Been wanting to baseline the 5.8 I built.

Came across these guys at Crusing the Coast Thursday before Nate washed the whole thing out.

Pass Time Performance of Bogue Chitto, MS (Thanks TJ)

$60 for 2 pulls. The price was right & worth every dime.


It was blast.

No shake, no smoke, no rattle.

They seemed very impressed with my little truck & its Windsor.

193.8 HP, 267.1 ft lbs Tq.

An "indicated" 125mph

It pegged the speedo at about 4200 RPM

(Thanks Thomas for the camera work.)

 

What a great opportunity!

I followed your build thread closely. Based off that pull what do you think your making at the crank?

 

Well, part of my & TJ's discussion was just how much got eaten up before the wheels.

Horsepower sucking E4, 2-piece, mile long drive shaft with carrier bearing, he figured at least 30% & possibly as much as 35%.

So I sat down with a calculator & came up with 3 (5) possible sets of numbers:

Edits in bold,

If 241 HP at FW & 20% loss, for 48.2=192.8 or a gain of 31 HP over stock 210... or

257 HP at FW & 25% loss, for 64.25= 192.75 or a gain of 47 HP over stock.

280HP @ 30% = 196 RW
290HP @ 35% = 188.5 RW
300HP @ 35% = 195 RW

So I'd have to guess maybe about 293-295.

I'd scan the print out, but they had to be about out of ink. Barely visible. (going to e-mail & ask if I can get better copy)

Started the runs at 3000-3100 & hit max tq @ 3650, HP peaked @ 4250!

Then it just hit the wall & fell flat at 4850.

Everybody nearby kept muttering "needs more fuel".

EDIT

Guessimated flywheel torque numbers based on 20, 25, 30 & 35 percent drive train loss:

411 FW Tq x 35%= 143.85, so 411-143.85= 267.2 or 86 ft lbs increase

382 FW Tq x 30%= 114.6, so 382-114.6=267.4 or 57 ft lbs increase

356 FW Tq x 25%= 89, so 356-89=267. or 31 ft lbs increase

334 FW Tq x 20%= 66.8, so 334-66.8=267.2 or a WHOPPING 9 ft lbs increase.

Pick your percentage of drive-train loss.

 

Nice. That's pretty dang good. And on the top end did it run out of fuel or intake manifold lol.

 

Do you have a tuner on that truck?

 

Original cap repaired SD PCM. Zero tuning.

Injectors are all rehabbed (by me) original 4-hole orange Bosch (save for 2)

I've got a BBK gauge on the fuel rail that gets into about 43-44 lbs range when the vac line is pulled.

I am a little concerned that my pressure is leaking down to zero overnight lately where it would normally hold some pressure for days.

 

Well for what it's worth the instructions on my AEM regulator say that it will SLOWLY bleed pressure.

I've heard that a test is to remove the fuel rail with injectors attached and prime the system to check for leaking injectors, although wouldn't be hard to do on a bench with a compressor and rubber nipple.

Ever consider a MAF conversion?

 

Here's the test rig I mocked up after "rebuilding" injectors.



This was actually before the rebuild & they didn't even have a couple hundred miles on them.

I killed the O rings with the cleaner I used. Re-did them with Felpro rings.

Here's the (partial shown) 94 mass air harness I'll be editing this winter. I've got a ECU, (MUT1) meter, air box & TB tubes.

 

Nice numbers David. Based on a few previous dyno posts I would say a good 300 HP at the crank.

Did you happen to notice what the fuel pressure was when the power dropped at ~4850?

I recall the factory computer shuts off spark around that RPM??? Could be wrong....

 

Thanks.

No, sadly the gauge is rail mounted.

I would so love to know the details on truck fueling/ignition strategies.

 

With a locking convertor and 8.8 axle, you're likely not losing more than 20-25% through the drive train (the taurus fan helps too) but that's not to take away from the pull...solid numbers for factory cam and stock gt40 castings. I'd consider a wideband if you haven't already.

 

Little bit better than stock cam, but not a lot:

35-512-8 - Xtreme Energy? Computer Controlled Hydraulic Roller Camshafts (For 1992-02 Magnum Engines WITH 1.6:1 ROCKERS)

 

Good to know. But um, I was hoping for some more. Is the consensus that this is about the limit of speed density on our 5.8s?

Numbers are less important to me really. The questions I have are, how does it feel from the seat compared to before? And does it fill your needs as stated in the build thread?

 

Well of course I'd like to have gotten more.

Would have liked to have had a solid 200+ @ RW right off the bat.

As far as seat of the pants goes, it runs like a scalded dog compared to the original un-modified truck as well as each modified stage.

I'm pretty happy with my junkyard parts & an engine that I built from the crankshaft out.

And it has plenty of room to grow, but I'm not going to go wild.

As far as SD limits go, I got nothing.

 

About stock SD: There are only a few of areas where you have room to grow, in your particular case, and still be able to run in stock SD tuning. Ported gt40s, compression bump, long tubes, cam with a little more duration (that really is a near stock replacement cam). There really isn't a single number that can be "supported" by SD, but the further you go from stock, the less optimal it is.

Tweecer supports speed density tuning, and there are options to ghetto tune speed density with adjustable fuel press regulators and computer swaps, but these are ways to make a setup less "Less than optimal".

Hp doesn't just fall from the sky, ~265 hp is not bad considering that you have simple, mild mods. 50+ Hp over stock is not too shab.

Tweecer might be what you need, since you seem to enjoy tinkering and understanding what's going on with your truck. I'm running stock SD with the 97 in my sig, with 50 lbs of fuel pressure it's safe, but I'm going to get the tweecer when I get time, even on 93 octane I'm limited to ~5-6* base timing.

On that note, what's your base timing?