Spec R

i keep reading about how its not about how much boost you run but how much hp you make kills stock pistons/rings/sleeves.

how valid is this?

I recently had my car tuned at 6.5-7psi and i want to turn it up a little, maybe to 9-10 max. my main concern is NOT running lean since i'm at a safe 12.5 afr on 440cc injectors. see sig for power. my compression reads about 185psi across the board, but i do have a 1qt/1000 mile oil consumption problem (likely a valve seal or oil control ring) and a higher than normal leakdown on cylinder 2 (18%, where the others have 7-8%), but my dyno numbers dont show any power loss with my current setup. in fact, my dyno numbers are higher than what similar setups to mine have run.

Stock LS B18B with 126k miles on it. i've read many stock internal LS guys here on HT boosting like 12psi no problems putting out mid 250s, but i dont know the details of their setups.

any help is appreciated thanks in advance.

elpiar

it's valid cause the effective hp you're making is proportional to the amount of fuel you put in, which (considering constant AFR) means proportional to the amount of air you put in.

Yes, boost means pushing more air molecules in, but apparently the small turbo high psi will limit the amount of effecting boost inside cylinder.

In short, yes, horsepower blow engines, not boost. In stock GSR I know 280-300whp is marginal. I don't know about LS

ProjectDarkBlack

there is no "limit", and you can tune cars different ways to make power safely, i.e. tuning for low peak cylinder pressures. You shouldn't worry too much you can replace that short block for $200-300. I have read and been comfortable with 300whp being the reasonable reliable "limit". Some people go far beyond that and do great, a lot has to do with your tuner. If this car is your daily I would suggest buying a beater. Not only is it important to have something stock and reliable, it will help during the install, and working out the kinks. Don't expect everything to go together perfectly the first time because 9 times out of 10 **** doesn't turn out right.

as far as blowing motors goes, horsepower increases usually increases cylinder pressures, and cyclinder pressures kill motors.

HiProfile

My brother's teg is currently @7psi or so, 310's w/fmu - 96 gsr. Makes ~265whp @7psi and the last owner saw 303whp @10psi. From what I know, the DRAG kit has been on for 2+ years w/54trim t3/to4, no issues.

I'd say 300whp tops for a relaible DD b18b1. I'd also suggest it always has a wideband in it, and gets retuned immediately if needed.

Spec R

The turbo setup is already in the car, you can see the numbers i put out in my sig. i'm very grateful that i do have a daily driver (a 95 240sx SE), but i dont see any reasons (other than theft) not to drive the teg daily either.

i guess i need to emphasize that my concerns lie in the gray areas of the health of my engine (symptoms that would indicate more than normal wear - burning oil - been doing it since i got the car 100k miles ago / leakdown on cyl 2), despite my "healthy" dyno numbers.

its more like i should ask "have any of you blown motors with sufficient fuel and safe ignition?" mind you, my vacuum numbers and oil pressure are excellent too (21-22 inches at idle and 20psi idle 80psi above 3k).

i did the math....14.7 psi atmospheric pressure + 7 psi boost = 21.7psi

now 188whp divided by 21.7psi = 8.66whp per psi

7 psi boost * 8.66whp = 60.64 peak whp i gained from boosting at 7psi.

now, if i boost an additional 3 psi, that should be 25.98whp extra if nothing else changes.

does that sound about right? i'm still running the stock MAP sensor, so i dont plan on going beyond 10 psi.

i dont want my engine to let go, but i'm somewhat prepared (its not like i have a "blown motor savings account" though) if it does. it would just be an unnecessary pain in the ***.

R@mon

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Spec R &raquo;</TD></TR><TR><TD CLASS="quote">i keep reading about how its not about how much boost you run but how much hp you make kills stock pistons/rings/sleeves.

how valid is this?

