am i overboosting

[RideNslidE]

so i just got my 240 running and driving again heres my setup

t288:1 fmu SMICwalbro pumpdistibutor retarded 2 degreesvery simple right

i just got myself the AEM tru boost gauge/controller i wanted to increase throttle response by setting my crack pressure higher and keeping my overall psi the same. i set the crack at 4.2 psi and the duty cycle at 10% which should put my max boost just above 5 psi then the wastgate should take over open around 7.5 psi.

its got a little alarm thing so i set the alarm for 9 psi and aparently it jumped to allmost 10psi for a short time so i turned it off to monitor just the wastegate. the psi very eratic and jumps around from 8.1 to 9.4 with or w/o the controller on.

my question is how bad is this? and how can i fix it?if it is not that bad to hit 10psi with just a fmu let me know, has anyone done this reliably?

[WDRacing]

Its hard to not have boost creep when you run a small turbo in a larger displacement engine. The KA should really never use anything under a T3, the T2 flange just can't flow enough and it creates boost creep issues.

I dunno how your controller works, but it sounds really complicated for something that should just increase the boost.

I'd hook the wastegate actuator to the vacuum line and remove the controller. Then check to see if it spikes. If it spikes there are a few things you can try. Porting the hole behind the wastegate flapper chingus to just about the same size as the flapper chingus itself is always a good idea.

10 psi isn't wicked high, but if you're using the stock fuel pump I'd worry about it going lean. 10 psi at 8:1 is right around 125 psi of fuel pressure...that's to much for a stock unit to handle.

WD

[WDRacing]

NM, I see you've got the Walbro. Still, 125 psi is more then a 255lph pump is rated for...by alot. I was going to run 10-12 psi. But I was going to use a 4:1 FMU and twin pumps.

DO as I suggested anc check for boost creep. Also, as a safety only thing, wire up an overboost switch, real easy to do and there's a how-to right in the FAQ. IIRC it's called Cory's Overboost Protection.

WD

[biggie]

See the Walbro, but no mention of injectors, have to assume they aren't stock though.

The management you are using would have me scared. I can't recommend running over 5-7psi without some good ECU/standalone type management.

[WDRacing]

He's using a 8:1 FMU. Can't use one of those with larger injectors

[biggie]

He's using a 8:1 FMU. Can't use one of those with larger injectors

Ah, don't know much about FMUs. But no way the 270s can be pushing enough fuel for 10psi can it?

[RideNslidE]

what do you guys think about adding snow perfomance or AEM's water/meth injection system and me turning up the boost to 12 psi.

i dont think the WG will creep past 12 psi. and it should make my setup safe at that level of boost, correct me if im wrong.

I know you said dont use this stuff as a band-aid but i obviously wanted to increase boost anyways and i think it will solve this problem. (am i a retard?)

my goal was 260hp to the wheels which i need about 12psi for. im getting my wideband in a couple days so ill know right where my afr's are at and im going down to do the quarter mile in a month or so im hoping for a 13.5 or better, is that possible.

hey WD it seems like you were in the air force what was your AFSC im a 9S100 Technical applications specialist.

[KFL]

Your supposed to setup the aem truboost to about the wastegate spring pressure. Since its 7psi(stock I think t28 right) set it for 7/7.5psi.(lower slightly from there if you experience some overboost) Putting it lower will cause turbo to spool slower.

[RideNslidE]

i realise that, i really didnt want it to spike. i set the crack pressure to 4.2 because thats about 3psi less than i wanted the boost to go to. when i increase the boost to 12 psi i'll set the crack pressure to 9psi to be safe.

[KFL]

i realise that, i really didnt want it to spike. i set the crack pressure to 4.2 because thats about 3psi less than i wanted the boost to go to. when i increase the boost to 12 psi i'll set the crack pressure to 9psi to be safe.

Gotcha it shouldn't really spike that much, and the alarm will cut off boost if it spikes. I run 11/14psi and have had it hit 18psi alarm cut boost at 16psi. You should set crack pressure to whatever wastegate is set up for and just adjust duty cycle.

I'm running jgs turbo kit,tial 38mm wasetgate 7.5psi spring. I set crack to 5 and felt the turbo slow spooler, then set it to 7.x and it felt much better. I'd look into a tuned ecu or at least retard your timing a bit more. 2degrees is a tad aggressive. My buddies t25's tuned ecu's run like 4degrees at 7,8psi. I'd rather be safe than sorry on stock block.

[RideNslidE]

ya you right i may retard the timing a little more just incase i run out of water when im boosting. i am going the cheap way for now so a tuned ecu is out and when i do get one i may go with the AEM ems.

once i get my water meth injection set up i should be fine at 12 psi. authough i have been wrong b4. if i blow somthing up, not that i want to but it would give me a reason to build up my block.

[DMan II-40]

interested in the water injection question

[WDRacing]

Sorry fella's...got busy over the holidays. Lets see if I can cover everything I missed in one post.

Ah, don't know much about FMUs. But no way the 270s can be pushing enough fuel for 10psi can it?

The FMU is going to add 8 psi of fuel pressure for every 1 psi of boost. So it can add the fuel, but you're going to be running a ton of fuel pressure to do it. Most consider 8 psi the max for a fmu application. You also have to worry about ignition retard. Done by retarding the base timing or some type of aftermarket timing controller like the MSD BTM.

what do you guys think about adding snow perfomance or AEM's water/meth injection system and me turning up the boost to 12 psi.

i dont think the WG will creep past 12 psi. and it should make my setup safe at that level of boost, correct me if im wrong.

I know you said dont use this stuff as a band-aid but i obviously wanted to increase boost anyways and i think it will solve this problem. (am i a retard?)

my goal was 260hp to the wheels which i need about 12psi for. im getting my wideband in a couple days so ill know right where my afr's are at and im going down to do the quarter mile in a month or so im hoping for a 13.5 or better, is that possible.

hey WD it seems like you were in the air force what was your AFSC im a 9S100 Technical applications specialist.

Water/Alky injection is an excellent way to add fuel and kill knock. I'm a huge fan of alky injection. However, if you run 12 psi you're FMU is cranking the fuel pressure up high enough to crack a fuel injector and that's without a boost spike. Not to mention you're fuel pump can't support that much pressure etc etc. The FMU is an awesome low boost management item for a low boost setup. But that's it...

I was a 2A572, Helicopter Crew Chief. I spent the majority of my career fixing and flying on the MH53J Pavelow and the H60 Pavehawk

EFI Specialists Rom tunes are only $350. If you wanna run more then 8 psi, that's really the way you'll want to go. OR use the hacked MAF and some 370's. Then you can use the alky injection to add more fuel when the 370's max out. You'll need a dual stage boost controller IMO. If this interests you, I can explain further.

WD