Max safe boost? [Merged 10-6]

[Turbolaser]

Is it safe to do the boost contol solenoid mod on a stock 1G?

 

[kaslasma]

The Datalogger is a must. That way you know if you are knocking or not. Hardwire the 190, and depending on the efficiency of your FMIC you might be able to go up to 17 psi. A fuel controller would allow you to add or subtract fuel in various rpms to increase performance, however, you could get a fuel pressure regulator and turn your base pressure up and that would "increase" your injector output <putting more fuel in> and allowing you to turn the boost up. Infact, turning the fuel pressure up is a common way other car groups I have seen start their fuel tuning. There are various other methods to do this but with what you are looking to do I believe it will work.

 

[Boosted19]

sorry for the misunderstanding kalasma... i havent run 11's but i no people have... sorry for the confusion!!! oh and i aslo had a logger!!!

 

[Generation1JeY]

alright where can i get the cheapest datalogger that will get the job done? i know that for the harness u just go to that one datalogging website, but what kind of pda do u have to get for it to be compatible?

 

[kaslasma]

There are several different logging options. First would you like to go the PDA route or the Laptop route? Do you have a laptop? If so i'd suggest that one. I use a laptop mainly becuase I already had one and I liked it better than the palm but thats my personal opinion. With my laptop I use software from a company TMO. The <a href="http://www.pocketlogger.com/index.php?pid=faq_pda_comp">PocketLOGGER</a> site has a listing of capatiable palms. They sell the software and a cable. If you decide to go the super cheap <still works just fine and you save money> there are free software and there are instructions on how to make a cable. There are more out there but to start out I would do one of those.

 

[Boosted19]

i have a palm m100 with the mmcd software. works great. the only thing i dont have is the cable to connect to the obd1 port... make me an offer if you want it... [email protected]

 

[flyinhawaiin]

I was just wonderin what is the highest/safest boost level you can get out of a 2G motor/turbo.

 

[RBurroughs]

16psi

 

[SnowWhite]

I truly believe with the right supporting mods you can definately run quite a bit more boost than 16 lbs on a stock engine.

 

[rdeterman]

i think what he ment was on the stock motor/turbo combo

 

[dsmpride]

The stock T25 on the 2gens have trouble holding anything higher than about a bar of boost to redline. Plus the SMIC, fuel system, injectors, and bypass valve can't handle anymore than that either. In fact the stock bypass valve can't hold very much more than stock pressure. The only upgrade that is really 'required' for higher boost is a BOV. Then I say 14.7 psi is the max with everything else stock.

Kent

 

[flyinhawaiin]

THANKS ALOT GUY I APPRESIATE THE HELP

 

[leakyfaucet]

Usually with the stock CBV you can't get more than 12psi anyways.

 

[Thomas91169]

nope the stock cbv/bov will leak or bleed anything past 12psi. that should be your first mod, getting a better cbv/bov. then go with a K&N intake kit and a 3" catback exhaust and you could see a constant boost of about 13psi, and a spike of 16 before 5.5k rpm's. the stock 2g turbo putters out at 5.5k thus why it drops off.

but on a stock fuel system its ok to run 15lbs. any more and you will need to add more fuel and tune.

 

[91Bomb]

Have a few questions on the 13g performance and the 1g A/T car.

What is a safe boost level for the 13g? < 390 injectors, 2.5" dp, k+n >

When does the 13g reach its ideal efficiency range before it just starts pushing 'hot air' into the engine and nothing more is gained in terms of performance and bad things start to happen?

And on the 1g A/T cars how much boost is ok before you run into a lean condition and/or fuel cut? < I've been reading for a long time now about how the M/T cars are safe to 14lbs before risking trouble so with the smaller injectors the 'safe' boost level has to be lower, right?

I might be getting my engine rebuilt soon and will be installing a real boost boost gauge and mbc and was planning on running 12-12.5 lbs boost using 93 octane. I'm going to have the turbo solenoid in use so ?I don't have to worry about knock because it'll provide a failsafe by limiting boost should it occur? and if the o2 sensor detects a lean condition it retards the timing, right? SO, with these two nifty items in place and properly working I shouldn't have to worry about damaging my nice rebuilt engine?? < and of course limiting boost to 12.5lbs >

If I use the 8.5:1 pistons will the injectors lean out sooner and should I be thinking of keeping the boost level a little lower than if I stick with the 7.8:1's?