I recently had my car tuned at 6.5-7psi and i want to turn it up a little, maybe to 9-10 max. my main concern is NOT running lean since i'm at a safe 12.5 afr on 440cc injectors. see sig for power. my compression reads about 185psi across the board, but i do have a 1qt/1000 mile oil consumption problem (likely a valve seal or oil control ring) and a higher than normal leakdown on cylinder 2 (18%, where the others have 7-8%), but my dyno numbers dont show any power loss with my current setup. in fact, my dyno numbers are higher than what similar setups to mine have run.

Stock LS B18B with 126k miles on it. i've read many stock internal LS guys here on HT boosting like 12psi no problems putting out mid 250s, but i dont know the details of their setups.

any help is appreciated thanks in advance.</TD></TR></TABLE>

just two things I noticed. 12.5 afr isnt exactly as safe as it should be, realistically it would be safer at or around 11.8 afr. also, any oil consumption, unless its leaking past a seal and dripping on the ground, is being burned by the motor, if one or more cylinders are burning oil, oil reduces the octane of gas and will cuase pinging or detonation. so be careful, even though the motor made good power just make sure you keep the oil consumption under control. just me .02.

Ramon

tthame1

I'd say that it is fairly valid. My stock b16 ran just fine and lasted about 1.5 years boosted making 280 whp (7-8 psi). As soon as I turned it up to 10 psi it destroyed the ringlands on all four pistons. This is with an 11.8 afr.

NoobieREDLS

could the pcv valve be the reason your burning oil????

Spec R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NoobieREDLS &raquo;</TD></TR><TR><TD CLASS="quote">could the pcv valve be the reason your burning oil????</TD></TR></TABLE>

no, i've changed it twice before going turbo. i have a brass one now that rattles pretty loud.

Spec R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by R@mon &raquo;</TD></TR><TR><TD CLASS="quote">

just two things I noticed. 12.5 afr isnt exactly as safe as it should be, realistically it would be safer at or around 11.8 afr. also, any oil consumption, unless its leaking past a seal and dripping on the ground, is being burned by the motor, if one or more cylinders are burning oil, oil reduces the octane of gas and will cuase pinging or detonation. so be careful, even though the motor made good power just make sure you keep the oil consumption under control. just me .02.

Ramon</TD></TR></TABLE>

here's the graph, its in the general area of 12.5 afr.


i have a keen ear for pinging and detonation, and i havent heard anything. come to think of it, since i've gone turbo, i actually think my consumption went down...i did get a new oil pan gasket, and there was a good amount of residue on the pan. so maybe i was losing oil there, while the car was moving. i havent really kept track of the miles so far though.

adseguy

Your calculations are about right. Most LS's make around 8-10PSI per/lb and GSR's (or higher compression motors) make a little more then that.

IMHO, sounds like your motor isn't the healthiest, but I see no problem in running the 10PSI of boost you want to. Remember adding more HP doesn't stress the engine more. HP accounts for only 20% of engine damage...the real stress comes in high revs and cold starts that's where a lot of "damage" occurs. the 300whp limit is obviously just thrown around and I am very willing ot bet most can do 350 even 400whp on an LS DD, <U>BUT</U> if even one cycle of detonation occurs that motor is most likely toast.

Boost again means nothing unless you really get high up (25+). I run 18-19PSi on a stock LS making over 328whp now and this IS my DD no problems. I also have it very well tuned with safe AFR's. your 12.5 is actually OK, BUT if you go ANY higher then you may run the risk of detonating. The reason for running such a low AFR is because if the fuel pump decides to loose A LITTLE fuel pressure or the FPR decides to not push out as much fuel pressure or an injector decides to become a LITTL ebit clogged....you get my point.....the fueling needs will still be at a safe/ideal range for combustion, but no longer safe for reliabilty. Think of it as a safety margin.

I would just tune to the map sensor (10 PSI) and you should be fine. This assuming the most important part, timing, is tuned well . GL

raene

Look up det cans, and you'll get a better handle on detonation.

IMO that AFR is fine but a bit risky, I like to see it richer. It's not optimal for power but it helps a bit with longevity.

