AMGE

First off great looking exhaust upgrade!!!

Maybe the location of the x pipe is not optimal, maybe moving the x further back to a location where the two exhaust pipes are much further apart so you can better capitalize on the balancing effect the x in theory offers would help.

E55AMG99

Nice work Victor. A few random thoughts here.

IMO, the shape of the X-pipe might not be the most efficient. It looks like it is more of a common chamber where exhaust pulses are combined rather than two siamesed pipes where the pulses are allowed to flow in more equally spaced order.
Most of the x-pipes I've seen and used look like this. Maybe yours it too big?



H-pipes are not the answer for an already efficient exhaust system. More of a band-aid for bad design. Many tests have show very little exhaust cross-over in an H. Also, the gases will want to follow the path of least resistance and 90 degree bends are more restrictive than 45's!

Moving it as close as possible to the headers will maximize the x-pipe's effect which is to balance the V-8's out of balance exhaust pulses and create more even suction upstream for the next pulse.

Best of luck!

vrus

Not sure why the A/F is so lean.. The car did get a bit better on the way to the office this morning.. My trip home should put at 200km since upgrade and that was the magical # for the header swap, so we'll see what happens.

Thanks for the support! It will be AWESOME looking when I am done. Talking to someone about doing a Mandrel bend copy for me and then ceramic coating it.

I hear you John. I know it is SUPPOSED to be a great X-pipe.. It might be great if the tune were in line.. Maybe the cross section is just too open for my current power level?? Not sure. The only way I can find out is to remove it and put in a different style X-pipe in it's place and test it.

I also have to test whether moving it further forward or back makes a difference also.. This is gonna be a heck of a project to get perfect.

Can you by chance hook me up with a standard looking stainless X-pipe design like the one E55AMG99 posted on Page 2??


Thanks Albert. I was going to try and do a dyno to see what happens.. Kind of scared to wind it up to 155mph on the dyno though... A little torque loss I can understand, but there is significant difference.. Either that or the tires are spinning like crazy and I can't tell.

Thanks! I will have to play around with placement and do some dyno testing to come up with the OPTIMAL configuration for this.. Looks like the R&D on this project is going to be a handful..

What I am struggling with is trying to decide whether I should build for an almost stock car and make changes accordingly, or if I should build it assuming the ECU has been tweaked... That's my dilemna right now also.

Thanks! Much appreciated. It's nowhere close to done I would say at this point.. It's going to be some more hard work to get this right but I think the gains will be well worth it in the end.

Where can I get my hands on something like the 1st pic you posted? That looks like a nice stainless steel X-pipe.

Marcus Frost

I want to avoid bottlenecking because it can create various effects on exhaust flow. Sometimes minimal, sometimes significant. If you are looking for an unrestricted 600rwhp+ those headers are going to have to go for a good set of long tubes first. That's going to restrict you way more than 1/4" extra piping diameter. I prefer smoother exhaust flow than adding piping diameter that isn't truely the same size all the way through.

I have not run into cars choking at 600rwhp with true dual 2.75" exhaust systems (remember, that's technically ~300rwhp per bank of cylinders and 2.75" is plenty for 300rwhp). It's not quite that cut and dry but for all intents a purposes...

-m

jparch

Vic, if there is a particular design you want me may be able to fabricate it. I would put the x-pipe on with clamps ( band-type) and then move the position up or down to see if there are any differences. Once you find the optimum position then TIG everything up.

vrus

Something like what E55AMG99 posted above in the first pic.. If you have something in 3" stainless let me know.. I believe the version he posted above requires clamps anyways...

Grumpy666

Here's link to an article that will shed some light on the above. It is a good read on understanding fuel trim functions. The WOT O2 stuff is near the bottom.

http://www.c5forum.com/diy/ltft.php

Also in the article is another link to an Autotap config file to collect data pertinent to your situation, and an Excel template to analyze the resulting log file. I have not used the files, so I can't attest to their usefulness, and one of the parameters monitored is MAF flow, which you'll probably want to change for your speed density system.

Just curious, now that you've been driving around for a little while with the modded exhaust, have you noticed a change in interior resonance while cruising between 1500 and 2000 RPM?

Marcus Frost

Victor,

Some thoughts here, in no particular order:

Your exhaust guy does some mighty fine work! That looks OEM!

A leaner mixture isn't going to hurt power - leaner mixtures make more power than rich mixtures. I don't think that's the problem.

Is it possible that these cars use the secondary O2 sensors for more than just catalytic converter detection? There are cars that do that.

Have you looked at your timing #s pre/post exhaust upgrade?

I know for a fact our stock ECUs do require time to adjust themselves after significant upgrades. RENNTech has even said up to 250 miles. Have you done that many? I'd recommend doing some nice extended pulls late at night, like 10-150 or so to give the ECU as much data as it needs and get some datalogs going.

Get your car on the dyno WITH A WIDEBAND ASAP!

I don't think datalogging your O2 sensor values through OBDII is going to give you a clear enough picture given the really slow sampling rate we get through our OBDII ports. You need a dyno.

