ESS VT2 600 @ 5.0 psi makes 543 RWHP on 91oct

[Longboarder]

Hey guys, so I returned to the EAS dyno today after installation of the MRF catless x pipe and Akra slip. A week ago with just the blower, I made 521 RWHP at 5.1 psi on 91 octane. Boost seemed low - especially since there was a VF car dyno'ing right after me making 7.9 psi. But power was good so I didn't think anything of it.

Last week's dyno thread here > http://www.m3post.com/forums/showthread.php?t=757829

So today, I made a bit more power. The dyno graph shows my best runs from last week and today. Strangely, I made less boost today. Peak boost was 4.99 psi. We got Roman on the phone and measured the pulley and verified that it is the correct pulley.

We even overlayed my dyno against many other supercharged cars previously dyno'd at EAS. In most cases, the cars made less power but more boost. I guess this is a good problem to have!

Anyway, I will be back to the dyno once again next week with some higher octane gas, which is how I will run at Shift-S3ctor. I need to get some practice in as traction is starting to become an issue in 2nd gear above 7,000 RPM!

Thanks to Tom and Steve at EAS for helping today.

[img]

[GOLFFRR]

awesome buddy! Can't wait to see your runs at shift!

[m33]

Dayumm dats stupid POWa Yo

[GIdriver]

Awesome!! Nice numbers!!

[1SICKM]

Nice !!

[pbonsalb]

You can make a little more or less boost just depending on atmospheric conditions. The blower spins at a fixed rpm, unlike a turbo, so it has zero adjustability. It can only compress what it gets, and what it gets is more or less dense depending on temperature and humidity.

The catless x-pipe reduces the restriction through the motor. This is why it adds power. On a boosted motor, boost is a measure of the restriction through the motor. Take the cork out of the backside and boost drops on a supercharged engine. Again, boost is fixed by the blower belt drive and has zero adjustability, unlike a turbo that will simply spool more or less fast to make the boost set by the wastegate.

Now raise the boost to ESS' specifications and you should see more power. However, I would first want to know why my installation made less boost than boost on identical kits on supposedly identical cars. There could be belt slip or a boost leak. Sometimes it is just a bad boost gauge, so I would want to check that as well against another reference.

[flipm3]

Thanks for sharing further documentation of your modding progress.

Once again proving that our stock full exhaust system pretty much sucks...hahaha

Enjoy the car and stay safe out there!

Originally Posted by pbonsalb

You can make a little more or less boost just depending on atmospheric conditions. The blower spins at a fixed rpm, unlike a turbo, so it has zero adjustability. It can only compress what it gets, and what it gets is more or less dense depending on temperature and humidity.

The catless x-pipe reduces the restriction through the motor. This is why it adds power. On a boosted motor, boost is a measure of the restriction through the motor. Take the cork out of the backside and boost drops on a supercharged engine. Again, boost is fixed by the blower belt drive and has zero adjustability, unlike a turbo that will simply spool more or less fast to make the boost set by the wastegate.

Now raise the boost to ESS' specifications and you should see more power. However, I would first want to know why my installation made less boost than boost on identical kits on supposedly identical cars. There could be belt slip or a boost leak. Sometimes it is just a bad boost gauge, so I would want to check that as well against another reference.

As always, great information! Couldn't have said it any better myself!

[Longboarder]

Originally Posted by img

Originally Posted by GOLFFRR

awesome buddy! Can't wait to see your runs at shift!

Originally Posted by m33

Dayumm dats stupid POWa Yo

Originally Posted by GIdriver

Awesome!! Nice numbers!!

Originally Posted by 1SICKM

Nice !!

Originally Posted by flipm3

Thanks for sharing further documentation of your modding progress.

Once again proving that our stock full exhaust system pretty much sucks...hahaha

Enjoy the car and stay safe out there!

Thanks guys. This is getting fun! I'm no where near done with the modding and it's already making good power. I was originally planning on maxing out somewhere at 575 RWHP with higher boost, meth, etc...and I think that's definitely achievable.

[Longboarder]

Originally Posted by pbonsalb

You can make a little more or less boost just depending on atmospheric conditions. The blower spins at a fixed rpm, unlike a turbo, so it has zero adjustability. It can only compress what it gets, and what it gets is more or less dense depending on temperature and humidity.

The catless x-pipe reduces the restriction through the motor. This is why it adds power. On a boosted motor, boost is a measure of the restriction through the motor. Take the cork out of the backside and boost drops on a supercharged engine. Again, boost is fixed by the blower belt drive and has zero adjustability, unlike a turbo that will simply spool more or less fast to make the boost set by the wastegate.

Now raise the boost to ESS' specifications and you should see more power. However, I would first want to know why my installation made less boost than boost on identical kits on supposedly identical cars. There could be belt slip or a boost leak. Sometimes it is just a bad boost gauge, so I would want to check that as well against another reference.

Yesterday at EAS we double-checked for any boost leaks (none), blower belt slippage (none out of the ordinary) and pulley (correct one for 600 kit). Boost was also constant (4.9 to 5.1 psi) from my run a week ago where it was around 65 degrees compared with 80 yesterday (I made a little less boost yesterday).

