The path to power and enlightenment

[Zdfrg]

It's time to educate myself some more so I can possibly add more power to my STI. I appreciate any input that more educated and wiser folks on here can privide. So on the the ride then goals:

MY06 STI 56,600 miles (California)
Cobb AP ACN Stg 2 Map
Invidia Bellmouth catless DP wrapped
Invidia N1 resonnated exhaust (soon to be replaced with Cobb 3" exhaust)
Shell Rotela oil 5-40W

The desire for me now is to keep the feeling of accelaration if have from 1st-3rd but give me a bit more top so 5th doesnt feel like dookie. I don't really know how to go about that so I'll toss in my thought; first off a pro tune is in the future but I only want to do it once after I complete all other power mods. Tuner will most likely be GST in Hayward. So my general plan is to upgrade injectors (850cc??), headers, up pipe, possibly a turbo if necessary (have no idea which one would be best). I don't have any plans to build the motor at this time nor do I want too.

I do have one even more noob question concerning the dyno maps i've seen. At the end of the run the graph always tails off and boost tapers down. I know it has to do with air flow and safety but I don't understand the mechanics of it. Also i've read that cams (272 I think) allow the engine to breath more up top. Not bringing into costs or feasibility but could installation of a higher cam in a stock motor allow better top end. I imagine the cost and other supporting mods are a priority before then. Thanks and I hope I was able to explain well enough to have my questions answered.

Jose

 

[Zdfrg]

Fuel of choice still ACN91 piss gas? I'd look to options for higher octane through another fuel or supplemental systems.

Stock STi will max out fuel system if tuned properly. Best mods IMO are: injectors, fuel pump, boost controller. I personally like Hallman Manual Boost controllers because of the reliability and simplicity of the MBC.

TBH, I've seen the taper on many "professional tunes." I believe it is a matter of style as I have now seen 20+ subaru with stage 2 ish mods that hold power to redline and nearly hold torque to redline.

Cams: yes, most longer duration cams like that require aftermarket springs. See my camshaft thread for more info.

Yep, fuel choice is still cali piss. E85 is not conviniently available to mke the switch. I've thought about meth injection and it would be amazing for me here but I'm not entirely sold on adding more complexity or anohter possible point of failure. I forgot to mention it but i was thinking of an EBCS over a manual. I drive up to Lake Tahoe/Reno often and that a change of 7,000 feet in elevation and IIRC with an EBCS it would be less complex to deal with.

What's your thoughts on switching to a twin scroll setup? I saw that you were testing the Moore Performance header. It's something I've contemplated for some time but I have yet to find a complete system that will work together with synergy and justify the cost. I see it as a way to increase the longevity of our motors with better scavenging and more equal temps across combustion chambers.

Do you have any vendors that you would recomend? I don't need it to be a big name just good stuff that works. Thanks

 

[ICY STi]

What is the price of E85 compared to 93 oct. just curious. Never had the ability or need to use it.

 

[holyscoobysnacks!]

E85 is usually around 50-75 cents cheaper in some areas.

The closest e85 station to me is like 40 miles away...

 

[Zdfrg]

That kind of elevation change I have not dealt with.

Some of the failsafe systems are rather impressive.

What do you mean "recommend a vendor?"

What parts manufactures that you believe in and trust their stuff. You can PM me.

Last I checked E85 in my area was 3.89 or so.

 

[Spamby]

It's time to educate myself some more so I can possibly add more power to my STI. I appreciate any input that more educated and wiser folks on here can privide. So on the the ride then goals:

MY06 STI 56,600 miles (California)
Cobb AP ACN Stg 2 Map
Invidia Bellmouth catless DP wrapped
Invidia N1 resonnated exhaust (soon to be replaced with Cobb 3" exhaust)
Shell Rotela oil 5-40W

The desire for me now is to keep the feeling of accelaration if have from 1st-3rd but give me a bit more top so 5th doesnt feel like dookie. I don't really know how to go about that so I'll toss in my thought; first off a pro tune is in the future but I only want to do it once after I complete all other power mods. Tuner will most likely be GST in Hayward. So my general plan is to upgrade injectors (850cc??), headers, up pipe, possibly a turbo if necessary (have no idea which one would be best). I don't have any plans to build the motor at this time nor do I want too.

