Sunday Dyno Session

[Jarrod]

Well, you're shooting down BBB's w/removed air horns as a worthless modification and I'm stating you're using and did use them in a WRONG application to determine that. Those who have them do install them with other usual bolt ons as you say, but a MAF, tune, and BBB's is not a combination known for usual bolt ons. You're probably the first one to ever do that combo. Most already have a y-pipe, catback, ported/extrude honed runners, head work, udp's, lw flywheel, cai, and ect.

FWIW on the ATX dyno, I've seen stock ATX's put down what you put down stock. You might find a graph in the dyno section.

But.. this does help prioritize mods for newer forum members. It will keep people from making the BBBs one of their first mods. I honestly really appreciate the information, and am glad that I kept the horns from the spare intake I have.

I don't know how much access Sal has to a dyno, but I really appreciate this type of info. If he were to keep going, and added a y-pipe and ported intake to the mix, and report his results then, it'd be very beneficial to the entire SHO community. For now, my butterflies are staying stock with the air horns...

 

[SHO Dude]

Here's what I got out of a stock '93 ATX. I ran it with the factory 55mm MAF, then a 70mm MAF and finally a 80mm MAF. The car has a K&N air filter in the box, one of our FPS High Flow y-pipes with cats and a Dynomax exhaust system.




With the stk MAF, the car was 12.0:1 at the hit. But leaning out the mix only made a couple of hp. The 70mm MAF was a little lean to begin with and fattening up the mix made a couple of hp. The 80mm MAF was the leanest of them all. It did make the most power, but at the expense of AF mixture. Fattening up the mix made it a lot more comfortable.

The spikes in the tq curve are due to a flakey pickup.

 

[Power Surge]

STILL waiting to see the graph for the bone stock ATX car that made more than 190 whp.

 

[TYSHO]

STILL waiting to see the graph for the bone stock ATX car that made more than 190 whp.

I'm still looking to see where you got that someone said a bone stock ATX dyno'd more than 190whp...I can't seem to find it anywhere in this thread. Your stock dyno showed 178whp and it was said an ATX has done that or better. It's not like any of that is important, I'm sure the majority of us are more interested in other gains from modifications you put on the car from now. What's next?

 

[Power Surge]

I'm still looking to see where you got that someone said a bone stock ATX dyno'd more than 190whp...I can't seem to find it anywhere in this thread. Your stock dyno showed 178whp and it was said an ATX has done that or better. It's not like any of that is important, I'm sure the majority of us are more interested in other gains from modifications you put on the car from now. What's next?

Here you go....

those numbers are less that my stock ATX last time it was on the dyno at 215K

This is the SECOND thread of me posting dyno graphs that somedude_001 has jumped in and touted his stock 215k mile ATX has made more power than my car. There's no reason for that other than to be an ass. I just want to see the dyno sheets for this car, I don't think that's too much to ask.

 

[Yamaha V6]

Here's my not-stock 95 ATX:

and my run this week with the current 91:
Green: '84 Porsche 911
Red: '91 SHO (see dyno section for details)
Blue: former '91 sc'd SHO

 

[TYSHO]

Here you go....

This is the SECOND thread of me posting dyno graphs that somedude_001 has jumped in and touted his stock 215k mile ATX has made more power than my car. There's no reason for that other than to be an ass. I just want to see the dyno sheets for this car, I don't think that's too much to ask.

Ahh, well we all know a stock ATX, regardless of dyno power, is still slower than an MTX. The reason I said something about an ATX dyno was because I thought your SHO could do better than the 178whp to begin with, suggesting it might've needed some maintenance, that's all. I wasn't trying to put down you or your SHO, just so you know.

 

[shomesomesho]

Now here are some interesting things I found, while tuning...

The car made best power at 12.8 A/F across the board. Pretty average, but some NA cars like to be closer to 13.0. My car didn't gain anything at that point. Increased mid range spark added some good power. And an extra few degrees up top, also netted some nice power additions to the graph.

Thanks for sharing this. I changed the A/F to 12.8 (formerly 13.1) on my car and was about 0.5 to 1 sec faster on the autocross course this weekend. I also have timing advanced mid and upper rpms at WOT.

