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View Full Version : Safe boost pressures on stock motor???



t_mac
10-20-2010, 02:30 AM
hi just curious just got a manual boost controller and the hks FCD is on the way anyone know wat a safe boost to run is. My friend owns an MR2 and hes been running 15 for well over a year just curious on ur thoughts on safe boost pressure. Thanx

Hookecho
10-20-2010, 02:51 AM
With my ST185 engine with TMIC I run 14lbs with no problems.

DudeMan
10-20-2010, 03:01 AM
15-16 pounds is the most I'd run on a stock motor with a stock 26.

Which is what I used to run and what I'm planning to run once its back on the road.

Run high octane fuel and maybe get a step colder spark plugs for insurance.

Nitro_Alltrac
10-20-2010, 03:15 AM
I'm running 13 on mine without issue. Like Dudeman said, 15-16 is probably the most you're going want to run on the stock CT26. That's about the top end of the effiency range for the 26.

bzdweezy
10-20-2010, 03:21 AM
No more than 16 pounds if this is a 3sgte

Mafix
10-20-2010, 04:31 PM
it all depends on the setup. stock 185 i assume?

v8killer
11-03-2010, 08:48 AM
stock engines 17. i did this for a hella long time and i did abuse it and also take care of it lol cant see more than 15 doing anything on the st185 ic though. but yeah i am sure if my gen1 3sgte with 120k can do it so can any other.

wilmatic
12-02-2010, 01:18 AM
what mods need to be done on a stock st185 to get 14-16 pd boost? thanks

Nitro_Alltrac
12-02-2010, 02:56 AM
^Boost controller and a real boost gauge.. I've got a manual controller on mine. I carefully dialed the boost up to where I wanted it. You want a real gauge though and not that crap thing that comes stock. You need to be able to see what you're actually running. You also want to make sure you're engine is in good shape and you maintenance has been done. If it got anything wrong with it now, cranking the boost up is going to make if VERY apparent very fast.

Facime
12-02-2010, 03:06 AM
I would also build a tunable boost cut defender (http://www.alltrac.net/mods/fuelcut.htm) so you can dial up your cut to just over the boost level you decide on. Im running 14lbs on stock internals/fuel system with my BCD set for 17lbs.

wilmatic
12-02-2010, 10:51 PM
cool, thanks

rizin
12-13-2010, 05:53 AM
Facime thanks for the link about the adjustable fuel cut defender.

ChrisD
12-14-2010, 05:36 PM
14-15psi assuming good health of the motor. Also, I would be careful to watch any knock response / hesitation / bucking as you increase. Do it in increments until you are satisfied with performance.

ericfragola
01-07-2011, 04:20 AM
^Boost controller and a real boost gauge.. I've got a manual controller on mine. I carefully dialed the boost up to where I wanted it. You want a real gauge though and not that crap thing that comes stock. You need to be able to see what you're actually running. You also want to make sure you're engine is in good shape and you maintenance has been done. If it got anything wrong with it now, cranking the boost up is going to make if VERY apparent very fast.

just curious to know everyones opinions on MBCs. i know you can make your own, as well as buy one just as cheaply on ebay. but is there really a difference between a cheap MBC and an "expensive" one? im just curious to know what everyones opinion is on one before i order. or if there are any suggestions. because a buddy of mine got one pretty cheaply off ebay i believe and all he got extra was 2lbs of boost. i want to be able to actually up mine to the 15-16 range. also, any good boost gauge reccomendations?:) ive got 2 spares but they dont work -_-

ChrisD
01-07-2011, 05:20 AM
twosrus.com has an excellent manual boost controller, that would be my recommendation. $50 and you get good hoses to use, 3sgte specific instructions, and it's proven to work. There are a couple of different types, some built better than others, but essentially they mostly do the same thing. I use MBC's on both of my cars.

ericfragola
01-07-2011, 05:30 AM
i give you a gold star for a great answer chris lol. just what i was looking to hear. ill go ahead and order a twosrus mbc now :) my main concern was that it actually works. unlike my buddy who only was able to add 2lbs.

Facime
01-07-2011, 06:59 AM
Your buddies controller probably needs a tighter spring. That can possibly be accomplished by taking the device apart and stretching the spring making it slightly longer.

I bought one off ebay and was having a wierd (and later discovered unrelated) issue with boost spikes so I ended up building my own for about $20 in hardware and it works perfectly. All of the manual boost controllers use one of two principals to function and beyond that the differences are mostly cosmetic.