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My experience with BrenTuning (long read!)


SCGT

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Posted this over on NES, but thought some people here may benefit.

 

I began my modifications with my 2009 legacy gt the same place most people do; an accessport. Started off with a Rallitek stage 1 off the shelf map, and began to lust after a turbo back and the allure of stage 2. A downpipe later, I wasn't pleased with the OTS cobb stage 2. I got some over boost codes, and the car just didn't run smooth at all. The power came on at ~3500 rpms like a switch, it would hesitate, and didn't seem consistent. I figured the obvious next step was a pro-tune, which I got from an authorized cobb pro-tuner. At this point I'll mention that I usually run 93 octane, but for the tune I ran 91 octane and requested a conservative (smooth) tune. It's a stage 2 legacy, fun, but not a race car.

 

 

Well, the pro-tune was worse than the OTS map, it felt fine for a few days, then started to be inconsistent. About this point in time I learned about how one ought to do logs from time to time to see what sort of state your engine is in. I was surprised to see I had quite a bit of knock. I emailed the tuner who pulled some timing. We went back and forth like this for a while, me taking logs, him pulling timing, until I had so little timing that I was under OTS power levels and still knocking. The tuner basically told me to stop worrying about it. I had one run where my DAM hit .1. Once more, I showed the log to the pro-tuner and was told it was a nuisance, there was no way the car could knock with that little timing.

 

 

Since I appeared to be the only one in the universe with this unique problem, and the car seemed to be mechanically sound, I decided to start asking around. Some of the guys from New England Subarus recommended Brentuning. In particular, Eric (shtbxr22 on NES) took some time to help me out and quietly said if you want a smooth, conservative tune that won't blow up your engine, go talk to Bren.

 

 

I offered to pay Bren to view my old cobb pro-tuned logs to help me diagnose the problem. He told me to send him the logs, no charge. Being the professional that he is, he wouldn't say anything bad about the previous tuner, just what he believed the problem to be. I decided to give Bren a go with a road tune based on his straight forward answer, professionalism, and of course the recommendations from others.

 

 

I'm an engineer who is just beginning to learn about modification on cars, so I will admit that I'm something of a pain in the ass. I have excellent technical ability, but not much knowledge about this stuff (yet), so I have a lot of questions. Bren answered them all. Not only that, but if he didn't know the answer, he would tell me as such, which to me is infinitely better than the normal: make up something that sounds good.

 

 

Bren (and Eric, who happened to be there working on Bren's very nice BMW) did a quick check over on the car (including a boost leak check), and we were off. He told me what he was doing every step of the way, what he was checking, how the car was responding. After all my issues with knock, I was actually pretty anxious! He got the tune pretty good, then pulled over and asked me about my goals before he continued. How long was I going to keep the car, what did I want to do with it, how much power would I like to end up with after subsequent modifications, what my driving style was, and the list goes on. Bren then continued refining the tune, taking the time he needed. He mentioned some people want him to hurry, they want a quick tune only, and that's not how he does his work.

 

 

Bren takes pride in his work, working tables over and over, smoothing them out, interpolating, making minor changes here and there, constantly refining. It's in the details and it shows. I went to Bren hoping for my car to stop knocking, and at that point I honestly couldn't care less what power output it had, because with the knock I was seeing at WOT every time... I knew it was a matter of time before I was at zero wheel horsepower on the side of the road.

 

 

Bren explained to me the difference between a dangerous tune and a safe tune is often only 10 whp or so, that there was no reason why you couldn't have it all if the tune was good. He made good on that statement, I ended up with 278 whp and 321 wtq, which was ~53 whp (and a PILE of torque) over the cobb OTS stage 2 and most importantly, no knocking. Zero. None.

 

 

I got tuned by Bren on Sept 26th and held off on posting this until I could get some good info (see learning view below, this is about 1500 or so miles after the tune). I love the car. It feels like a different car. I actually have throttle response that I can modulate, the car has so much more torque down low that it's ridiculous, it's smooth and has been since the tune, and it just plain drives better. WOT is so much faster than before that it's laughable to compare, but as I alluded to above, it's the daily driving that really made the big difference. The car is easier to drive. Bren does magic with AVCS and if you get tuned by him you'll see what I mean. There is no aspect of the engine performance and feel that has not been improved.

