does anybody know how much more you can turn up the boost on the new U.S. spec EVO8. mitsu says its running 19 psi but i dought it. seems a little maxed out for that turbo. any info would be great thaks guys. THOMAS

 

i just put my boost gauge on yesterday, it hit about 18.5, take into account any line losses, and restrictive exhaust, thats your 19lbs right there. I have heard 21lbs safely on 93 octane.

 

Yeah I heard it tapers down to like 17.....I would also assume upgrading the CBV and installing a manual boost controller it would help a bit. Not sure if it suffers from a leaky CBV as in the 2nd gen eclipses. Those wouldnt hold more than 11psi. By upgrading to a metal one (1st gen)and removing the BCS restrictor I was able to get a free 2psi out of the stock set up.

 

Moving to Evo Tech...please pay attention to where you're posting new threads.

 

These aren't DSMs. The stock valve on the Evo should hold about 18 - 20 psi. I've installed a few blow off valves in evos and dont really notice a performance gain. However, one vendor in here said they got about 11HP from sticking in an aftermarket valve. That would lead me to believe, frmo their info, that the stock valve possibly leaks anything above 18lbs. RMR says from all their rally experience, and even on their 450HP evo7, the stock valve and an aftermarket valve show no difference in dyno numbers. So, it's up to you.

On 93 octane, the evo can run up to 21 psi without needing to change the fuel system. What I worry about is 4th and 5th gear where the engine runs leaner to save fuel. So far most people have had no problems with the fuel cut. I recommend running about 20 psi to be safe and not too hard on the engine. For 91 octane, i say leave it at 19 but let it go to 19 all teh way to redline....that should give a large performance increase.

Thats not even nearly maxed out for the turbo, it's said that this turbo can push up to 40-45 psi |(without vaccum offset) before it dies.

 

Running between 20 and 21 currently, on 93 octane. Manual boost controller still has some falloff (~2 pounds) by redline. Definitely pulls nice though, and no sign of any fuel cut, though I have bumped the redline... several times. Why? Because now it doesn't get soft after 5K, so its pulling still at the redline. Have to get used to 7K shifting it.

 

Hey Coolguy,

Dave Buschur originally posted that the EVO stock BOV was not holding boost above 18psi on his dyno, however, he just recently stated that it does appear to be holding at 19 to 20 psi while beating the heck out of the car on the street. He now recommends not wasting money on an aftermarket BOV unless of course you want the pssssssssssssssst... sound.

Speedlimit.......

 

That makes at least two times that I've seen that stated on this board. I ignored it the first time thinking it'd go away. There is no such thing as running leaner in high gears to save gas. Certainly not on our cars.

If you're talking about the tendency of the O2 sensor to read slightly lower in 4th gear after having just powered through 3rd, consider that the sensor is going to read lower as it heats up. The block and head and everything else is heating up too, leading to a higher tendency to detonate. But the ECU doesn't lean the thing out in 4th gear to save gas.

Thomas Dorris

 

im getting fuel cut in 4th and 5th, when I short shift from third...

Im running 21 psi with the Xede.. I think ill take my boost line off and run stock boost..

 

How do you like the Xede? Also are you running just there computer or you say you have a manual boost controler?

 

Just the Xede with Shivs new boost line/boost control thing.

I think all it does is bleed of a little boost, so your pushing more than the oem boost controller is seeing. I dont really care for it.

I dont hit fuel cut if I redline 3rd and shift into 4th and floor it. But if I short shift into 4th, (around 2500rpm maybe) then floor it, i'll hit fuel cut.

 

There are a lot of people running 20 psi without fuel cut on the evo... It seems to hit fuel cut around 22 psi if you aren't modifying the air flow signal in any way.

bryan

 

I was looking at his stage 0 deal with the cat back and the computer. Is that what you are running?

 

I made a 4th gear pass on the dyno after tuning my afc in 3rd gear and it ran .3 to .4 points richer then the tuned 3rd gear pull.

 

no Im running stage 0.5 which is Turbo-back plus the Xede's boost line which makes boost more stable and raises it to 1.5 bar.

I think in 4th, I might be pushing 1.55 bar or so though... i think thats what my prob is. My map is tuned for 92 octane and I'm running 94, so I know im not knocking...

If its not fuel cut im feeling, then the engine is misfiring at exactly 4k rpm.