huge head ports were very doggy without the blower under 3,500 rpm which lead me to swap the heads out for Vortecs not long after. I was able to put the Thorley Tri-Ys back on as well and go away from the stock manifolds I was forced to run with the Dart angle plug heads.