 

 

Highly recommended!

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Hi there, I should have posted my mods too.

 

Stock airbox, AVO drop in filter

Cobb Catted Downpipe

Borla Exhaust

Forge BPV (Bren's recommendation, I guess the OEM ones can leak a bit)

I changed the plugs to one step colder, but that was after the tune based on Bren's recommendation.

 

I particularly like that my SI drive is now 12/16/18 PSI.

 

Next is a FMIC, walbro 255, and an intake (not sure which one yet). Love the torque and how smooth it is.

2009LGTstg2bpv18psi.thumb.jpg.5667e0f78479e99c0fc3e13233c593d0.jpg

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Forge BPV (Bren's recommendation, I guess the OEM ones can leak a bit)

 

Yeah they leak quite a bit. I'll be upgrading to one since I'll be turning up the boost past 22 PSI with the 20G

Surprised you didn't get a bigger intake. It helped a lot on my car and was easy to tune.

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Surprised you didn't get a bigger intake. It helped a lot on my car and was easy to tune.

 

All in stages, the intake is next with the FMIC and fuel pump. Honestly I was so upset with my previous tune and the constant knocking, I just needed a safe tune period. I wasn't happy with what I saw logged on the Cobb OTS map either (I got knocking on the 91 oct map and I put 93 oct in the car), and IMO it's junk to blame the engine when it's clearly a tuning issue. I only got the Forge b/c I overnight shipped it to be installed in time for my scheduled tune, otherwise I would have gone and got the tune as I was.

 

After the next round of mods... injectors and a turbo. Somewhere in here I'll be replacing a clutch too. ;)

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  • 3 weeks later...
  • 2 months later...

Update!

 

Saturday 1/22 started pretty early in the morning when I sea foamed my car around 6:30 and began the trek to see Eric Bernard and his friend Shaun Flanagan. Not much smoke out of the car with the sea foaming, but enough to make it worth while.

 

After I met up with Eric and Shaun, they began pulling the car apart and installing the FMIC. Eric has established himself as my go-to guy for work on the car, and he wanted Shaun there since he’s become something of an expert in the racer-x FMIC install. They each started working on separate things and I stood around drinking coffee, losing parts, and getting in the way. The install went without a hitch; both of these guys know what their doing and it plainly shows. Shaun treated my car as if it were his own; maybe even better; and was meticulous about the precision with the bumper cover trimming. Great job to both of them, and they’re (of course) highly recommended, no questions asked. After the FMIC install, I changed my air filter to a new AEM one, and Eric changed my oil.

 

Bren said I could drive my car in “S” mode (16 psi) down to the dyno, but since I’m a wimp and noted that the car felt “different”, I pretty much kept it out of boost. We met up at PSI racing in Auburn, MA. Eric helped with some adjustments to the FMIC piping (one part was hitting the master cylinder) and Bren took a baseline.

 

This is my third tune from Bren. My last tune was winter gas, walbro 255, grimmspeed BCS, KStech intake, forge bpv, NGK plugs 1 step colder, oem TMIC, cobb catted downpipe and borla catback. On a road tune, with lousy new england winter gas, I ended up with 283 whp and 305 wtq. With the same lousy gas, the same tune (designed for the TMIC) but with the sweet new FMIC installed the car put down 279 whp and 330 wtq. This is interesting on two levels. The first is that I gained a substantial amount of torque due to the much better intercooling; clearly it matters. I did get a ceramic coating on the FMIC piping, and a thermal dispersant coating on the core, the object of which was to increase efficiency.

