5.0 TBI LO3 dyno + 081 heads swap
 

Hey guys, just wanted to share.
I'm going to throw 081 heads on my Firebird among some other stuff, and decided to dyno it before and after.

So here are the results for a stock LO3 with few bolt-ons.
These are the engine figures, there are ~50hp less on the wheels.


http://s017.radikal.ru/i402/1507/ee/7263f2dc6c44.jpg

http://s017.radikal.ru/i428/1507/b6/99d831c6cf10.jpg

Re: 5.0 TBI LO3 dyno
 

460 TQ? Am I reading this right lol?

Re: 5.0 TBI LO3 dyno
 

Which bolt on made it AWD?

Re: 5.0 TBI LO3 dyno
 

On average, yes, did 3 runs.
But that is engine torque, there like 350 at the wheels.

Re: 5.0 TBI LO3 dyno
 

That would be the transfercase and axle from h1 alpha :lol:

Re: 5.0 TBI LO3 dyno
 

Thats crazy torque vs hp. Was it a pain to do awd? Have you seen that awd mustang?

I know guys, Its a mustang, but this thing is bad.

Re: 5.0 TBI LO3 dyno
 

That's NM Torque, that' like 339.8 ft lbs torque. Which is still impressive!

Re: 5.0 TBI LO3 dyno
 

Some photos of the stuff being put on.


http://s020.radikal.ru/i705/1507/a7/a038a13b1873.jpg
http://s018.radikal.ru/i523/1507/af/bfd807497d8f.jpg
http://s020.radikal.ru/i703/1507/3e/78c1feab156e.jpg
http://s017.radikal.ru/i441/1507/b4/f22064534653.jpg
http://s018.radikal.ru/i520/1507/31/a71ff5fde93e.jpg
http://s009.radikal.ru/i310/1507/af/3896966cdbb9.jpg

Re: 5.0 TBI LO3 dyno
 

http://s013.radikal.ru/i325/1507/6e/699cb1a7384f.jpg
http://s010.radikal.ru/i314/1507/02/a9b5b9827494.jpg
http://s019.radikal.ru/i629/1507/14/08db3ecf20f8.jpg
http://s020.radikal.ru/i720/1507/79/cb674d3c68be.jpg
http://s017.radikal.ru/i427/1507/37/a4af8613d395.jpg
http://s017.radikal.ru/i419/1507/39/db6ecacdd117.jpg
http://i023.radikal.ru/1507/fd/b2c27a467478.jpg
http://s017.radikal.ru/i408/1507/f8/56dc3a3dddb2.jpg
http://s011.radikal.ru/i315/1507/45/96effff8d147.jpg
http://s010.radikal.ru/i312/1507/96/6861fa1daae4.jpg
http://s016.radikal.ru/i336/1507/de/e9c9f7677a8a.jpg
http://s019.radikal.ru/i629/1507/1f/f675b31c6f07.jpg

Re: 5.0 TBI LO3 dyno
 

Math doesnt compute. Roughly 115 hp at 1700 rpms only gives 355 trq

Re: 5.0 TBI LO3 dyno
 

I'm not following. What are you trying to count?

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

I dont think that 460 trq value is possible given the hp. If dyno measures torque and back calculates hp, then it should be making more hp at that rpm. If those were projected flywheel numbers from wheel hp measurements it must be using incorrect conversion factors.

Just dont see that motor making diesel like torque off idle

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

I was pretty surprised by the figures myself, but the guys, that did the measurements are a racing team, they build 1000hp+ GT-Rs and tune them on this dyno, so they are very confident in what they are doing and in the results.
Here are the wheel measurements.

http://s017.radikal.ru/i440/1507/c9/03fa29da03bd.jpg

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

The torque is in newton/meters (Nm), in ft/lbs it is lower. Tossed me a curve at first too, then I remembered that other locales use different measurements. I've seen ones that list the power in kilo-watts.

RBob.

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Ahhh doh! I didnt realize this was in russia and in different units

Carry on! Curious to see what the 081 heads do

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

I did the same thing orr89.

yup, there is 746 watts per hp. or 1 hp =.746 kW

Re: 5.0 TBI LO3 dyno
 

No, its misleading. That first value is a "torque spike" from first hitting the throttle.

If you follow the rest of the graph and plot it back to the beginning along the same curve, you end up with about 430-440 nM, not 460.

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

With a stock to mild cam and dual plane intake they will LOSE under 4500 rpm and gain very slightly from 4,500 to 5,000-5,500. Dewey 316 and I both did testing with that result. Dewey's test was ported 416s.

