Dyno results - stock, stock w/ just piggies, and now piggies, exhaust, and tune

B6/7 S4/RS4
#1

Just figured I would share these, since I finally bothered to make some more runs. I made a few runs Saturday and discovered that I was missing MASSIVE power up top. Given the power loss started around 5,000rpm, I figured it must be the intake flap. Sure enough, it’s very tough to move by hand and was stuck in the low rpm position, but it moves (and stays where I put it no matter what). So I took her out again Sunday morning to make some runs with it in the high rpm position, to compare. Surprisingly, the loss in the low end was small, and honestly I didn’t feel a difference at all in the seat of the pants. But up top, I definitely felt and heard the difference with the flaps in high rpm position. Makes me wonder if removing the flaps altogether would really be that bad.

Anyway, here’s the graph:

http://a2.sphotos.ak.fbcdn.net/hphotos-ak-ash4/241936_10101140165665711_1483995129_o.jpg

Blue = stock (ignore torque spikes - RPM pickup was not good, as I was learning the GTechRR)
Green = piggies only, no other mods
Red = piggies, Magnaflow exhaust, JHM tune, intake flap stuck in low rpm position
Black = piggies, Magnaflow exhaust, JHM tune, intake flap stuck in high rpm position

Notes

  • Car is a 2004 S4 Sedan 6MT. Bought with 56k miles, now has 65.8k miles.
  • The Green line was performed at about 37F ambient temperature, while the Red and Black were at 74f and 71*f, respectively. All were created very very close to sea level and in dry weather.
  • I’m sure everyone is aware that the GTechRR is pretty precise, but reads notoriously low.
  • I also have trouble getting the tach reading perfectly; the Red and Black lines were run right into the rev limiter to see what would happen, so that should be pretty indicative of around 7200rpm or so in reality, not 6700rpm.
  • If you dyno a GTechRR (in second gear) back to back with a DynoJet 248c, you’ll find that it reads about 20% lower very consistently. At least that has been my experience, as I have done this several times with other vehicles. This would put me very nearly at 300whp, but no cigar. Not surprising to me, since this car laid down 269whp when I first bought, bone stock.
  • I also did not average multiple runs. For those of you not running intake manifold spacers, I’m sure you’ve heard about heat soak. Every run I make is at least 3-5hp less than the last, no matter what the ground or wind is doing. The only way to fix it is to drive for a few miles without stopping, then quickly stop and make the run. Since this is a GTech, this isn’t always possible, as traffic gets in the way. So I find a flat road (flat as confirmed by the G-sensors when stationary, as they will show you what is and isn’t flat) and go with the best result after a few passes back and forth, trying to give it some cooling time in between.

Conclusions:
(considering a healthy engine as a proper mix of the Red and Black lines, with changeover at ~4700rpm):

  • Piggies made the ONLY difference below 4,400rpm - the exhaust and even the stupendous JHM tune gained nothing, though some small gain probably would have showed had I made the Green run at the same temp as the new Red and Black runs. Obviously, above that, the tune is making gigantic power over stock, with the exhaust probably playing a significantly smaller part than the tune.
  • The crossover of the Red and Black lines shows where the ideal flap changeover point is - right about 4,400rpm. The tach signal is a little off on this graph, so 4,400rpm indicated is more like ~4,600-4,800rpm in reality. I seem to recall Jay&JHM stating that their crossover is at 4,700rpm, so they’re pretty much tits, as expected.
  • The peak power engine speed hasn’t really changed at all with these mods, and neither has the torque peak engine speed. The numbers next to the graph say it has, but the torque in that area is basically flat, so minor undulations cause the absolute peak number to be at a different speed.
  • Gains over stock are about 20ftlb from 2,500rpm to 3,500rpm, peak gain of 30ftlb at 5,000rpm, and still 20ft*lb from 6,000rpm up. Overall, this is a much, much quicker car that plainly makes a big difference in area under the curve. For the limited money spent, this is definitely a big win. Peak gain of about 30whp over stock, and that’s still with the GTechRR’s severely deflated numbers.
    -piggies = free (DIY)
    -exhaust = $675 I think, shipped
    -tune = $560 or so shipped both ways
    -total = $1,235
  • The losses in the low end from having the flaps in high rpm position (Black line) were really not bad at all compared to the low rpm position (Red line). I thought I had read somewhere that JHM had tried leaving the flaps in high rpm position and lost 55ftlb. These results make me want to see what happens if I totally remove the flaps and somehow close off the low rpm runners. They look like a massive obstruction to the high rpm runners when they’re in low rpm position, so I’m rather sure I would see even bigger gains in the top end with them completely removed. Perhaps JHM saw a loss of 55ftlb when removing the flaps completely because both sets of runners were open? It would be an interesting test. If I ever find myself with a spare intake manifold, I’ll be keen to test block off the low rpm runners and removing the flaps completely. I know, I’d need a block-off plate for the front of the manifold, yada yada.