 

[SHObill]

Well, you're shooting down BBB's w/removed air horns as a worthless modification

All by them selves it is! & a lot of people do it! Without gasket matching & porting the heads & secondary runner to head, & extensive porting of the secondary runner to the BBB's, & then you leave the horns out you will have NO gain across the power band & you are wasting your $$$ & time !! IMO modified horns =larger dia. & shorter- will be the only way to see some gain across the band as you are compleating the intake path. BUT a motor is an air pump, what may enter has to come out just as effectively. So exhaust mods must be made to see true potential.

[/QUOTE] -- MAF,catback, ported/extrude honed runners, head work, udp's, lw flywheel, cai, and ect.[/QUOTE]
NONE of those are power mods!

 

[TYSHO]

Without gasket matching & porting the heads & secondary runner to head, & extensive porting of the secondary runner to the BBB's, & then you leave the horns out you will have NO gain across the power band & you are wasting your $$$ & time !!

So exhaust mods must be made to see true potential.

-- MAF,catback, ported/extrude honed runners, head work, udp's, lw flywheel, cai, and ect.

NONE of those are power mods!

Bill, you just ruined your own theory!

When I listed head work, I meant the whole 9 yards and then some, like all the things I underlined when quoting you. Then you said you need exhaust to see true potential, a catback is part of an exhaust and "and ect." is meant for other things as well, depending if someone wants to use a catless or catted y-pipe, or possibly headers and/or dual exhaust. If none of the parts I listed are power mods, people wouldn't be installing them for gains.

 

[SHO Dude]

Here's a dyno plot of a car I did last week. Bone stock '93 enigne. We did our ATX Y-pipe and a full Dynomax exhause after a complete 60K.



Nice and smooth all the way to fuel shut off. Had the AFR dead on 12.9:1.

 

[Lance Cheney]

I really didn't let off early, I was losing the dyno tach signal over 6500. If I put the lower axis on mph instead of rpms, you would see the rest of the graph, but it really wouldn't tell anything.

If you look at the graph, power was on the downslope, so really going another 500 rpms would not have netted any higher numbers.

Your big gains are in the 6000+ RPM range -- if you have data about 6500 RPM on another run with the new setup then you can use it to have a better idea of where your shift point should be. With your old setup, power was so far down on the top end that your shift point would be in the 6500-6800 RPM range, depenidng on gear. With the new one it looks like you likely gained at least 500 RPM of useful power band, which we need with the crappy gearing on the car. Since that 2-3 shift will drop you from 7000 RPM down to 4600, on the original configuration you'd be best off shifting at around 6700 RPM (where you let off) -- 150whp at 6800 RPM, and about 150whp at the shift-in point (4400 RPM). Now do that on the new motor... I'd estimate you would be at ~175whp at 6700 RPM, but you're still getting the same 150whp when you get into 3rd gear, so you're fully using the huge advantage you gain from having so much more power on the top end... You can now shift at ~7300 RPM, probably with 160-165whp still, and shifting in at a similar point. You've gained several hp*s of usable work energy, and there is less of the 'climbing up the HP curve' business that you usually get on a rev-limited engine (like my stupid CSVT, where peak power is at 6600 RPM and the rev-limiter is at 6800 RPM). Peak power on my 3.2L is at 6800 RPM but the power only drops about 10 hp from 6800 RPM to 8000 RPM...

And you're right -- when you remove the air horns you change the upper resonance point, and that's part of where that 20hp gain at 6300 RPM comes from -- that gain would have likely been higher as the RPMs went up. Having a set of half-length, larger-diameter air horns would probably be a good fit for a car like this. A high-RPM cammed car build would definitely leave them out.

The cars I've seen with the 73mm C&L also show a significant variation vs. the factory MAF. I'd never recommend one as a drop-in replacement without a Tweecer. I also found ONE (1) HP when swapping from paper to K&N filter on the factory airbox. That could just be run-to-run variation, but in general changing anything other than MAF (which netted me 7whp) doesn't seem to make much difference.



Good results!

-Lance