EAS is also measuring boost @ the vacuum line like they do with all other supercharged M3's. They have dyno'd quite a few and so Steve@EAS was overlaying my dyno with others. Most others with the ESS 600 or VF 620 were 6-8 psi. Strangely, I made more power than most of these higher boost cars, which is why I'm not overly concerned. I have no idea why, but perhaps my car is just flowing better.

[Longboarder]

Here's my air/fuel ratio and boost. Ignore the spike at the end upon throttle closure. Not even making 5psi peak. Feels great...no boost leaks...correct pulley...hmmm.......

EAS has a mechanical boost guage and so I'm going to ask them to hook it up on the next dyno session to verify.

[DLSJ5]

Originally Posted by pbonsalb

You can make a little more or less boost just depending on atmospheric conditions. The blower spins at a fixed rpm, unlike a turbo, so it has zero adjustability. It can only compress what it gets, and what it gets is more or less dense depending on temperature and humidity.

The catless x-pipe reduces the restriction through the motor. This is why it adds power. On a boosted motor, boost is a measure of the restriction through the motor. Take the cork out of the backside and boost drops on a supercharged engine. Again, boost is fixed by the blower belt drive and has zero adjustability, unlike a turbo that will simply spool more or less fast to make the boost set by the wastegate.

Now raise the boost to ESS' specifications and you should see more power. However, I would first want to know why my installation made less boost than boost on identical kits on supposedly identical cars. There could be belt slip or a boost leak. Sometimes it is just a bad boost gauge, so I would want to check that as well against another reference.

Good post, and I agree your posts are very informative, smart, realistic and thought out.

Joe at Trinity did not see his boost go lower when he added a catless Xpipe vs. the stock cats, in fact I think his boost increased almost 1 psi ~6.8 to ~7.8psi when he went catless, so I'm not sure that theory always applies, although the dyno's were not done on the same day, so conditions could be a factor as well. FWIW I didn't see a change either when I went catless.


Good work Adam, why not go VT625 for the event?

[Longboarder]

Originally Posted by DLSJ5

Good work Adam, why not go VT625 for the event?

I inquired about a 625 pulley upgrade and it's doable with my kit since I have the white/gray injectors, but I'm not sure I want to void my ESS warranty just yet. I want to run it hard at the Airstrip and then a track event to make sure everything is good first.

[CarbonFoot]

Originally Posted by pbonsalb

On a boosted motor, boost is a measure of the restriction through the motor. Take the cork out of the backside and boost drops on a supercharged engine.

Can you expand on this statement? I don't see a strong correlation between boost pressure and exhaust restriction. While, of course, a high flowing intake and exhaust should be well matched to produce good power, I see them as separate functions.

As I see it; when boost is created, it pressurizes against a closed exhaust valve during the intake stroke. During the exhaust stroke the intake valves remain closed until just past TDC. I can't imagine a lot of blow-by is occurring in the cylinders under boost, where the supercharger is pressurizing against a restrictive exhaust. Exhaust pressure is generated by the compressive force of the exhaust stroke and not the intake system.

That being said, I don't see how uncorking the exhaust will lower boost.

Please correct me if I'm wrong as I don't know much about actions of vanos and the resultant effects it may have on this.

[tryingtobebest]

This is sick!)))

[flipm3]

If you don't mind, could you post SAE and Conditions as well? Great documentation thus from in a step-wise fashion!

Hopefully you got a chance to enjoy all the power this weekend! Keep us posted on your next stage!

[biglare]

Congrats on the powa!

Time to invest in some sticky rubber!

[the infamous...]

great #s, enjoy!

[pbonsalb]

Originally Posted by CarbonFoot

Can you expand on this statement? I don't see a strong correlation between boost pressure and exhaust restriction. While, of course, a high flowing intake and exhaust should be well matched to produce good power, I see them as separate functions.

As I see it; when boost is created, it pressurizes against a closed exhaust valve during the intake stroke. During the exhaust stroke the intake valves remain closed until just past TDC. I can't imagine a lot of blow-by is occurring in the cylinders under boost, where the supercharger is pressurizing against a restrictive exhaust. Exhaust pressure is generated by the compressive force of the exhaust stroke and not the intake system.

That being said, I don't see how uncorking the exhaust will lower boost.

Please correct me if I'm wrong as I don't know much about actions of vanos and the resultant effects it may have on this.

The improved exhaust in effect increases engine VE. If the engine can pass more air, it passes more of what the blower feeds it. The blower drive is fixed by the pulley so there is zero compensation. The engine now can use more air but the blower won't provide it. Not as much air is backing up in the intake against the blower driving it, so boost drops.

There is overlap, especially on an 8000 rpm motor, even with dual vanos. But I am not sure that is the full explanation for the effect. Let's say you plop a fully ported big valve head on there that flows 15% more air, and the valves work to the theoretical perfection you propose and the exhaust or intake are either entirely open or entirely closed but never both open at the same time. The engine will process more of what the blower sends to it. To maintain the same boost, you would have to increase blower output by 15%. The boost is measured in the intake, and the engine just gulped up 15% more of what was in the intake so there is less pressure there.

[nerwyll@trinityautosport]

good meeting you =)

[joe@trinityautosport]

Very nice! How do you like the sound of the exhaust now?

[positiveions]

Numbers are looking good.
Do us a big favor, don't embarrass us out there . Keep it cool, and drive safe.