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Will go back to the dyno after the install, and see the gain.
Cam is going to be
Duration (Int/Exh): 279/287
Valve Lift (Int/Exh): .447/.471

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Any other specs on that cam??? What was the seat to seat duration measure at? .004 or .006 or?? What is the 0.050" duration. What about the Intake centerline or LSA?

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Duration @ .050 (Int/Exh): 213/219
LSA/ICL: 112/108


Don't know the seat to seat duration.

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Keep up the good work, this is really cool!

That bird really 4WD ??? if so you need to share some pics and input!

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Where did you get the spoiler?
I want one

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Well of course not, it was a joke, just a 4wd dyno :lol:
I believe it would be impossible to make it 4wd on even close to stock chassis - just no room for a TC or a front axle. Or it would have to be a monster truck.

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Had to make one - no duck tails for firebirds unfortunately.

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Engine's done.
In the process of tuning right now.


http://s019.radikal.ru/i604/1508/60/477d76e476c9.jpg


http://s017.radikal.ru/i416/1508/dc/da468989344c.jpg


http://s019.radikal.ru/i620/1508/67/9f71ae69f806.jpg

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Ya figured... I want one super bad haha

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

I see the heads and intake manifolds ports have been cleaned up and gasket matched, how far did you go with the porting on the heads?, any work done to the bowls?

Looking forward to seeing the dyno after the tune, I been working on a similar350 TBI build myself

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Exactly, not many people notice :thumbsup:
Yes, ports have been gasket matched and cleaned as far as the cutter reached. Also both valves are larger than stock, pretty much the largest you can fit in these heads. I actually have an LS3 exhaust valve laying around and it is smaller than the ones I got. Needless to say everything under the valves has also been cleaned and ported.
You can also see how fat stock valves' necks are. You could get a little gain just by swapping those for thinner and polished ones.


http://s017.radikal.ru/i408/1507/f8/56dc3a3dddb2.jpg


http://s019.radikal.ru/i629/1507/14/08db3ecf20f8.jpg

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

looking good :thumbsup:

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Did the heads just bolt on?
Or did you head to do some adjustments to make them fit?

And what are the other bolt ons you have on the stock LO3?
I have bonestock LO3 TBI and i'm still figuring out what mods I'm going to do :P

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Heads are identical on the outside, so they are a direct fit.

During the dyno i had headers, ultimate tbi mods, 170F thermostat and a tune.

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Sounds like my future plans.

But what I know from the stock LO3 TBI is that it makes around 170HP.
Do those upgrades you have, only add the Torque?

Or do I miss something?

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

You are missing the fact that its a 30-year old engine. It should have been like 150 or 130 hp.

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

This thread left me wondering what was the final dyno results with these heads?

Re: 5.0 TBI LO3 dyno + 081 heads swap
 

Never actually got to that.
Ran into all kinds of problems with vacuum after the build - almost none.
Had to take the engine apart several times to recheck the seals, ports, valve tightness, etc. Even tried to change the cam - no luck.
Even Brian from TBI Chips had no more ideas.


So I just took the whole thing out and sold it.
Going with LS now.


I'm thinking the problem was in the valves, too big maybe, should have left them stock and just ported the heads.

Re: 5.0 TBI LO3 dyno
 

Re: 5.0 TBI LO3 dyno
 

We've already talked about ft/lbs vs. newton-meters.
Wild Guess: Torque converter multiplying torque below stall speed

But I could be wrong, I don't see any mention of which transmission this car has.

Re: 5.0 TBI LO3 dyno
 

It looks like Max hasn't been on the site since 12/2017. Perhaps he'll get an email notification that this thread was bumped.

Those are stock Rochester TBI units that have been modified. The lip around the bores is shaved off, the bores are enlarged, new larger throttle plates, throttle shaft is thinned, small button head screws are used to hold them on. Often an adjustable fuel pressure regulator is added at this time as well. If you search GM TBI on eBay, you will find vendors who sell parts and completed units, and their prices.

Re: 5.0 TBI LO3 dyno
 

Look up dctrumpet on ebay. Very nice TBI units built and ready to bolt on.

Re: 5.0 TBI LO3 dyno
 

Sorry, e-mail notifications did not reach me for a while.
TB is by SPR performance 46mm TBI with 5235206 350 injectors at stock 12psi fuel pressure.
If I remember correctly, around 300-400$ new.

Re: 5.0 TBI LO3 dyno
 

The SPRs are for sale on Ebay I think closer to 500 for whole assembly or 230ish for the base 46mm assembly.