Spec R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">Your calculations are about right. Most LS's make around 8-10PSI per/lb and GSR's (or higher compression motors) make a little more then that.

IMHO, sounds like your motor isn't the healthiest, but I see no problem in running the 10PSI of boost you want to. Remember adding more HP doesn't stress the engine more. HP accounts for only 20% of engine damage...the real stress comes in high revs and cold starts that's where a lot of "damage" occurs. the 300whp limit is obviously just thrown around and I am very willing ot bet most can do 350 even 400whp on an LS DD, <U>BUT</U> if even one cycle of detonation occurs that motor is most likely toast.

Boost again means nothing unless you really get high up (25+). I run 18-19PSi on a stock LS making over 328whp now and this IS my DD no problems. I also have it very well tuned with safe AFR's. your 12.5 is actually OK, BUT if you go ANY higher then you may run the risk of detonating. The reason for running such a low AFR is because if the fuel pump decides to loose A LITTLE fuel pressure or the FPR decides to not push out as much fuel pressure or an injector decides to become a LITTL ebit clogged....you get my point.....the fueling needs will still be at a safe/ideal range for combustion, but no longer safe for reliabilty. Think of it as a safety margin.

I would just tune to the map sensor (10 PSI) and you should be fine. This assuming the most important part, timing, is tuned well . GL</TD></TR></TABLE>

well a while back i got my car baselined NA on a different dyno, because i was upset about the oil consumption and other issues, and i put out like 96whp and 76 ft lbs. so when i went to get my my car tuned after the turbo install, and saw the new numbers i was immediately happy knowing that the prior dyno didnt mean anything (bad dyno - i recently found out the dyno was defective). so i know it wasnt as sickly as 96 whp sounds. if i do the math my engine should put out 128 whp if it was NA. not bad for a stock LS. its not a freak motor by all means, but not a dud other, which is what i was really happy about.

I see what you're saying with the fuel, it makes a lot of sense. i may change a few things here and there and get it re-tuned.

my ignition timing is set at 16 degrees base, with about 1 degree retard per pound of booost.

any other advice to point me in the reliability/safety direction? i have a lot of "NA is best" die-hard acquaintances that would love to see my engine let go. but then again a lot of those guys have never driven or been in a well tuned turbo honda (go figure). i want to prove to them (and myself too) that i can have reliability as good as NA.

thanks for the help everyone. sincerely, honda-tech usually doesnt net me good info like this.

oh yeah, is vacuum a good indicator of the health of my rings (outside of a compression test of course)? i'm always referencing it at stop lights and such after boosting to see if anything went awry.

99lspwr

Well, I can tell you im not quite at the 300 mark, but probably close to it with my stock ls/ 60trim..... And I have b.s. engine management as well....Based on my weight/trap speeds I would say Im at the 280 whp mark or so...

Spec R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99lspwr &raquo;</TD></TR><TR><TD CLASS="quote">Well, I can tell you im not quite at the 300 mark, but probably close to it with my stock ls/ 60trim..... And I have b.s. engine management as well....Based on my weight/trap speeds I would say Im at the 280 whp mark or so...</TD></TR></TABLE>

how much psi?

mike93boost

richen that up. 12.5:1 is not safe.

99lspwr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Spec R &raquo;</TD></TR><TR><TD CLASS="quote">

how much psi?</TD></TR></TABLE>

13-14...

Spec R

Edit : contacted my tuner, he said that 12.5 on the graph equals 12.1 in the engine or so because of the catalytic converter and the tailpipe sniffer factor.


