Sarang

So between the stuff on the firewall and the intake manifold on the driver's side it's about 11 inches. Between the center of the intake manifold and the firewall is a little over 12 inches. You have about 16 inched before you'd hit the hoses and whatnot over by where the stock charge pipe routes. You could fit something about five inches thick with ease, but it looks like 6 inches thick is doable. For something like this, I think mocking up a model out of cardboard would be the best possible option, because it's hard to be sure that a corner won't foul something making it all impossible.

My car is just outside and I have a tape measure, but I'm not sure that I understand what measurements you need. I'm going to go get some right now, but give me some more detail.

20G turbo is on the way. Injectors are sitting in my closet. Now I'm working on scheduling install and tune.

Tuning Alliance has a flex fuel kit and wide band O2 kit listed on their website. I inquired about 5th gen LGT compatibility. http://tuningalliance.com

Stewdogg: When will yours be up and running? I can't wait to hear your impressions. Islandborn: THANK YOU! That is exactly the kind of feedback that I was hoping for. I do like my lower RPM fun around the city, I'm just thinking about how I'd like some more higher up. Flex fuel is something I'm interested in, but I'm sort of waffling between doing that first or upgrading the turbo, or saying screw it and doing everything. But then again I don't really want to blow my engine next week...

Agreed. Say, can you give me some insight into your preference between the 20G and 18G? Since my exhaust cams shouldn't limit me at that level I'm torn between the two. You dyno on Cobb's website seems to show that your 20G reached 325 torque only ~200rpm after the 18G. What's that like driving around town? Like, how different is it if you're not getting on it? When do you notice the difference most? Is the top end very noticeable? I think you've said before that you prefer the 18G. Anything you can tell me about the differences would be greatly appreciated. (I'm going to go read the Power Roadblocks and Solutions thread for the nth time...)

I took a 3rd and 4th gear WOT log today to see what difference the TGV deletes and STI exhaust cams make without getting re tuned... and Gteaser was correct, no difference at all. Both runs were within 3%. Not even worth posting IMO.

Well I got my car back today. New clutch fork, clutch, STI exhaust cams, TGV deletes, and some other miscellaneous stuff like a new serpentine belt. I wish I could say that I feel a difference, but all I'm feeling right now is the clutch damper delete. I stalled twice on the way home. So I need to get used to that I guess. I'll get a WOT log when I get the chance to see if I can see any difference.

To play devil's advocate, and because I don't think I fully understand all this: Why not just set target boost much lower in the low rpm range - such as 12psi at 2500, 15psi at 3000, and full boost after 3000? Would that address the concern? On the other hand, to combat the added spool of a slightly larger turbo, you could just shift 500 rpm higher all the time, right? (once it's appropriately warmed up of course) I'm thinking that if you used to shift at 3500rpm getting on the freeway, bump it up to 4000rpm and the 18G should seem to spool similarly to your stock turbo. Does that make sense? Please don't hesitate to school me here if I have it all wrong. I'm trying to learn and be able to make informed choices about what I want for my car.

I am interested in this idea. I have looked somewhat, and haven't found good comparisons between the 18G and 16G on the 2.5. Do you have any information that I might not have? If it is really just 97% of the power and spool 300rpm sooner, then that sounds great.

Yeah so you would need a pump, radiator hose, the radiator/heat exchanger, and the AWIC. You'd have to fab up the charge pipe, as well as mounting solutions for the AWIC and heat exchanger. I have thought about it some, but I didn't specifically price it up. You would need to wire in the pump to run all the time that the car is on. If the radiator got good enough flow - such as by taking up the entire lower opening of the bumper - then you might not really need ducting or puller fans.

Would you consider something like this? http://www.frozenboost.com/liquid-air-intercooler/water-to-air-intercooler-p-1006.html You'd have to deal with mounting, but I bet the type 101 heat exchanger would fit nicely between the crash bar and the bottom frame. I wonder sometimes of that's what I should have done instead of my FMIC, but I'm not willing to shell out the time, effort, and money to switch to an AWIC.

So I actually stopped by the shop working on my car today and he was in the middle of putting STI exhaust cams in my car. He was able to show me that our intake cams are the same part# exactly, while our exhaust cams are not and have noticeably less lift. I intend to get a couple of WOT pulls of my car when I get it back so that we can get an idea of what STI exhaust cams and TGV deletes will do on an otherwise stage 2 ish car. I didn't think to take pictures, but maybe I should have.

THANK YOU! Somehow I haven't read that thread before...

Also here is my email to BNR: and here is his response: So that's good to know that the ebay special vf54 would work for a core.

Thanks for the input guys, I'm digesting it. It comes to my attention that flex fuel might be better $/hp compared to just a turbo upgrade. Why would the 18G be better than the HTA68 for ACN91? especially if they spool similarly I do want to avoid too large of a turbo; I'm pretty averse to lag.

I'll update too: Now 30; Project Manager; added group N transmission mount and now adding STI exhaust cams. Considering my next upgrades, possibly a hybrid turbo or flex fuel.

That is a really compelling data point, because it looks like it reaches 15psi at 3000 rpm and holds 17.8 psi to red line!

Thank you. I am using 15psi as a benchmark to use to get an idea of how they would spool related to each other. I suspect that I would end up running 18-20 psi, but I would likely leave that up to my tuner.

Hey guys I am seriously considering upgrading my turbo and I'd like your input on which to go with. In particular, I am interested in spool and power increase over stock on my ACN91. I am upgrading my cams, although I have not decided yet on GSC S1 or just STI exhaust cams. BNR offers an 18g, 20g and HTA71. There are also several 20g options on ebay, but I would be more confident in BNR. Spool characteristics: Stock: 15PSI @ ~2700 - 3000 rpm (lots of dynos) 18g: 15PSI @ ~3000 rpm 20g: 15PSI @ ~3400 or ~3000 rpm (two different dynos, both 93) HTA71: no info found, but one HTA68 15PSI @ ~3100 rpm Does anyone have any more info on spool for the upgrade options? If the HTA71 spools similar to the 18g, but has more flow potential than the 20g (with upgraded cams), then it's the clear winner... right? I'd really appreciate any input. I would hate to spend this kind of money and later find out I missed something. Thanks!

Would you have a dyno that you could post pretty please? Even a virtual dyno would be appreciated.

Only making the noise around a specific RPM sounds like something is resonating to me. Like a vibration. It's hard to assist with diagnosis without hearing it in person though. I would be very wary of a dealer's suggestions with this type of thing. Sometimes they like to use a big repair as a catch-all for something they can't figure out. If they tell you it's and engine mount or you need to replace your ECU it would be a big red flag.

You could grab the clutch hard line union that is used for the damper delete. The part costs like $30 from the dealer and you only need a 12mm socket and 10mm wrench to get it off.

I hate hate hate replacing fender lines. I've bought three. Last time I used nuts and bolts in lieu of the big black plastic clips. It felt like overkill, but I haven't had to drop $40 on another liner yet.

~50k miles more or less