Safe PSI to run boost?

[deviantek]

Based on the specs of my car, what is a safe boost psi to run for a weekend rally-crosser? PSI is currently set to 17-18 using a Turbotech Boost Controller.

My car specs: (cut & paste)

Lancer Evolution GSR CD-9A (October, 1992)
Engine
* Rebuild by ALEX 3,000Km (1,875mile) ago
- Mitsubishi piston rings, thrust bearings, main bearings, front & rear main seal
- Mitsubishi Evo new turbo
- Power Enterprise 1.5mm metal head gasket
- Power Enterprise timing belt and balance belt
- Rally Art engine mounts
* NGK racing spark plugs
* NGK racing spark cables
Transmission
* Rebuild by ALEX 4,000Km (2,500mile) ago
- Mitsubishi ALL new bearings, synchro-mesh rings
Suspension
* Replace stabilizer and lower arms from CD9A (Evo 1) to CE9A (Evo 2, 3)
* KYB Rally / Gravel springs
- Front: 4.2kg/mm
- Rear: 3.5kg/mm
* KYB Gravel shock
- Front: Rally Special
- Rear: Rally Special
* Rally Art suspension upper mount bushings
* Rally Art front tower bar
* Rally Art rear tower bar
* Cusco Type 2 lower arm bar
* Jspeed (Car Station Marche) fender brace
* Cusco Zero-2E coilovers w/ Cusco Econ (installed)
Differential Gear
* LSD with ALEX custom setting
- Front: Cusco LSD RS 1 way 4,000Km (2,500mile) ago
- Rear: Cusco LSD MZ 1 way 3,500Km (2,188mile) ago
* Evo RS front LSD conversion parts
* Evo RS rear LSD conversion parts
Exhaust system & Air cleaner
* Fujitsubo RM-01A Exhaust system
* Fujitsubo racing down pipe
* After market stiff muffler bushings
* M's air cleaner
Clutch
* Cusco Hyper clutch cover
* Cusco Hyper light weight metal clutch disc
* OS Giken light weight fly wheel
* Knight Sports stainless steel mesh clutch hose
* Mitsubishi new clutch master cylinder
* ALEX stiff clutch pedal bracket
Brakes
* Brake pad
- Front: Delphi Lockheed ZR (for racing track)
- Rear: Delphi Lockheed MT (for Rally and Auto-X)
* Brake calipers Rebuild by ALEX 3,000Km (1,875mile) ago
* ALEX brake piston position helper springs (inside of the front brake calipers)
* APP stainless steel mesh brake hoses
* Cusco brake master cylinder stopper
* Mitsubishi new hubs and knuckles
For Rally
* SAFTY21 (Cusco) 14 points CDS roll cage with
SAFTY21 roll cage sleeve (order made)
* SAFTY21 (Cusco) A and B pillar reinforcement plates
* Carrosser (Cusco) front skip plate
* Carrosser (Cusco) gas tank guard
* Carrosser (Cusco) differential gear box guard
* Carrosser (Cusco) Rally mud flaps
Interior
* Driver side
- SPARCO Corsa 2000 model black seat
- LaStrada Rally Super Low position seat rail
- Sabelt racing seat belt (3 inch / including shoulder pads)
- Carrosser (Cusco) Rally foot rest
- ALEX custom eye ball mounts for 4 points seat belts
* Passenger side
- SPARCO Evo2 2004 model black seat
- LaStrada Rally Super Low position seat rail
- Sabelt racing seat belt (2 inch / including shoulder pads)
- Carrosser (Cusco) Rally foot rest
- ALEX custom eye ball mounts for 4 points seat belts
* OMP Velocita 35cm black suede leather steering wheel
* Rally Art manual shifter bushing
* RAZO WRC style shift knob
* Rigid Alpha break and clutch pedal covers
* AC, CD, speakers, radio units and floor cover are removed
* Blitz turbo timer
Others
* Mine's 'race tune' ECU
* YOKOHAMA ADVAN A035 (195/65 R15) tires (rally setup)
* 5Zigen FN01R-C 17x8 wheels with Falken Azenis RT615 225/45R17 tires
* Mitsubishi Lancer Evolution 3 stock OZ white wheel (rally setup)
* Power Enterprise MAG Power 2 oil filter
* Aftermarket Rainguards
* Mitsubishi fuel filter 500Km (313mile) ago
* Mitsubishi cam shaft position sensor 600Km (375mile) ago
* Red Line engine, transmission, T-case and LSD oil (10w40, WD-90, & Heavy Shock)
* Evo 8 MR BOV (crushed for increased boost pressure)
* ASI 50mm Aluminum Race Radiator + ASI Hoses
* SuperPro Rear Control arm, Trailing Arm & Rear Sway Bushes
* Rear Control arm reinforcement plate (by Speedware)

