MikeDizz

Picked up my first Evo 8 recently. Mods are
Fully built 2.0 bottom end
S3 cams
Gsc valves springs retainers
FP race cast manifold
AGT 64mm turbo
Radium fuel rail/pressure regulator
e85
+ other supporting mods

Finally got the car properly tuned, made 640whp which is great for me but full boost hits at 6k revving out to 8500. Some people are saying it's the turbo, others are saying it's the s3 cams? I'd like to figure out a setup that will yield me around 650whp but get closer to 4500rpm full boost. All input is greatly appreciated.

schuhie

I don't have experience with the AGT turbo or the S3s but I would say that both of those are contributing to the lag.
That turbo is larger than FP Black and I run a red and see full boost with S2s around 4500rpm.

Switching cams would probably help a bit but honestly to get down to that 4500rpm number, will likely require a turbo change.

Evo9isLife

Sounds like the turbo is using the AGT open scroll turbine housing which would explain the lag. If thats the case I would contact AGT to get their MHI twin scroll housing to improve spool and response. You will sacrifice top end power though.

schuhie

This is a good point, I didn't realize they offered both options. If it is the open scroll housing, that would be a part of the issue as well.

I still think that even with the twin scroll housing, it will be hard to hit the desired boost threshold but probably worth trying assuming that's a straight swap. Way cheaper and easier than swapping turbos and cams.

MikeDizz

it is the twin scroll journal bearing

sunnysideup

What gear and what rpm do you go wide open throttle?

MikeDizz

3rd gear 3000rpm

sunnysideup

Could it be that the boost was ramped in a bit slower on the tune?

Also regarding your goals, I think full boost in 3rd at 4.5k at 650hp will be pretty hard to achieve. Even in forth it would probably only spool ~500rpm faster. Only way I see you spooling faster would be to have MIVEC, more displacement and a faster spooling turbo.

MikeDizz

I dont think so, tuner is well seasoned and wouldve told me if he could squeeze more out of it. I was looking into the g30-660 kit which seems to be the way to go for faster spool, plus a set of s2 cams to give me slightly more down low but looking for other input before I do

sunnysideup

You won’t be making 650whp on the g30-660. You’d need something bigger.

xxthayxx

iTrader: (11)

Got a recent WOT pull log you can attach?

MikeDizz

When I get home I'll scan the sheet

jagboy125

On fp black ball bearing mhi with kelford 272 cams I am seeing full boost around 4200 rpm made 460whp on pump and 550whp on e85 on a mustang dyno. maybe fp black and s2 cams would probably fit your needs

MikeDizz

yea my tuner was showing me a few cars with the same setup as you, made 600 wheel and spooled at 4500.

SnailSpeed

iTrader: (6)

I haven’t posted my review yet but on my evo 8 with a stock bottom end, stock intake manifold, stock TB, s2 cams I see full boost in third at approximately 4300 rpm on the AGT 62mm mhi hotside with the dual port internal gate actuator controlled by a 3 port ebcs tuned by me.

Initially I was seeing full boost at around 4800 and felt pretty lazy but once I fine tuned my wastegate duty tables I saw a huge improvement.

By full boost I mean 27psi and it makes 300wtq right at 4k rpm and this is third gear of course starting the pull at 2500rpm, also I must mention I know I have a decent sized boost leak that I haven’t fixed yet.

In the single scroll AGT 64mm bolt on option from what I have seen it tends to have full boost at 5500 on a 2.0. But the twin scroll is usually in the 4800rpm range.

if possible post your wastegate duty cycle tables, also what kind of wastegate actuator are you running and is it preloaded correctly?