So my MCS is currently at a local shop (RevLine Motors in Kansas City) getting a custom turbo back exhaust built for it. Before doing so, I wanted to get a baseline dyno of my car while it was still bone stock. Now, I'm jumping the gun a little bit because I don't have copies of the dyno graphs yet, but I just got off of the phone with him and thought I'd go ahead and share the beginnings of the journey:

Stock R56 MCS: 177whp / 192wtq

The dyno was done in 3rd gear with Sport Mode on. I need to check on things like SAE correction, weather, and type of dyno that I know a lot of you all will want to know and I'll try to get that as soon as I can. The guys at the shop told me that their dyno is known as the "Heartbreaker" because it dynoes so low! This was the reason I was exceptionally surprised to see the above numbers.

The car is now being torn apart and my TBE is being assembled (had to order the turbo-downpipe flange after taking exhaust apart b/c we didn't know exact size/type). One bad thing during the process: a bolt stripped off in the turbo and we had to drill it out. All should be fine now and no rethreading should be needed.

I'll post here immediately once I get the dyno with the TBE and both graphs. Hope this information is helpful to anybody who might care...I know I like it so far!

 

It is best to dyno in 4th gear... But great numbers! Can't wait to see your air/fuel ratios.

 

Yeah, that's what I had thought but when I asked him third is what he told me. Why exactly is it best to dyno in one gear versus the other?

 

the 4th gear was for older trannys with a straight through 1:1 drive in fourth. Just make sure you use the same before and after. Different gears will give a different reading.

Matt

 

It's best to use the gear closest to 1:1 (generally 4th gear) to ensure the engine is fully loaded, and to make comparisons with your friends on NAM easier.

 

Those numbers are pretty typical. For the record, it's best to dyno in the SAME gear between base and test runs, however generally 4th gear or whatever the 1:1 gear is is generally accepted as "the norm".

 

Possibly they did it in 3rd because that is what is 1:1 in a Civic (they're a Honda shop primarily). Not sure though. Oh well, from what I've gathered it's not that big of a deal, as the most important part is making sure the next run is in 3rd gear as well. Thanks for the input.

Oh yeah, Ryan, we ended up using a resonator, as I got a highflow SS from Vibrant for $50. So hopefully it doesn't sound like a Harley when we're done.

 

I'm pretty sure they didn't run Air/Fuel ratios on that dyno run...because I think they were throwing it in for free. I could see about getting them on the post TBE run, but will that do you guys much good without a stock A:F to compare to? Also, found out it's a DynoJet.

 

Post mod air/fuel would be great too.

 

Okay, so they said that we probably won't be able to replace the stock heat shield due to lack of bottom bracket that was on the OEM downpipe. Did anyone else have this problem (Ryephile?)? I'm wondering if this is going to be waaay too much heat. We're heat-wrapping as much as we can, but I still wonder if we should try to jimmy the thing to at least cover as much as we can. Also, on the air/fuel ratios, I don't know if we'll be able to do them on the post-TBE run either due to the O2 bung not being available as it will be an extended one (to fake out O2); they're tailpipe sensor is broken.

 

I used the factory downpipe bracket and all factory heat sheilds with my 3" tubing. There's no reason they can't too unless they're being lazy and sloppy. Insist on all factory heat sheilding.

 

So I got the car back. First things first: wow, it is loud. Okay, not super loud, but just like Ryan was explaining with his system: loud on engine braking and loud on WOT above 3000rpm.

Build-wise, the quick run-down is 2.5" system, 304SS, no cats, Vibrant high-flow resonator, Magnaflow 3" in dual 2.5" out muffler (had to use a 2.5"-3" adapter because I had already bought the muffler when I thought I was going to build a 3" system), 3.5" polished tips.

So on to the dynos. I'll post the graphs as soon as I can but I'll try to explain all the numbers first. It was kind of a complicated process but I'll streamline the day: they called me after they finished it and dynoed it and told me that with the new system it lost power. I was like "wtf?!?!" so I drove down there. I asked them if they had let it warm up and had Sport button pushed and they said yes. Then I asked if they turned the ignition on/off a few times. They said no but that they had disconnected/reconnected the battery. So I figured we would give that a try and then it got fun. So I restarted the car about 4 times and then we dynoed it. It posted a few hp/tq above stock. Again: a few more. And so on for the next 5 runs. So the end result was a solid 12hp/12tq gain all the way across the power band (peak 189whp/206wtq). These runs were in 3rd gear as I wanted to stick with what the stock dyno was done in. The only thing is, turns out my tires were low on air (I never tended to them with the weather change), so that may account for a couple hp.