Like I mentioned, a real boost gauge will be used but I really don't want to bother with an egt and a/f gauges at this point while running a modest setup. However, if I decide down the road to swap the turbo to a 14b or 16g then those gauges would go in as boost levels would be increased.

Thanks in advance, Greg

 

[kyledykstra]

If you're rebuilding the engine, pick up a 14b for cheap while it's out. I've driven stock A/T cars, and I have a mostly stock A/T '93, cept I have a 14b, manual cams, and 450's. (all stuff from my '90). Makes a big difference from the stock one I drove.

On another note, I'd bother with an EGT gauge while you have a modest setup. You'll probably get more power and speed out of being able to tune a modest setupi, than buying parts and not being able to set them up right.


Also, by turbo solenoid are you talking about the stock Boost Control Solenoid? How are you going to run that in parallel with the MBC?

 

[91Bomb]

Right now I'd rather use my 13g at 12-12.5 lbs for several reasons. With a 14b (or 16g) I would only be running 14lbs max BY CHOICE anyway and since that's only 1.5- 2lbs more I'd rather stick with the faster spool-up of the 13g < plus the m/t cams hurt the low end too > and I don't have to get the '95 ex. man., 450 injectors, cams, and ecu.

I don't have any tuning equipment so I haven't or wasn't planning on tuning the car.

About the boost control solenoid -- I was planning on installing a bleeder valve near the waste gate actuator so I understand if the knock sensor tells the BCS to limit boost it won't be knocked down to 7lbs like if I didn't have a bleeder valve but it would still cut the boost noticeably down from 12lbs and I would see that and have things checked out if that was to happen.

Like I said I want to keep things simple right now and mainly what I need to know is if 12.5lbs is well within the capabilties of the 390's and in the efficiency range of the 13g? (stock boost is 9.9lbs?? so 2-2.5lbs over should be ok even with 8.5 pistons but I want to make sure)

-Greg

 

[Awoler]

get a data logger first if your that worried about it the 13b is a nice torqey little turbo but you want make any real power. re wire your fuel pump too. use the logger and and up the boost till you just start to get knock in a full run through 3rd meaning 1st no knock 2nd no knock 3rd maybe 1-8 counts on the data logger and that soloniod wont really protect you from sh*t forget that soloniod it would probly be such a resriction of you put the boost controller in wrong you could blow the turbo or maybe your engine! buy a pocketlogger first so you know what is happening first then start trying to sqeeze what you can out of it

 

[byebyev8]

right now on my 13g I've been running between 14 and 15psi and its been holding up good wouldn't recomed runing more than 15psi on the 13g becuase its gonna be blowing hot air.

 

[91Bomb]

Are you getting any fedback from a datalogger/egt/a/f sources? If so, how does everthing look?

I was looking at the map on the 13g awhile back and to me it appeared that at about 12-1/12 lbs the 'efficiency rate' drops off big time. I really don't know what that exactly indicates but the sharp dip on the map I seen is why I would be looking to spike at about 13 lbs with boost creep and settle back down to around 12 lbs.

The other worry I have is that on the 5-spds it's generally accepted that 14 lbs is safe with the 450 injectors and after that you're risking a lean condition -- so the 390's have to lean out sooner than the 450's, right?

I wish I knew for sure at what boost level the 13g peaks so I can set it so that 1) It's not pushing hot air and 2) it's not spinning faster than its mechanical ability and burn out prematurely.

Now, if I knew I for sure that 14 lbs didn't cause any of the above of course that's where i'd set it.

But here's a question, what if 14 or 15 lbs was known as FACT to be within the 13g's 'safe' range but at these boost levels you seen that you were starting to lean out and it was because of the 390 injectors -- could you swap in the 450's and ecu without changing the cams? Would going to the M/T cams cause any noticeble negative effects in the low/mid rpm ranges anyway?

Actually, the easiest thing for me to do would be to bolt on a used 14b but I don't want to sacrifice the low and fast spool up of the 13g by going with the bigger turbo, manifold, and m/t cams. Plus, even with a small 16g I would only run 14 lbs max because I'm trying to run the car as a reliable performance vehicle which is sort of a contradiction and not an easy thing to achieve.

I was thinking about mating the '95 manifold to the 13g for its resitance to cracking -- was told by a few people that you can do this -- but even going bigger on that I'm concerned about the loss of backpressure and spool-up time. I put a 2-1/2" dp on with test pipe and I regret that I didn't go with a 2-3/8" dp instead because of the loss of too much backpressure.