I’m not planning on spending any real money on her any time soon in the name of performance, though I do have a couple cheap projects planned and some minor maintenance/repairs to work on (including freeing up the flap mechanism). I do wonder, however, how much torque the stock B6 clutch can hold. I don’t launch the car, as I don’t see the point, but at some point the torque it can hold will be outrun by the torque the engine can produce, and the clutch disc will just become a polishing wheel. I’d love to know about where that point is. Rephrased, I’d love to know if my next performance purchase can be catless downpipes, or if it needs to be a clutch first.

#2

you’ll be fine with the stock clutch, I had a stock one at 300wtq and it held fine except on launches with sticky tires

itd be interesting to see if the S6/8 intake manifold could be adapted to the S4, its a much better design. When in the long runner mode the two flaps sit on top of each other sealing the top runner, then when it switches both pivot down to seal against the long runners. They stay out of the way of the TB and actually seal the long runners vs the S4 manifold flap just hanging out in the way.

#3

My question was really whether or not the stock clutch could deal with 320 or 330 ftlb. Clearly it is dealing with my almost 300ftlb right now. I have had these mods for a while now.

If you happen to know anyone with a spare S6/8 manifold, I’d be happy to be the guinea pig. I have a feeling that the spacing of the runners will more or less mirror the bore spacing, and therefore will make it not really worth the effort.

I keep toying with the idea in my mind of taking the parts of the S4 cast manifold and using them to make molds for a plastic replacement, though, which would probably be superb. Especially if the losses from losing the dual-plane nature are as small as my dyno’s suggest. Just taper the ports on the molds so they line up with the factory heads, fill in the flap shaft appurtenances, delete SAI while we’re in there, and clean up the factory runner inlets . . . Still too much to invest I think. For now it will remain mental masturbation I guess.

#4

Email this guy:

http://atlanta.craigslist.org/nat/pts/3001570264.html

He has had those S8 for part-out for a long time now. Although I think he knows what stuff is worth so I doubt you’ll get amazing deals or anything. I asked him about the brake calipers, rotors, and carriers since the D2 S8’s had like 6 or 8 pot Brembos and he basically asked a standard price ($700-900 I think)

#5

All looked good I didn’t get a chance to fully read the post but I can tell you The S8 or S6 intake manifold wont work for you. There is clearance issues. I put one on my car but it took lots of hacking and modifying the brackets with a new lever system.

#6

Squiddy take your torque curve and multiply it by 1.2

Then plot it in excel or something along with calculated HP. You’ll see that the new HP curve is dramatically steeper.

#7

That is actually what I did. 293ftlb and 296.6hp. That’s pretty damned good in my book, though admittedly the car was strong stock with 269hp bone stock. The avg correction is 19.9% by my figures from GTechRR to DynoJet/GTechPro, which were virtually identical. Also shows much bigger gains, of course. But it still shows that with the flaps installed and stuck in high rpm position, I’m only losing 25ftlb of torque in the low end. From the seat of the pants, it’s not enough to stop me from thinking that maybe an RS6 intake manifold might be a good idea. I’ve been doing some digging the past few days on manifold options. Not much out there, and the S6/S8 intake manifold does look good, but if I could dig up a few more ponies than that and still save the $1k for the JHM intake manifold I would be happy (since I absolutely will not be spending $1k on the car right now, that is not an option).

I know JHM said they lost 55ft*lb by disabling the flap system, but I wonder if they completely removed the flap arm and lost that. In which case the RS6 manifold would be a possible solution, as would removing the flap system AND blocking off the short runners entirely. Perhaps they lost a lot more because air was going through both sets of runners? I will be talking to them this week to see what they already know and save me the hassle of repeating it.

#8

The testing done on the intake was quite extensive… 9 tests. were done

start test for flow

test one was short runners locked
test two long runners were locked
test three short runners were locked and then blocked to assure no seepage of any air
test four long runners were locked and then blocked to assure no seepage of any air
test five different style flap design smoke test for seepage on seal up in both long and short runners
test six chamber molding test for flow
test seven test spring rate
test eight test bare
test nine new flap with molded runners different spring rate

I did testing with a Rs6 intake and a S8 and a A6 intake. The single stage such as the Rs6 TT intake is IMO a waste. I have some of the results Ill see if I can post pictures. The multi stage intake is a very large component in helping the car make over all better power. In the JHM tuning the intake flaps are opened at a different rate then stock. This also helps the car make more power.