As far as the rest of the build goes, the reason we didn't use the stock downpipe bracket for the heatshield is because I wanted to leave my stock system completely intact. So we were able to get the top heat shield back on, but the bottom bracket is hanging loose (it shakes a little but you can't tell or hear it when you're driving. We were unable to get the side heatshield back on, but I may tinker with it in a few days to see what I can do. We did heatwrap the downpipe, so hopefully that somewhat makes up for it.

Sorry Terry, we were unable to do air/fuel ratios. I did however do a 4th gear run and it ended up being the same (I think 1hp/1tq difference). The only thing I'm kind of worried about at this point is what the very bottom of the powerband looks like because the dyno plots start at like 2900rpm. I know that there's not too much more below that, but I'm a city-driver and I really care the most about 1500-3000rpm range. But oh well, I'm pretty sure by the butt dyno that there wasn't the same loss in power that Ryan saw.

So I think that's it. What do you guys think? Any questions I can answer, just go ahead.

 

Cool!!

How much did it all cost you? The TBE...not including the dynos...

 

It cost me $1010, with the dynoes (he only charge me $10 for the dynoes since I was spending so much). So this saved me about $800 over Alta's setup (downpipe+cat-back+shipping).

 

No problem! Looks like nice gains with your new exhaust.

 

Question for ya, Have you gotten any cels with no cats and all. I'm interested in added a Dp to my custom 3" exhaust but have been weary. And please post some pics, I would love to see the set up.

 

So the great thing is I haven't had any CELs yet. We ended up using an O2 bung which is essentially a 5" piece of small tube that we welded into the downpipe an then ran the O2 sensor into it. This simply pulls the O2 sensor out of the direct flow of the exhaust gasses. I'll try to get a picture of it(and the rest of the setup) as soon as I can.

The only problem I've had thus far is a weird one: my flat tire light is on. It first came on after we dynoed it so we checked pressures and they were in fact low but after reinflating the tires, it is still on. I even rechecked pressures this morning and they're still fine. May be unrelated, but weird nonetheless.

 

Did you RESET the tire pressure monitor? It doesn't do it by itself.

 

I'm an idiot. That fixed it.

Now for some bad news: CEL just popped on. 30 miles and I got one. Any thoughts?

 

Wait for BMS o2 simms.

 

Okay, so here's a few images I snapped on my iPhone earlier. Not great, but you can get the idea of the tips. They're 3.5" each and the fitment is great. May be slightly big, but they look pretty stock to me due to the placement and the rolled lips.

 

get a friggin cat for that street car!

Matt

 

So here are the dyno graphs. This first one shows the TBE before ECU learning (blue) compared to stock (red). Notice the power loss all the way across the chart.



This one shows the TBE after starting and stopping the engine about 5 times and doing a few runs. Same goes for this one color-wise (stock is red, TBE is blue).



You can see that I gained a hefty amount of both HP and TQ all the way across the powerband. Another interesting point is that stock it took about 5.5 seconds to run through 3rd gear but after the TBE it blazed through the gear in 5.0 seconds. I wish that the graphs started a little earlier but I didn't know at the time that he started catching so late (I guess this is what I get for going to a Honda shop--they're used to only seeing power above 4k). Oh well. What you all think?

 

you spent a lot of money to ditch a cat, and get a small boost in power and a bit bigger boost in torque.

FWIW, I don't mean this to be a jerk. I too "rolled my own" exhaust for my R53, and it was so friggin noisy that it's next to my shed and the one-ball went back on. I think we both learned that there's more to making a good exhaust than just having one welded up.

If you don't have good design software, there's tons of trial and error to get something good. If you do have good software, there's less trial and error, but still some. Neither of us had good software!

Matt

ps, get a friggin cat for your street car!

 

Yes, I somewhat agree with you. I ended up spending a little bit more than I wanted and the system is a little bit louder than I wanted, but it was the best option I had. As far as the cat goes, I guess my train of thought was that even without one (which would save me about $150) my car would still get better gas mileage and still produce better emissions than every F350 out there, which somewhat soothed any remorse I was having on the situation. Also, like I mentioned earlier in the thread, I rarely even drive above 3000rpm because I drive about 2 miles per day between my school and my house, so I'm not WOT killing the ozone constantly. But with all that said, I probably agree with you on it not being the absolute best option. If I had more patience I would have waited for RMW to release their TBE for around $1200 (Jan told me on the phone) and been done with it, but even then it would be about $150 more with shipping and I've still saved $300+.

But I guess this is where I am now, and I'm happy with the gains, so I can't really complain. I suppose the story will go differently in 10 years when I have a little bit more money to spend.