I'm definately obsessing here -- maybe I need some prozac and a riced out honda with no engine mods!
"No Doctor, my DSM ISN'T talking to me again!"

 

[StyleElements]

Right now I'd rather use my 13g at 12-12.5 lbs for several reasons. With a 14b (or 16g) I would only be running 14lbs max BY CHOICE anyway and since that's only 1.5- 2lbs more I'd rather stick with the faster spool-up of the 13g

even tho it would be the same psi with a bigger turbo, a bigger turbo would push a greater volume of air

 

[91Bomb]

even tho it would be the same psi with a bigger turbo, a bigger turbo would push a greater volume of air

I have to disagree. The volume at the intake manifold would have to be the same. 14 lbs boost is the same whether it's from a 13g, 14b, or any turbo. There is a difference though in HP depending on what turbo is pushing the 14 lbs. The difference is that a 13g has to spin faster than a bigger turbo which means it is not as efficiently moving the air and heating it more as it does this to achieve the 14 lbs. So the 14b's charge would be cooler but the volume should be the same as the 13g's -- at least at 14lbs because the 13g isn't as efficient at that boost level. Correct me if I'm wrong about this.

You've got me thinking all the same -- I mentioned that I wouldn't want to trade my 13g for a 14b since all I woould be gaining is 1-2 lbs boost because I run 12-13 lbs on 13g and would run only 14lbs on 14b by choice. It WOULD BE like I was gaining more than 1-2 lbs though by the fact that the 14b @ 14lbs would be pushing cooler air into the engine than the 13g would at same boost.
Even though, I decided I'd get a pocketlogger so I can tune and squeeze out a safe boost level from my 13g, I'm guessing it'll be aronnd 12-13lbs and will soon find out.

 

[91Bomb]

get a data logger first if your that worried about it the 13b is a nice torqey little turbo but you want make any real power. re wire your fuel pump too. use the logger and and up the boost till you just start to get knock in a full run through 3rd meaning 1st no knock 2nd no knock 3rd maybe 1-8 counts on the data logger and that soloniod wont really protect you from sh*t forget that soloniod it would probly be such a resriction of you put the boost controller in wrong you could blow the turbo or maybe your engine! buy a pocketlogger first so you know what is happening first then start trying to sqeeze what you can out of it

Thanx -- the more I thought about it the more sense your reply made. Why should I be guessing when a datalogger will tell me everything I need to know.

 

[saw wave analog]

I have to disagree. The volume at the intake manifold would have to be the same. 14 lbs boost is the same whether it's from a 13g, 14b, or any turbo. There is a difference though in HP depending on what turbo is pushing the 14 lbs. The difference is that a 13g has to spin faster than a bigger turbo which means it is not as efficiently moving the air and heating it more as it does this to achieve the 14 lbs. So the 14b's charge would be cooler but the volume should be the same as the 13g's -- at least at 14lbs because the 13g isn't as efficient at that boost level. Correct me if I'm wrong about this.

this is complete garbage, you are wrong


cfm is what really matters, not psi. psi is a convienient way to measure what kind of air you are flowing because you know what the turbo is capable of. 14psi out of a 13b is most certainly not as much air as 14 psi out of a t76

 

[91Bomb]

this is complete garbage, you are wrong


cfm is what really matters, not psi. psi is a convienient way to measure what kind of air you are flowing because you know what the turbo is capable of. 14psi out of a 13b is most certainly not as much air as 14 psi out of a t76

Sorry dude -) but like I said, if you have a real boost gauge hooked up at the intake manifold and it reads 14 lbs than that is what you are boosting no matter what turbo is on the car. Of course the smaller turbo will be pushing hotter air than the 14b thus less power will come from it. The cfm measurements are telling you the flow capacity of each turbo: 13g = 360cfm; 14b = 405cfm; 'small' 16g = 505cfm etc. I still may be wrong though -- anyone else want to weigh in?

 

[saw wave analog]

you can have 2 cubic inches of air pressurized to 14 psi, or you can have 20 cubic inches of air pressurized at 14 psi. which one is more air? psi is an easy way to tune, because you know when your turbo goes out of its efficency range, and you know how many psi from whatever turbo you are tuning your motor can handle. yes a smaller turbo will generally be less efficient as far as heating up the air is concerned- a bigger turbo will allow higer psi while maintaining its efficiency.. but that is certainly not its only benefit, its also shoving a lot more of that pressurized air into the engine. compressed to the same psi, but a lot more of it.