 

[olly]

the psi you're running now is fine

 

[Dean]

yeh, wouldnt go anymore than that.
even though the cars been rebuilt, it looks to be a standard rebuild.
by the looks of it you havnt gone forged rods and pistons.
these are the main factors you need to consider when upping the boost

 

[EVO85]

You know 90% of what you have posted has no relevance to the question that you pose I'm assuming that the turbo you are using is a standard small 16g? If you raise the boost much more, it'll be beyond the threshold where the turbo is most efficient. I'd say if you were using it regularly for competition, the bare minimum would be forged pistons at 18psi and beyond...unless re-building engines is one of your favourite past-times!

 

[GSR94T]

id feel safe daily on 17-18psi on the standard internals for a 16G

 

[deviantek]

You know 90% of what you have posted has no relevance to the question that you pose I'm assuming that the turbo you are using is a standard small 16g? If you raise the boost much more, it'll be beyond the threshold where the turbo is most efficient. I'd say if you were using it regularly for competition, the bare minimum would be forged pistons at 18psi and beyond...unless re-building engines is one of your favourite past-times!

Sorry, I realize 90% was irrelevant, but was just doing a quick cust&paste of my spec sheeet.

With that said, it's actualy a rebuilt evo 3 engine running a big 16g.

 

[WindeX]

Hmmmm, I have gotten all kinds of different responses about E3 engines and upping the boost. Because they have a higher CR than ther earlier 4G63s some say its not safe to go over the stock pressure, but I dont believe them. Maybe do a search on EvoOz.

 

[VR-4Squid]

The only real way to know what's safe is to get a datalogger so you can monitor knock - if there's no knock, it'll be fine.
Boost doesn't kill engines, running too much ignition advance for the amount of fuel does.

I'd recommend throwing the mines ecu in the bin and getting a stock ecu custom chipped (or an aftermarket ecu). The mines ecu is a "one size fits most" band aid solution to tuning, just adding more fuel and ignition timing - at best it will never run as well as it could, and at worst it'll cost you an engine - my ex-flatmate found this out the hard way with his skyline.

 

[Kane_GSR]

off topic but how much if any boost spike do you get with the turbotech?

also stock 4g93t with vr4 tdo5/exhaust is 12-13psi reasonable?

 

[Liberoz]

off topic but how much if any boost spike do you get with the turbotech?

also stock 4g93t with vr4 tdo5/exhaust is 12-13psi reasonable?

Should be OK just don't get into a habit of running over 15psi

 

[Dean]

off topic but how much if any boost spike do you get with the turbotech?

also stock 4g93t with vr4 tdo5/exhaust is 12-13psi reasonable?

fine mate,
exactly what i've got. Get a high low boost controller or something, run 7-8psi on a daily basis, then run 14-15psi when you wanna play.

 

[WADADLIG_EVO]

Does any one know if the stock E3 ECU has a boost cut limit in it? Or fuel cut dependent on boost?

I have searched but not really finding any answers.

WADAD

 

[WADADLIG_EVO]

Found that the cars do boost cut but what is the Evo 3 psi limit? anyone?

 

[Liberoz]

Chipping the oem ecu and removing the boost cut in the flash is what you want to be doing.