 

The second is a bit of a digression but has to do with road tuning and dyno numbers, how they compare and do they read high or low. When I was scheduling my very first tune with Bren he told me the road tuning dyno graph software he uses would give results very similar to a dynapack (since that’s what he uses), within a percent or two. Since I’m a mechanical engineer I figured that you could ABSOLUTELY relate one to the other if the right correction factors were used for road dyno software and the road/track conditions were adequate. Moreover, anyone who understands a vehicle dyno will realize that they’re really mostly useful for comparing changes. If it reads high, or low, as long as you use the same or similar dyno then you’ll know if you’re making progress and if your modifications/tunes are a good value for the dollar. As I’ve come to expect, Bren was true to his word and I could see the dyno computer monitor reproducing what he had already told me it would. Awesome!

 

Watching your car get wrung out on a dyno is anxiety causing. It’s different when YOU’RE the one driving it, at speed, wind noise, etc, but in person watching ‘er go makes you worry. Bren did a bunch of pulls and we all were surprised how much more power (and especially torque) the car made with the FMIC. I don’t know how many pulls Bren made with the car, but I kept an eye on the dynapack computer and watched the torque transform from a perfect upside down vee shape into a very nice and flat torque curve.

 

Bren kept tuning and I asked him how things were going, if the car felt healthy, all the questions you worry about when you see your car getting wrung out on a dyno. He told me that my VF46 was breaking records for power output and he hadn’t done anything crazy, and that the car was still running pig rich in certain RPM ranges. I saw the number climb from 279 to 285 to 290 then 295. On a couple of runs Bren made the car go over 300 whp on a VF46, which is fairly unusual from what I hear. If you read some of my older tuning reviews of Bren, I believe I mention that my turbo seems a bit of a freak and wants to spool early. Bren made this work to my advantage now that I had a better intercooler. We laughed at the numbers we were seeing, guessing that seeing ~300 whp from a VF46 would upset some people.

 

Bren explained what he was doing when I’d walk over and see how things were going, and without me even asking, mentioned that he was keeping things very conservative. At one point he added a little timing, and didn’t make any more power. He added a little more and made 3 hp more. He added another 2 degrees and the car pulled 2 degrees, so he took it all the way back to where it was in the first place, dropping the power below what was pulling zero degrees just to give me a little extra margin of safety. This is what I want, and what I like, and I really appreciate that Bren listens to my requests; my legacy is no race car, just a fun daily driver.

 

[ame=http://www.youtube.com/watch?v=0anijpOPZHY]YouTube - Bren Tuning Pulls, 2009 Legacy GT[/ame]

 

A couple more pulls and Bren said the car was making the same power over and over, even heat soaked, which meant it was tuned very conservatively. We ended the dyno runs with almost 300 whp and 365 wtq. Again, the numbers don’t really matter to me, what matters is consistency, drivability, reliability, and finally, what we’re all here for, having fun driving your car. That being said, this thing moves! It actually has a top end now and you can guess how the extra torque feels.

 

[ame=http://www.youtube.com/watch?v=YSdHNqQ-Tr4]YouTube - Bren Tuning: 295 over and over, 2009 Subaru Legacy GT[/ame]

 

For economy or very slippery conditions, “I” mode is at 5.5 psi, and made 140 whp. You can almost legally street race with 140 whp, since even standing on it, you’re going no where fast, lol!

 

They took the car off the dyno, Bren brough his laptop, Eric hopped in the back seat, and we went out to polish off the tune. Bren made a couple of minor adjustments, asking me a few questions, and before I knew it we were back at the shop. I hung out a little while longer and watched Bren start his next tune, then finally headed home. Since I like to worry about things, I did a couple learning views on the way home. Perfect. Nothing pulled, A/F trims very good. Normal for a Bren tune.

 

What a day! Sea foaming, FMIC install, boost leak check, oil change, air filter change, dyno tuning, road tune for finalizing it then the 2 hour ride back to Maine.

 

Bren has firmly established himself not only as a great tuner, but my tuner. As always, highly recommended. Great job Bren, I’m happy to have you tuning my car.

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Glad you're happy with the results. How much boost did your tuner end up running? Looks like 19.5 in the video

 

For fun I overlayed my stage 2.5 mustang dyno chart with your dynapack one. I increased the size of my plot while maintaining the aspect ratio and and getting the RPM scaling to match. Look what I determined :lol:

 

Notice how the torque curves are essentially identical yet the whp is very different. This could be a result of the Mustang dyno not exactly reading my RPM for that pull and miscalculating the whp. Or, the two dynos might just calculate whp differently, which is more likely.