I do have one even more noob question concerning the dyno maps i've seen. At the end of the run the graph always tails off and boost tapers down. I know it has to do with air flow and safety but I don't understand the mechanics of it. Also i've read that cams (272 I think) allow the engine to breath more up top. Not bringing into costs or feasibility but could installation of a higher cam in a stock motor allow better top end. I imagine the cost and other supporting mods are a priority before then. Thanks and I hope I was able to explain well enough to have my questions answered.

Jose

Honestly, you should speak with your tuner to see what they recommend. He/she should be able to take into account your feelings and goals and steer you into the right direction. With that said, I will try to help you, though I am no expert and am giving mostly opinions/observations.

A protune alone might just get you what you desire. A tuner should be able to get you more of what you desire out of the top end, within reason.

E85 looks to be the biggest bang for the buck on stock motors/turbos. Many E85 cars are putting down comparable numbers to the ones that have gone (smaller) turbo, etc on pump gas. E85 on a small turbo upgrade should be an animal. However, if E85 isn't readily or conveniently available to you, then well, that sucks.

Water/meth/alky, should give you good gains but as you said adding another potential point of failure is no bueno. This is the reason I never went with meth/h2o.

If 91ACN is truly dog piss, then maybe try something like Torco Accelerator. I used this for a stint in the STi and CTT and did notice a difference in performance. I don't know exactly what is in it but i think it is supposed to help raise the antiknock properties of your petrol and thus keeping your ECU from pulling timing. In theory, you should be able to tune more aggressively. However, keeping that crap on hand is expensive and if you miss a dose with an aggressive tune, it could be bad. There is too much mystery behind this stuff for me to call it a 100% viable option.

I don't believe headers are a worthwhile investment until you start going big on the turbo. Headers may be more beneficial if you start doing cam and head work, as well. If you must go headers with a small snail? Keep the tubing diameter close to stock and the flanges thick. Or better yet, get a factory set that have been ported.

Cams can help but remember they are just the gate keeper. Without other supporting mods, head work, headers, maybe even turbo, they may even create a problem. They might shift too much power up in the band and leave you weak down low. Our cars, IMO, are in need of more help down low rather than up top. After all, the majority of your driving is in the lower end of the spectrum rather than up high.

If E85, meth/h2o are out of the question and you feel like a protune alone may not get you what you want and you don't want to build your motor, then a small turbo on pump gas could be your bill. Look at turbos like the 18g, 20g, DOM 1.5xtr, FP green, AVO380, etc, etc, etc. Or maybe even a VF48 swap. VF48 seems to be a little better up top than the previous gen turbos. A twin scroll would be cool but I don't see them done very often, maybe cause of cost?

As for vendors? Choose your build plan and then research the vendors involved in those parts needed. There is more than enough info at your fingertips. Google those digits until they are bloody stumps.

 

[Td_d]

If 91ACN is truly dog piss, then maybe try something like Torco Accelerator. I used this for a stint in the STi and CTT and did notice a difference in performance. I don't know exactly what is in it but i think it is supposed to help raise the antiknock properties of your petrol and thus keeping your ECU from pulling timing. In theory, you should be able to tune more aggressively. However, keeping that crap on hand is expensive and if you miss a dose with an aggressive tune, it could be bad. There is too much mystery behind this stuff for me to call it a 100% viable option.

It's an additive called MMT - very effective in raising the knock threshold of poor gas. Downside - bloody expensive, and long term use leaves deposits on everything - I've seen an engine opened up after a long time of using this stuff, brown staining everywhere.

 

[Zdfrg]

I like most of what Process West makes, Grimmspeed does good work especially for the price, I like FIC injectors... What all are you wanting to get?

To be honest, I want to go twin scroll. The more I read about the technology the advantages over single scroll setups become more obvious. There are only two main reasons why I see people going with a single scroll: $$$ and having lots of proven(performance) parts. If I had the option of picking a twin scroll setup that was proven but cost no more than $500 over a single scroll I know what I would pick. I just don't know who to buy from so I get a good matched set of parts that work great together.


Do you have a recomendation for a coilover setup?