Tuning Tech. Subaru STI - AVCS vs. Adjustable Cam Gears. Which is better?

Toady we discuss the differences, pro's and cons of the Subaru AVCS system vs Fixed Adjustable cam gears on the same application. Car is a 2003 WRX with a hybrid JDM EJ207/257 swap (built 257 block with 207 heads) Engine management is a Haltech Elite 1500 ems with a Haltech IC7 dash display. Turbocharger is a Tomioka Racing T05-18g and the car has BC fixed adjustable cam gears. Previously the car had a functioning AVCS system using the Haltech engine management system bt as mechanical components started to have issues the customer switched to a fixed adjustable system.

[@hellis7310]

Love your videos!

[@dannyjoseph9613]

Dont know if anyone gives a shit but if you are stoned like me atm you can watch pretty much all of the latest movies on InstaFlixxer. I've been watching with my brother for the last couple of months xD

[@aaronaugust7904]

@Danny Joseph definitely, I have been using InstaFlixxer for since november myself =)

[@robmesaaz5737]

Appreciate the info. Thanks!

[@WT4T]

Appreciate you watching!

[@AmirPomen]

So.. after watching this... My take of whats the best will be keeping the avcs, get adjustable gear for exhaust side and retard the exhaust for about 3-5degree... Then tune the avcs for new dynamic airflow for the engine... Instant win! Fat torque with great top end numbers

[@WT4T]

That's exactly what we usually do on big power street/track cars

[@robbiedh02]

Do you think it is worth it to get the Cobb tuner for my 2020 Ascent to help with towing?

[@crazyDIYguy]

Do it open source for peanuts, it's not too hard. I use a vagcom which is trickier than just buying a tractrix 2.0.

[@JEwr_]

Would you recommend deleting avcs on a single avcs car for high HP build?

[@WT4T]

That really depends on vehicle use. If it's working well you'll see better spool and more midrange power which for a track/street car is nice. On a dedicated drag car it has little purpose and adds complication.

[@raviegoordial4950]

Shouldn't the tune be adjusted because the volumetric efficiency changes at given rpm x map?

[@WT4T]

Very minimal changes are made to VE but yes it does change. That's what's fun about MAF tuning, no changes needed.

[@NimaSomeh]

thanks

[@DJ_Driven]

Does the deleting the ACVS apply to the 2013 STI as well? Meaning if road racing or drag racing it's better to delete.

[@WT4T]

Yes you certainly can and I have. Tricky tuning issue however as the vehicle will only access the "non avcs" maps for fuel and timing and in COBB they are not live tuning maps, so it slows down the tuning process some on the dyno. On a stand alone it wouldn't be an issue.

[@byronboost]

its there any risk of going too negative too soon on the intake cam of a fa20 wrx

[@WT4T]

Too soon just means you aren't going to make maximum power, too much and the increased cylinder pressure can trigger a knock event. Just be smart, test as many positions as you can and overlay graphs to find which makes the most power without causing knock. With an adjustable system you don't need to just pick one. You get to use what position is best at every rpm. This is commonly known as developing a "cam timing curve" and while time consuming on the dyno most cars with similar setups will have similar curves so it's worth doing right at least once then just tweaking for future cars.

[@ronnieboucherthecrystalcraftsm]

2001 no avcs - i am interested in exhaust cam gears with a better turbo !

[@WT4T]

Adjustable intake makes the biggest difference realistically.

[@ronnieboucherthecrystalcraftsm]

@@WT4T THANK YOU SIR - i will get a set - with cams = kelford NZ cams = it is automatic trans .

[@xvsti722]

Hey could u tell me what he did with the solenoids in what kinda delete did he do? Remove them? Block them off? I was curious because im running into this same problems with the sti dual avcs and i wanna delete it

[@WT4T]

Solenoids stay in place, oil needs to pass through this area of the system to oil the front cam journal. You'll block the oil ports on the front of the cams themselves. There's writeups on nasioc and whatnot.

[@Germ629]

I'm just finishing up my ej257 swap in my 02 WRX. I installed bc272 non avcs cams and non avcs intake/exhaust gears on. I triple checked the timing belt and alignment when building the engine. I'm having an issue with no power and after testing everything... Pointing back to timing. Everything is at 0 currently. ? Send to me.. it should run at 0 degrees. Reached out to Brian crower to validate I'm at 0 just to be sure I understood the markings as well. Has anyone ran into this before?

[@WT4T]

Non avcs cams in ej257 (avcs) heads? I'll have to double check but I think the front cam journal can't oil properly without avcs cams even when not running avcs.

[@maaaxxd372]

Haltech for 18g? Are the hybrid 2.5/2.0 really that bad to tune?

[@WT4T]

To each their own. Car was factory 16 bit and the customer wanted something cooler.

[@maaaxxd372]

@@WT4T ah haha I've always liked the carberry stuff on those especially for the price but haltech is definitely cooler

[@WT4T]

As for the hybrid issue, honestly I've tuned hundreds both before and after "chambering the heads" was a thing. They're definately more reliable with chambered heads but we didn't really have many issues prior either. Tuning wise I don't know why poeple seem ti struggle with them, possibly it's just a mental thing. Fun fact, if you're on a MAF displacement won't do much to fueling and for timing you just give the car what it wants.

[@WT4T]

I believe this customer had a hydra before carberry was a thing and he upgraded to the haltech when he swapped heads and wanted working avcs. He could have gone to jdm ECU or carberry with avcs mod but it's not what he did. I ran haltech on my car when it was a bone stock ej18, literally the first mod. Now that I'm putting it all back together it's on a fueltech (even more $$) for me it's about learning new systems.

[@doubletee4391]

@@WT4T did he have a ton of problems with the hydra? Im exhausted from trying to dial my hydra in. im looking into replacing it with a link. do you recommend that ecu for gd stis and if so can you sell me one?

[@mrphiscal]

The bug eye has a 16 bit ecu so it never had avcs. Imho

[@WT4T]

Never in the USA. JDM bugeye sti had avcs.