hifd

My Map 2.4 standard rod, Cbrd bbk-b with meth water injection made 523 hp and 467 lb feet. Boost spiked to 31 at 4500 rpm but dropped quickly to 27 for most of the run. My mechanic said it would not hold higher boost. I am not sure if there is a problem limiting higher boost.

Anyone with the bbk-b with similar problems? I haven't seen too many recent graphs, just the beta version ones that led me to get this turbo.

tscompusa

iTrader: (31)

if you're using a mbc you can switch it to a 3 port and make it hold more boost at higher RPM.

the first thing to look at though would be the preload on the wastegate actuator or the actuator in general. if you used a stock wastegate, you could switch to something like a 26psi turbosmart actuator and it would hold boost much better.

hifd

Boost pressure is solenoid controlled by the AEM.
I'm running the Forge wastegate I believe it has a 24 lb spring. My mechanic said he set the preload at a high level.

Thanks for the help.

David.

tscompusa

iTrader: (31)

it either needs more duty cycle or the wastegate actuator spring is not keeping the flapper shut.

or the turbo is running out of breath uptop due to the displacement.

94AWDcoupe

iTrader: (125)

its a 57lb per minute turbo. its not gonna hold 31. do you have the optional ported cover? are getting any surge? what compression you running?

rick1024

iTrader: (7)

if its the map 2.4 then theres a good possibility he has 10.5 comp ratio

hifd

I have the ported turbo. Compression ratio is 9.7.
It's a fun daily driver for now, I am tempted by all the graphs of
the FP black bb though.

Drifting Away

iTrader: (6)

Because who needs more power than this on a street car....lol nice number man.

Abacus

iTrader: (9)

Not a bad idea to run a backpressure sensor. With a 2.4 and 57lb a min turbo its being choked out on the top. Its hard on the exh valves and may lead to a burned/bent one.
Have you thought of going with a GTX3576 or 6262/6466? You have enough displacement where spool will still be ok and it won't taper.

hifd

The Pte and Garrett turbos will necessitate a new exhaust manifold, plumbing etc. so sticking with stock frame choices are better for me. Like many with more money than brains I have a hard time controlling the urge to buy something new just for the sake of having something new. The wife hasn't enrolled me in a 12 step program yet but no need to push the limit.

94AWDcoupe

iTrader: (125)

I wouldnt have an urge to make any changes. thats a really nice powerband there. it falls past 7500 but so what. it makes great power from 4000-7500. thats a meaty powerband. plus these cars just plain become money pits past 600whp. get greedy for power and be sorry you did or enjoy what you have if you ask me.

rick1024

iTrader: (7)

I have the gtx3582. I'm not sure the difference between the 82 and the 76, mine spools around 3750 and builds to max boost very very quickly. That being said I sometimes wish it would spool sooner. I have a 2.4 built by Evo dynamics using the map stage 2 motor. I also have gsc 280's and 1250 fic blue max. I put down 601 on a notoriously low reading mustang (as I'm told by everyone who has run on it lol). My plan is to get bigger injectors and install my arp l19's, and retune it to clean up the pump gas map. To be honest 601 is hard enough to control as it is, I have decent tires on the car and they break loose when you slam the gas. I want to get a shep t/c and tranny and finish some other little things in the suspension, get some new rims and call it a day. I am happy with it, it's incredibly fast.

Biggy VIII

That post should be added to "Sticky:" as a dedicated closed thread.