here are some pics of the Buschur Racing 3" Turbo Back Exhaust (TBE) with a test pipe instead of the high flow cat and the bullet muffler. I think this is going to flow so much better than the stock 2.5" equipement. I can damn near shove my arm through the muffler opening. I also included some pics of the 780cc injectors I also purchased from Buschur.

 

guess what I did tonight after work

yep, I installed the BR turbo back exhaust myself on my back under the car and it was a long process like that. I didn't install the ebay 02 housing yet, I'll do that this weekend maybe and I don't need the injectors yet.

well the results are in I overlayed the before with stock exhaust vs BR TBE, test pipe and bullet muffler.

she's pig rich from the walbro install last week but you can see by simply changing out the exhaust it picked up 15 ft lbs of torque and 25 awhp. The car is worlds louder and it finally sounds like a screaming 4G63 I'll get some video/audio footage this weekend.

 

Just in case someone is having trouble understanding how I made such a gain over the stock exhaust... take a look at the stock bends and how small it is in places with a cat and several resonators. Now scroll up and look at the new Buschur exhaust. Night and day right?

also the new exhaust weighs 25lbs, the old felt like it was 2 or 3x that much, I could't believe how heavy it was when I was carrying it across the yard. I'll try to remember to scale it this weekend for comparison.

 

I think the stock exhaust is around 36 pounds from the cat-back, not sure about the stock cat or downpipe.

 

yeah I really felt like it was 50-75lbs.. unreal.

 

I hit fuel cut 2-3 times today... with the better exhaust it must be maxing the injectors out. I'll probably lean the tune a bit or go ahead and install the 780cc injectors to prepare for the cams.

 

Did you raise the boost limit values?

Damn, stock mid-pipe has two resonators. I guess that explains why the car is so quiet stock.

 

no, but I'm running a manual boost controller

 

I noticed the other night when I posted the before/after exhaust dyno runs that the low end torque was worse...I figured out the culprit. With the new exhaust the engine is moving much more air through and so the ECU sees more load than before and goes into a section of the timing map that retards timing too much. I'm not going to fix it yet because I want to get the new 02 housing installed first and see what gains it gives on the current tune.

 

Hmmm... maybe it controls the fuel too? I seem to recall the boost limit values being at 245 load, and you're definitely hitting over that.

Man, you don't want to see the timing map I have to run on 91 cali octane! I wish I could run your map without grenading.

 

I was looking a log from last night where I was hitting fuel cut which suggests the injectors aren't able to keep up anymore.

at 7562rpm I was seeing 15.87 injector pulse width and here's the forumula to find out the Injector Duty Cycle: IDC (%) = IPW*RPM/1200

100% Duty cycle.

 

yep that was it.. I changed the boost limit to 319 across the board, no more shutting down and I kept an eye on the NB02, it isn't leaning out so I must have more injector than I thought. I did read where another guy was calculating 120% IDC and not leaning out with his car, so clearly 100% IDC isn't the end of the road. I'll stick with the stock injectors for now, no need in complicating the tune until I need it.

 

sadly after going through hell to put that new 02 housing on I only saw ~ 2-5awhp at the most. I definately do not recommend this upgrade and if you ignore my advice don't do it until you're changing turbos because it's way too much work for the hp gains since youhave to pull the turbo to put it on.

I went out and started working on the tune since the car has been rich ever since I put the walbro fuel pump in a few weeks ago. I started out by doing a 4th gear pull from 3000 to 7500 and logging it. The NB02's showed the fuel getting richer after 6000 so I pulled out -3 from there to redline and logged again. Still no knock and it pulled noticeably better. I added 1* of timing from 100 load (0 psi) to max load (~ 30psi) and at every RPM range. I logged it again and the car felt stronger and still showed 1 or no knock. I added another degree of timing in the same place and the car really woke up and knock stayed under 3 counts this time. My previous best trap on the g-tech was before the walbro when I had the tune perfected which was 12.7 @ 108 and a 1.7 60' ... I didn't want to ruin the clutch so I took off soflty which gave me a 2.0 60' so I threw away 3 tenths but still managed a 12.8 and the mph shot up to 111.4

I also logged some 2nd gear pulls and had a best of 279 but I threw it out because I couldn't reproduce it after several attempts. I was able to make multiple 275awhp pulls.

what you're looking at here is:
black = stock exhaust untuned
red = Buschur Racing TBE, test pipe and bullet muffler
green = Buschur Racing TBE, test pipe, bullet muffler and 02 housing but tuned

check out the green torque line...roasting all 4 around a 90* bend is fun

 

Testing Buschur Racing's Turbo Back Exhaust with test pipe and bullet muffler

Click here to see Video

 

I ran one of my recent logs of a 4th gear pull through data log lab to see what the HP graph looks like... mods at the time were:
21psi, intake, 02 housing, Buschur turbo back exhaust, test pipe and bullet muffler, my custom tune based on knock and narrowband 02's. I had a little knock at 6800 or so as you can tell by the dip.