Your X-Pipe is in a perfect position and is could not possibly be affecting your situation in a negative manner. Leave it alone.

People have posted how an aftermarket software change is necessary when you do a full exhaust system (Kleemann recommends it) and it may just be our ECUs do not have that much self-adjustability.

Emissions standards outside of the **** Repulik of Kalifornia are MUCH, MUCH more lax on the rollers than they are for OEM production. Here in IL all they do is hookup to the OBDII port and look for a CEL. They don't even do sniffers anymore, unless they find a CEL.

We need Kleemann's or Evosport's input here on the characteristics of the ECU under these kinds of changes. None of us simply have the knowledge about these ECU capabilities like they do and all of our speculation could be answered with a single post from them.

-m

vrus

Grumpy,

That's too funny....

I did a search in google a few minutes after I typed my reply about the STFTs and guess what popped up??? Yup.. That article you just gave me the link for.. I already read through it, downloaded the files and am dying to get out of the office to do another log on the way home!

Thanks for looking out and for the tip! Mucho appreciated.

P.S-> As for resonance, noise... The darn thing is that it is QUIETER now than it was before.. It's hard to believe but it is. 0% resonance! How's that for a kicker. The X-pipe really is doing it's job in that sense.

I know the car is feeling better today than it did yesterday. I put only 100km on it so far since I got the exhaust done. Tonight should be another 100km and hopefully it will be even better. I've done so many 2nd gear, 3rd gear, and 4th gear blasts already hoping for exactly what you said.. the ECU to learn..

I will have to compare my timing #'s to my stock datalog.. I dont have many saved logs because i've had alot of trouble with the damn software... That's why I was hoping to compare against some of yours since you are pretty much stock.

I am seeing crazy things like -25degress of timing. I am also seeing 99.2% STFT.. I'll do another log tonight and see what the differences are.

Leaner mixtures SHOULD make more power, but for our cars with the excessive heat, I think it is a catch-22 with that one. Should make more power, but runs much hotter, ECU pulls timing, car goes slower..

I guess I will throw it on the dyno and do 4 or 5 nice pulls and see if it gets better.

Thanks for all the input guys!

Marcus Frost

That should probably be step #1

You'll have those tonight.

Remember, timing #s are conversed in AutoTap. -25 is actually +25, which is high, but within normal range. I will have to check my logs again.

That's why you have to check those timing #s - from what you posted it doesn't seem anything out of the ordinary.

That's the best way to find out. You'll get a good idea of your A/F as well as if your car has lost power on the dyno.

FWIW while I am surprised that the car isn't much louder, I'm also not surprised. Those stock mufflers are HUGE and they do 90% of the sound muffling.

-m

Evolution Marine

vrus - Try Burns Stainless - http://www.burnsstainless.com/ - they have them. - - Bob

vrus

I know they have a few different styles.. But, the pic I saw didn't look too impressive so I was looking elsewhere... It is my backup if I can't find anything else.

Thanks!

E55AMG99

Try Dr Gas

I'm starting to feel like an expectant father all over again waiting for the dyno numbers! Thanks victor!

45acp

I don't know what kind of datalogger you are running vrus, but look into these guys:
www.innovatemotorsports.com

Cory @ Kleemann

I've used Burns products in the past and I can't say enough about the quality of their work and product. everything they make is beautiful- nice enough to hang on your livingroom wall as decoration!

eclou

Vrus,

by further opening up the exhaust, you have increase the airflow through the motor even more than when you had just done the headers mod. Now you are probably well into the uncomfortably lean zone at peak tq. This is probably well outside the range that the ECU can adapt for the stock fuel maps, and even going outside the max capabilities of the stock injectors (at the stock fuel pressure) at peak rpm, especially if your datalogger is showing the duty cycles in excess of 99%. I don't want to beat a dead horse, but take caution on your dyno run. Shut it down if your AFR is in the 14's past 2500 rpms. I would also read your spark plugs before you dyno at all.

vrus

Ok guys.. Now we are getting somewhere!!! Last night I disconnected the battery in the car before I went to sleep. I was hoping by doing this the LTFT and STFT tables in the ECU would be cleared and it would re-adapt to the new components. Reading up yesterday night I found out that the STFT values follow the LTFT values.

This morning, the beast woke up as it's usual self! Much stronger pulling power today. I can still notice some torque loss (might still be because of the big X-pipe and not necessarily the 3" piping size) but the highway pulling power is very strong.

I can't say for certainty that it is faster or slower than it was before the exhaust change because all day yesterday I drove around an E55 SLUG, so this morning, anything would of felt faster to me. I will try to get some dyno pulls tonight to verify.

Then, I will put in a smaller X-pipe and redyno and see what happens.

Note: If you guys make any major changes to the car or just want to make sure you are getting the optimal settings whenever you do make a change, DISCONNECT THE BATTERY in your car overnight.

Thanks for the info! This is a nice wideband setup. I'm just using an OBDII datalogger right now.. I've been looking into the wideband stuff for a while but haven't committed to anything.