#9

are you in the end basically saying that the flaps are good to keep in the car?

#10

He is not talking about an rs4. This is an s4 thread.

#11

I have no doubt that JHM did their homework; they always have in everything else I’ve seen. My results don’t seem to show much of a loss for not having low-rpm flap position, though, hence I’m wondering. If you could post the images, that would be great. If not, send me an email and I’d love to take a look for myself. Knowledge is power.

#12

I’m referring to the shape of the curve, not the peak numbers or multiplying to come up with something to compare to a dyno. It’s a mathematical thing…the steepness will be exacerbated (or suppressed) on the hp curve depending on the levels/losses factored in. i.e. in the dyno world a ‘low reading’ dyno shows a much flatter curve than a ‘high reading’ dyno. Not equal across the board and just raised up a bit…the shape changes. That’s why I think you’re seeing such a flatness, not necessarily a problem with the intake.

#13

Okay, let’s go to ratio then, where the numbers themselves are irrelevant. By the chart I posted, my peak loss in high rpm position is about 15ftlb, and the peak torque posted in low rpm position is 235ftlb. So my peak loss was 6.4%. JHM said they lost 55ft*lb by disabling the flap system, which is, I’m pretty sure, not 6.4% of the torque they made with the flaps working properly. Just wondering what they did differently than I did.

#14

Are you sure your flaps don’t work?

#15

Absolutely. You can see the difference in the red and black lines in my graph showing that they are indeed different. I can also see the actuator not moving with the car running - it stays exactly where I put it, whether I put it horizontal, vertical, or anywhere in between. And it’s TOUGH to move it at all.

Anyway, I finally talked to them over the phone today. Their large loss number was on a car that had their headers and some other stuff, and they only removed the vacuum line from the actuator, leaving the spring to hold it in the high rpm position (didn’t remove flaps entirely). So maybe that’s the big kicker? Maybe the headers demand a lot more flow down low? I’d believe that. We already know the headers are a massive torque boost for the low end. They were also pretty mums about what else they tried while developing their manifold work.

They also said somebody ran their B7S4 with their blower kit on a stock clutch, and it held okay so long as they didn’t try to launch it. Wow; the stock clutch isn’t getting enough credit. I’m sure it wouldn’t hold up to much abuse that way, but the fact that it can even clamp that much torque in the first place just boggles my mind. It’s a tiny disc to be able to do even that. That makes me think that my stock clutch will happily hold up to general/spirited street driving if I go pursue downpipes and/or intake manifold next, rather than getting a better clutch first. B6 is definitely weaker than B7, but it’s not that massive a difference - it’s only 400lb in clamp load, which is I think 20% (stocker is 2 kip?). Any of the above is still a ways off, but I like to plan things out so I don’t break things or waste money.

#16

I launched my b7 over a million times with no problems over 65000 miles on the stock clutch

:slight_smile:

well one hundred passes at the strip…another couple hundred full bore launches on my own including a ton of testing for jhm launch assist

#17

WEll they have a header car so each component will be effected perportionally. So you can look and say the more power you make the more something Like the flaps will effect. Also you were sayiung that you didn’t see a gain at a point down low even with the JHM tune. I however saw a larger gain down low with the JHM tunbe then you did. I had catless set up and then again with the headers when I installed them.

When you think about it. I would attest this more to the hp level and its % per that reange…

Look at it this way. The JHM supercharger. They use a restricted intake inlet on there supercharger kits to help keep the power down to keep the motors safe just like the older Vortech LS1 kits. Now if you have a restricted inlet on a stock car your hp loss isn’t going to be all that big. Have a restriction on a superchaer car and you have the 50whp reduction in power that JHM acheved just by putting the restriction.

IF you ask me. Your piggies the temps are part of what might be keeping the numbers donw. I would wager that if you did this in the coler weather or with a better Dp set the losses might be more in line

#18

Quite true. I would imagine that piggies are probably holding me back. Trust me; some real downpipes are next in in the queue. As I recall, the piggies don’t quite eliminate all of the ignition pulling on the stock map (based on the datalogging posted a good while back by somebody), so I’m sure there’s some room for some nice gains with real downpipes. And I will be retesting this winter on one of the colder days, to try to make a more stout comparison against the numbers with just piggies. I certainly won’t have the money to do anything else to her before winter, unfortunately.

Sak - wish I had a B7 clutch . . .

#19

So how much better are some decent straight through 2.5" downpipes (no cats) than piggies with all 4 cats gutted?

#20

I didn’t see a monstrous change but some people do

I trapped only about 1 mph better with downpipes vs piggies but some people pick up 2-4 mph.

Piggies are excellent.