Modified by Spec R at 10:48 AM 4/10/2006

spoon95eg

Finally u went to dyno already numbers r kinda low though turn the boost up to 10-12psi so ull see 200 up whp/wtq

Btw next time don't go to hook-ups cuz they suck at tuning cars since ur in LA

Do it dyno is at long beach bad *** tuner his name is bubba tell him I recomended u to him call him up 562 4246162 ask for angel or him good luck

Spec R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spoon95eg &raquo;</TD></TR><TR><TD CLASS="quote">Finally u went to dyno already numbers r kinda low though turn the boost up to 10-12psi so ull see 200 up whp/wtq

Btw next time don't go to hook-ups cuz they suck at tuning cars since ur in LA

Do it dyno is at long beach bad *** tuner his name is bubba tell him I recomended u to him call him up 562 4246162 ask for angel or him good luck

</TD></TR></TABLE>

what do u mean finally i got my car tuned? i got it tuned soon after i went turbo. i dont see why they sucked at tuning my car, he did exactly what i wanted him to do. if i had my own dyno and off-car air fuel meter, and all the tuning tools i would have done it exactly the same as him. i know my numbers are lower compared to other boosted LS's, but those cars do NOT have the SAME setup as i do. I was aiming for torque and midrange power anyway, not peak. read my posts above to see the math.

i know about bubba and his tuning, as well as everyone else in southern california. i was in contact with everyone before making my decision to go to hook-ups and he was the only one who didnt talk to me like i was a dumb kid off the street who doesnt know anything about tuning or cars in general.

Besides, every tuner has had his good and bad days. i've read many of the horror stories about Bubba, S. Church, R&D, and Hook-ups.

thanks for the help though! i found the extra couplers that i lost the other day too...

Rico

I've read a little of this thread at some point stock motors are going to pop. Back in the day people thought DIREP972 was crazy for running 1 bar on a bone stock LS. When I told him that I was running 26 PSI on a bone stock LS he thought I was crazy, so stock blocks can make some power..

spoon95eg

sorry I just hate them @ hook ups they dyno my n/a motor right!! its bugging and it run rich and when his dynoing it he didn't even move the cam-gears the timing fuel decrease/increase and he can't fix the problem and he told me to buy the stock fpr for 40 bucks so the bugging will go away and didn't do **** he told me to buy the fpg to see where's the fuel pressure is didn't **** and they like in a hurry cuz it was like 5:45 pm fucked everything so don't trust them and their rip off I paid 100 bucks for stupid tune


Modified by spoon95eg at 9:30 PM 4/10/2006

Westrock2000

I saw someone compare it to a GSR. You have to remember that 300HP in an LS is going to be more load than 300HP in a GSR. Thats because LS's fall on their face at about 5400 RPM, so your peak TQ will be rather low. That means that you are going to need like 280-290 TQ to get 300HP out of an LS, where as a GSR can hold the torque out to 7000-7500 RPM, so it may only need 200-240 ft-lbs of torque. Torque is the actual amount of "force" your engine is making, horsepower is just how long its doing it.

Tony the Tiger

The 300HP limit is a good number to start with. Just remember that the more power you make, the less margin of error you get. A better accuracy would be to look at the torque numbers too. So look at your situation and see if you can risk pushing more power with obviously less reliability if you plan to run more boost (ie: beater to drive around, blown-engine fund like you've mentioned).

It's quite funny how everyone would tell you that you can easily push over 300WHP and have it last, but I can guarantee you that the same engine and same good tuner running at a lower 260 WHP is going to be more reliable, offer more margin of safety and last longer. You can't deny that.

If you are a confident and experienced tuner and have taken care off all the supporting upgrades (fuel system, ignition, etc...) you can break that limit and be just as reliable as the next guy who is not as well tuned and well setup.

This HP limit would also depend what type of gas you get at your local pump. Obviously the same 300HP is much more safe for a guy who runs 93 oct than the other guy who runs 91 **** water.

sleepingEg8

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ProjectDarkBlack &raquo;</TD></TR><TR><TD CLASS="quote">as far as blowing motors goes, horsepower increases usually increases cylinder pressures, and cyclinder pressures kill motors.</TD></TR></TABLE>

but cylinder pressure increases, ARE the horsepower increases.. you gotta do it!!!