 

[WADADLIG_EVO]

The reason I am asking is I think I hit boost cut the other night but the boost gauge I have seems to be sticking the needle at 15psi. I had turned up my MBC, but the car was hesitating like crazy so I started to turn it back down. The strange thing is the car seemed to get faster and faster as I dialed the MBC back however it is still only registering 15psi. I wonder if I had turned way past 15 and reached this boost cut limit, what ever it is?

 

[Liberoz]

The reason I am asking is I think I hit boost cut the other night but the boost gauge I have seems to be sticking the needle at 15psi. I had turned up my MBC, but the car was hesitating like crazy so I started to turn it back down. The strange thing is the car seemed to get faster and faster as I dialled the MBC back however it is still only registering 15psi. I wonder if I had turned way past 15 and reached this boost cut limit, what ever it is?

Hahahhaaa Mitsu made this feature to protect people like you from damaging there engines if you were logging it just go up on the boost until it starts increasing the knock count, then back it off till it doesnt knock or no more than 2-3 counts max and thats were you should be able to just put your foot down and enjoy it safety, rather than break it.

:lol: at the low boost settingmensioned above.... my low boost setting is 16psi :w00t: pays to have a fully built motor so you can really enjoy what lies within a built 63

 

[WADADLIG_EVO]

The motor is full built and is probably why I am able to ask what the boost cut is cause the car was behaving like a Beast!!!! The previous owner said it ran 20psi on pump but I have never or was never going to take it there.

If the car was now experiencing boost cut then I think I took it way beyond that. Not sure though. No one seems to believe what I was describing but one thing is for sure the car is still only registering 15PSI on the boost gauge and I turned the MBC down at least 15 half turns.

I know I am Newb but I am just trying to figure out what is happening.

WADAD

 

[ENGINR]

I'm running the EVO3 compression ratio (9:1) and pumping 19psi through my built engine.

At the end of the day mate it will come down to the fuel you use and how the engine's been tuned.

 

[Liberoz]

I was about to post that ENGINR what ron fuel are you useing?

If it hasnt been tuned for your particular Ron fuel! it would be pinging its head off and knocking resulting in slug power on the oem factory fuel settings from japan is 101 ron, being in ANTIGUA you might only have access to 92 or 95 ron which would make a hell of a difference.

Dare I say your ecu needs to be tuned to what ron fuel your able to get and whilst your there get the boost cut removed from the bin file.

 

[JAP63]

Does any one know if the stock E3 ECU has a boost cut limit in it? Or fuel cut dependent on boost?

I have searched but not really finding any answers.

WADAD

Mine doesnt seem to have one....one day the boost controller stepper motor jammed and let in 2 bar of pressure and it didnt hit a cut at all, mind u ,I backed off before the air had been used by the engine, ie the wastegate hadnt opened and the motor wasnt flowing and making power, if i didnt, i predict the motor wouldve lasted about 3 seconds on full noise.

Hmmmm, I have gotten all kinds of different responses about E3 engines and upping the boost. Because they have a higher CR than ther earlier 4G63s some say its not safe to go over the stock pressure, but I dont believe them. Maybe do a search on EvoOz.

Be the first to run 18 pound+ and let me know how long it lasts...I dont put mine over 14 pound

14 pound in the E3 motor is 19 pound in a VR4/Early evo motor...And for another thought, try taking the thick rods out of a VR4 and put skinny 7 bolt evo ones in it and see what 19 pound does to it...

Yes the E3 motor will tolerate higher boost pressures..but for how long? and what goes first? where not talking about the tune here, but the physical strength of the internal components, they thinned everything down to enable less rotational mass and inertia, ie...quicker boost response and overall faster rev up...but it comes with a cost ofcourse, less strength....Another point, someone I know consistently replaced headgeaskets on their E3 track car when boost levels of 14-17 psi were used, the car had the ass driven off it, in stockish trim tooo... but my point is, this boost was popping things...alot.

The most unfortunate thing is . the Big 16G loves 14-20 pound, but its not really possible..unless you want to "see" what happens...:unsure:
Or alternately, forge it first, rods and pistons is all it would need.