Boost pressure for built engine

[ChrisD]

Originally Posted by #maverick#

Yea I was mobile and I didn't look at the dates. Honestly, I think you should get a bigger turbo. You will make more power with less boost at the expense of a little lag.

Well at least the CR is now a bit lower than it was and the new rods can handle more torque, so if I want to throw a bigger turbo on it in the future then the engine is ready for it anyway.

To be honest though I don't really want lots of lag then huge power spike when the boost kicks in - I'd rather have less lag and a bit less power. This is a car for fast road driving and doing occasional drift days in, not a dyno queen, so I couldn't really care less what the peak power output is. I just want it to be fast and fun to drive

[ChrisD]

Originally Posted by CSG Mike

Be careful with this; this comes at a very, VERY high thermal cost.

Can you elaborate?

[ChrisD]

Originally Posted by killboy

FWIW we have almost this exact same setup on our BRZ...AVO stage 3, billet wheel, race intercooler, forged internals, lower compression pistons, upgraded fuel injectors/pump, 93 octane. (no E85 around here)

Your original post asked about max boost and where it comes on, so to answer, ours is set to 14.9lbs and gets there at about 3300rpm, tapers a couple of psi near 6000 on. We make about 380whp on this one. We don't have upgraded springs though, (should have done that while in there but forgot) and I forget the CR of the pistons...try to get back with you on that. We have a built, supercharged FRS also and I get them confused.

Thanks for the info, that's nice to know how someone else is getting on with a very similar setup. I'd be interested to know what CR you're actually running if you could find out.

[killboy]

Originally Posted by ChrisD

Thanks for the info, that's nice to know how someone else is getting on with a very similar setup. I'd be interested to know what CR you're actually running if you could find out.

10:1

[ChrisD]

Originally Posted by killboy

10:1

Cheers. Exactly the same setup as me then. At least I know roughly what to expect now then. How have you found it to drive? Happy with it? Any issues?

[CSG Mike]

Originally Posted by ChrisD

Can you elaborate?

Pulling timing to reduce output, enough to function as a traction control, involves a very, very high EGT. Doing it more than momentarily (e.g. being dependent on the traction control), will result in skyrocketing temps across the board; a minor amount of that combustion heat is conducted into the engine, but it adds up quickly.

I see cats blow out all the time on the 458 cuz that's part of how the car's traction control functions, and the bursts of heat just destroy the cats. Then again there's nothing wrong with a catless 458 (except being deafeningly loud).

[#maverick#]

Originally Posted by ChrisD

Well at least the CR is now a bit lower than it was and the new rods can handle more torque, so if I want to throw a bigger turbo on it in the future then the engine is ready for it anyway.

To be honest though I don't really want lots of lag then huge power spike when the boost kicks in - I'd rather have less lag and a bit less power. This is a car for fast road driving and doing occasional drift days in, not a dyno queen, so I couldn't really care less what the peak power output is. I just want it to be fast and fun to drive

I can respect that. I have a 5858 on my car and I hit 18 lbs at about 3900 rpm stock motor though and make close to 500 hp

[#maverick#]

I have been looking into the Hyperaktive boost controller which adjusts boost based on wheel spin. Seems pretty neat.

[killboy]

Originally Posted by ChrisD

Cheers. Exactly the same setup as me then. At least I know roughly what to expect now then. How have you found it to drive? Happy with it? Any issues?

Stupid fun...thing is so stinkin' fast it's ridiculous. Running 265s and it will spin them up in 1st and 2nd on dry, 3rd and sometimes 4th in the wet. (careful, but it's so fun) I was going 60mph on the highway in the wet and gave it some juice to change lanes and it just did this sweet little power-over slide/drift into the next lane.

Only issue we are having is what appears to be a slow/sticking internal wastegate valve. After beating on it for a few miles, I start to get very slow boost response...takes several seconds to build up peak boost, as opposed to the normal instant response once above 3k rpm. Started happening about a month after install, and had the kit for about 2 months now.

Turbo is coming out next week for inspection, and we'll decide how to proceed from there, but I have been leaning toward going to external wastegate setup anyway, so I'm pretty sure we're going to do that either way.

[FRS Justin]

Originally Posted by #maverick#

I have been looking into the Hyperaktive boost controller which adjusts boost based on wheel spin. Seems pretty neat.

AMS 2000 is rock solid

[#maverick#]

Originally Posted by FRS Justin

AMS 2000 is rock solid

Yea another rock solid boost controller. Both of these are for people who know what they are doing and want the most out of their car!

[ChrisD]

Originally Posted by #maverick#

I can respect that. I have a 5858 on my car and I hit 18 lbs at about 3900 rpm stock motor though and make close to 500 hp

is that on E85 or normal unleaded?

[ChrisD]

Originally Posted by killboy

Turbo is coming out next week for inspection, and we'll decide how to proceed from there, but I have been leaning toward going to external wastegate setup anyway, so I'm pretty sure we're going to do that either way.

What's making you want to go external wastegate (if you weren't having the problems with the AVO one) ? Funnily enough I did have an issue with the wastegate on my AVO turbo too... hasn't quite been resolved yet so I'm not sure exactly what the problem is.

[Matt@Cosworth]

I'd say you're going to struggle to flow enough through an integral wastegate for anything over 400Bhp on a single turbo


obviously this depends on what level you're happy the 'base' boost level is at
if you can't get any less than 0.5 bar of boost then some people like that