922338861_mustangoverlaydynapack.thumb.jpg.93224ca637a8ed0d373199d2ec21acac.jpg

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Hey Franz!

 

Thanks for your post. Interesting data, I'll ask Bren about it. I know he used a Dynapack 2000. Some quick searching does show that Dynapacks read higher than many other dynos, my happiness with the tune is certainly not number based; the car pulls hard, runs smooth, and learning view is perfect every time. Honestly I couldn't care less if it read 270, or 240, or whatever, as long as it gets better with more mods!!!

 

What did your WHP end up being on that graph? I can't quite tell, looks like about 275ish? What were your next mods after that dyno graph? :icon_twis

 

I'll post back with what Bren says.

 

Edit/Update: He said he'd have to know the correction factor on the mustange to compare. This was at PSI in Auburn, MA, which reads the same as ECS in Springfield, ESP also. He said the average VF46 bolt on car makes 275-280 whp on this dyno with a FMIC. He has more of a presence over on newenglandsubaru's, or if there is any specific question you want to ask I can ask him. His write up on NES is here (mods, not sure if I can link to another forum, if a problem I'll delete): http://www.newenglandsubarus.com/forums/showthread.php?t=17528

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Yeah every dyno reads a little different, even ones of the same manufacturer. They can be calibrated differently. I believe my correction factor was 1.04 for that run, but I'm not exactly sure. The car made 296 wtq, 246 whp on mustang's graph. You have the right mindset. the numbers aren't important; how it drives and performs are. My car has a Perrin TMIC, but it stayed cool during the dyno pulls.

 

Also, if Bren spends a little more time tuning the turbo dynamics, he might be able to get that torque plateau a little flatter, but that's just nitpicking. I really like his approach to doing the timing. Adding little by little until it reaches the knock threshold, then dialing it back. Did he change the AVCS mapping very much?

 

I just finished my stage 3 build and am in the middle of tuning it. I probably won't dyno it until I get the full 3" exhaust on and new 3BAR MAP sensor. I've got a BNR 20G on it now with custom fuel system.

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  • 4 weeks later...
How'd it go?

 

tune came out real smooth through out the power band & ran into a few small problems.

 

first was from the base map he pull off at first bren detected boost leak & he ran a test it came out fine & said had to tweek the AEM CAI a bit more during tune.

 

during a 3rd-4th gear pull cylinder 1 coil pack plug pop off this cause CEL to come on and we're mis-firing all the way back to the shop - pull the coil pack off it check out fine & plug everything back in. adjusted a few map plug it back in.

then we're on the hwy did 2 3-4th gear dyno graph pull & Bren said the it show it made 285/311tq.

 

his suggestion was to upgrade fuel pump & change out this hose I have to my MBC that's causing boost spike & keep up with my oil level & changes.

 

today was the only day I took the car into red zone on 3-4 gear & really got on the car.

 

I think I should upgrade clutch & turbo soon along with fuel pump shortly cause with over 115k on stock fuel/turbo/clutch, is showing it's age.

 

after tuning I found the turbo spitting out oil on the compressor side, not sure if is the oil lines or compressor housings & i'm not loosing much on oil level.

 

 

http://i220.photobucket.com/albums/dd84/jaxx4k/utf-8BSU1HMDEwMjUtMjAxMTAyMjAtMTU0Ni5qcGc.jpg

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^^ i don't really get on the car like it did today.. it should last a bit if i baby it...

 

when I did the dp/up install i check the turbo and there's no play at all, so it can be some old lines and what not, I'll check my oil & keep monitor it.

 

i do have a few option.

 

BNR 16G+oil line+ shipping =$890.00 + installation & retune another $500.00 = total$1390.00 total

 

A used vf40 - $3-400 & new oil lines + installation $325 = total $725.00

 

A used vf46 -$4-500 & new oil lines + installation & retune another $575.00 = total $1175

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