Hey Cory,

Thanks for the feedback. I know they make great products... The pic of the X-pipe just didn't look to impressive, but that might be where I am going to buy from.

I agree 100%. I am going to check my spark plugs.. I have been wanting to order a new set and re-gap them myself so I will probably pull them this weekend. Thanks for the feedback!

blackbenzz

I've heard disconnecting the battery may reset any ECU flash you had before, is this true?

Grumpy666

No, that is not true. Flash memory requires voltage to be erased. Data lost by disconnecting the battery would be limited to what was being stored in memory registers. These registers would then be loaded with default values when the ECU reboots from the flash memory.

E55AMG99

Like the grumpy devil said, it's not true. What data that get's erased is any of the parameter "learned" by the ECU over the course of (recent) history. Eventually, the engine should have figured out that certain parameters have changed but dropping the battery gets it done quicker!

eclou

battery disconnect usually wipes out the adaptation values the ECU has been storing for "learning" your driving habits. Most accurate OBD II dynos are done only after the adaptation values are cleared. Sometimes the battery disconnect can also clear fault codes (disconnect and touch positive cable to negative cable, neither connected to battery)

vrus

Hitting the rollers tomorrow night..

Will have video and HOPEFULLY datalog of the whole thing.

As Jeremy Clarkson would say: "Now we'll see what's what"..

vrus

*** UPDATE ***

Got home from the dyno... Got kind of what I was expecting.

I did about 6 pulls.. While I was there I decided I would test the stock intake snorkel and the S class snorkel. Hopefully to put this issue to bed.

I ran the first 3 pulls with the stock snorkel and the last 3 with the S class snorkel. I was also low 1qt of oil which probably hurt a little bit on the dyno.

Results:

The S Class snorkel on the car with the heat wrapping on it netted me 0 - 1rwhp difference, 3rwtq difference across all 3 pulls. My first 3 pulls were with a cooler motor and the stock snorkel. The last 3 pulls showed an improvement even though there was no cool down..

In order to be sure about this result, I will have to do some datalogs on the highway and compare the airflow rate (lb/min) between the 2.. At that point I'll know for sure which is better.. For now the S Class is staying on there all wrapped up.

I purposely ran back to back runs on the dyno to see if the power would drop off (to see if the EVO cooling upgrade was doing its job). It was consistent, so those 3rwtq numbers had to be because of the snorkel????? Anyways.. no big deal.

The important stuff:

Before I had the exhaust, I pulled 442rwhp, 497rwtq on my best pull (cool motor) and everything after that was heat soak and netted me 430rwhp, 497rwtq consistently.

Today on a hot motor (stuck in traffic for an hour before I got there) the best I could manage was 433rwhp, 497rwtq. Basically it was EXACTLY the same as my previous dyno before the exhaust.

Now, my datalogs are showing that the STFT are still 99.2% even after the battery disconnect. My car is definitely running a on the lean side.

Conclusions:

1) I can not say with certainty whether or not altering the exhaust on a stock ECU car with headers on it makes any difference. I think to make use of the better flow you have to get the ECU reprogrammed. I need a heck of alot more fuel and ignition advance in order to take advantage of the headers and exhaust upgrade.

2) Basically once you add Headers to a STOCK car, you are making the engine so much more efficient that the stock programming cant compensate enough to take full advantage of it so that is as far as you are going to get with stock programming.

Right now my A/F looks like this:

13.8:1 from 2,000RPM - 4,000RPM
12.5:1 from 4,100RPM - 5,000RPM
12-11.5:1 from 5,100RPM and UP

I know I can make alot more power if I just get some more fuel in there.. I found someone here who has access to programming equipment. We are going to read my ECU on Saturday and see if we can map some more fuel into it and also get rid of the VMAX.

Unfortunately in order for me to get past this magical HP barrier, I need to alter the stock programming. I wanted to know where the invisible wall was, and this is it.

The water/meth injection will probably help richen things up, so I am not sure in what order I will proceed.. Most likely I will test with an altered program in the ECU and see how much more power I can make.

I will also have to put in the smaller X-pipe and re-dyno.. Just to make sure I am not losing out because of the big cross section design of the one I have currently.

Here is a link to the video I shot (right-click Save As):

Note: It was a horrible, rainy day today, so the car is filthy..

http://69.17.158.20/vrus/video/E55_Dyno_1.wmv

Pic of the current dyno:

rflow306

Victor thanks for keeping us informed. Did you compare your timing numbers from before to make sure timing is not being pulled ?

vrus

This bloody datalogging software I have won't record properly on the dyno.. Maybe its because the ECU is in DYNO MODE?? not sure, but because of this reason I dont have anything to compare against.

I will be doing some logs on the highway and will have to compare against the logs Marcus sent me. His car is basically stock except for air filters so it will give me a good baseline to check against.

I am sure timing is being pulled.. It's way too lean < 4,000RPM and graph is very steppy now.. Will confirm once I have datalogs.

The work continues...