My boost gauge is reading 9 psi until i get close to the VTEC point where it hits 7psi then after the VTEC 6psi; I am using the stock JRSC pulley and have not changed any pulley sizes on my car yet I am getting 9psi consistently; Has anyone else had the same results??
--I LOVE the boost but I am really worried that my stock internals might give out at some point from running 9psi without any type of intercooling. Does anyone know if I am okay or should I be worrying, my car is a daily driver and I need it to be dependable. Any help??
a lot of people are seeing this. i think the consensus is that if the engine doesn't breathe very well down low, you'll see a higher boost reading in the manifold. that doesn't mean the engine is actually experiencing 9psi, it means air is backed up in the manifold. the blower is pushing the same relative amount of air at 6000 as it as 4000, the engine is just restricting it. i don't know if the restriction is exhaust, cat, header, or head. since it goes away after vtec, i'd guess something with the head and the low cam.
anyone have a better theory? the above sounds a little dicey to me.
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Originally posted by zarmchicoca My boost gauge is reading 9 psi until i get close to the VTEC point where it hits 7psi then after the VTEC 6psi; I am using the stock JRSC pulley and have not changed any pulley sizes on my car yet I am getting 9psi consistently; Has anyone else had the same results??
--I LOVE the boost but I am really worried that my stock internals might give out at some point from running 9psi without any type of intercooling. Does anyone know if I am okay or should I be worrying, my car is a daily driver and I need it to be dependable. Any help??
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Is there any way to manually control the vacuum bypass that jackson uses to prevent this from happening? e.g. eliminate boost when not in VTEC. It sure sounds like something is up with the breathing, has anyone called Jackson Racing to see what their take on it is? if the manifold is at 9psi then I'd say that the engine is seeing 9psi at least briefly as well.
Given that there is probably some blow through in VTEC (although I'm talking out of my ass until I look at the profiles for the stock cams better) that might account for the boost going down, too.
there's a device called the ebl which limits boost on a jrsc, i don't recall exactly what method the creator (zip on hostboard fi teg forum) uses. check it out over there, i don't think it's been tried on a prelude yet.
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Originally posted by xtal Is there any way to manually control the vacuum bypass that jackson uses to prevent this from happening? e.g. eliminate boost when not in VTEC. It sure sounds like something is up with the breathing, has anyone called Jackson Racing to see what their take on it is? if the manifold is at 9psi then I'd say that the engine is seeing 9psi at least briefly as well.
Given that there is probably some blow through in VTEC (although I'm talking out of my ass until I look at the profiles for the stock cams better) that might account for the boost going down, too.
I'd like to hear what JR has to say.
Steve
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Do you think getting a Thermal R&D exhaust would benefit my system then? Perhaps then it would free up my flow and give me a true 7 or 6 psi of boost?
--What I'm wondering though is if I am gettting 9 psi at the manifold, will it be detrimental or dangerous to my stock block? Does anyone know this?
I think it doesn't matter. I have all the free flowing cr*p and my gauge still reads 9psi. I am about to take off my cat as soon as I get a test pipe and it will probably still read the same.
I just talked to JRSC today and the tech guy, some guy named Keith, told me that I needed to take it back to my shop and see if my gauge and all vacuum lines were hooked up properly and to have the shop check my boost pressure with their gauge.
--I told him it might be a restriction in my exahaust and he said that sounded very doubtful because they test the kit often on bone stock preludes and they still read 7 & 5 psi so he doubted it was that.
--He said that if it was reading 9 psi and the gauge was correct that my engine would very likely be seeing 9 psi of boost ( which is exactly what I don't want to hear bacause I cant have my engine blow up anytime soon.
Chomorro, I was wondering how long youre gauge has been reading 9 psi of boost? Have you had it dynoed or tested on a shops boost gauge, I'm curious to know....are you worried about your internals.
--Any advice anybody?
Well i have been boosting 9 PSI for about 3 1/2 months now. When i first installed the kit in my car i was hitting 6-7 psi of boost. Then i tightend up my SC belt because i was hitting 4- 6 PSI of boost. After i tightend up my SC belt my boost went back up to 6-7 PSI. When i took my car to the dyno. Shawn who was tunning my car wanted to tighted up my Serpentine(SP) belt, because i wasnt getting the HP i was suppose too. Once he tighted up Serpentine belt, i went from 205.2 HP & 184.8 TQ to 222.5 HP & 189.9 TQ Since my Dyno tunning i have been Hitting 9 PSI of boost in all gears. I hit a little less boost in 1st gear when i do a hard launch. The boost level creeps down a bit, prolly because of the belt slipping a bit.
Well if my car is making a TRUE 9 PSI of boost, i have not seen any problems what so ever ! and i can still go to 2- 3 clicks past min. on the BTC without detonation remeber i been hitting 9 PSI of boost for about 3 1/2 Months now with no problems .. Car runs like a champ !
Here is link to my Dyno picture once i tightend up my belt.
Thats what I thought was my problem, my belt was much tighter than everyone elses. Did you here any signs of belt slippage before they were tightened????
My belts were a little too tight. When I went down a steep hill at 50mph at the bottom I would be at 35mph. I loostened them a little and I still hit 9psi of boost. I over tightened them when I did a vavle adjustment.
Originally posted by chomorro Thats what I thought was my problem, my belt was much tighter than everyone elses. Did you here any signs of belt slippage before they were tightened????
My belts were a little too tight. When I went down a steep hill at 50mph at the bottom I would be at 35mph. I loostened them a little and I still hit 9psi of boost. I over tightened them when I did a vavle adjustment.
Actually, I didnt hear the belt slipping at all. I just noticed my car was acting a bit sluggish and my boost levels where down. So i tighted up the SC belt and VOLA ! I felt the power increase.. Much better
You know, I'm beginning to think it's my belt that's slipping again.
And I think it's the longer Alt-A/C belt, too, because I've screwed with the tension on the shorter one for some time now (not to mention replacing it with a Gatorback belt).
It sucks not to have full boost in the first three gears. Boost gauge shows a noticeable 'stepping down' around 5-6K RPM. Really annoying. Spraying belt dressing helps a little, but only temporarily.
However, in 4th gear, I've noticed that at WOT in higher RPM (which I rarely do), I see the boost gauge register a solid 9psi!!!. No stepping down. A lot of power.
Looks like I'll take another stab at that serpentine belt.
So the consensus that I'm getting hereis that it probably has something to do with the tension of my belts, and probably my serpentine belt?? Yet JR told me that the kit was not capable of 9 psi without a different pulley and so that somethin was wrong.
-Does everyone agree that itis probably not related to restricted exhaust or clogged catflow?
--also, has anyone actually hitting 9 psi on their gauges had it confirmed on their tunin shops boost reader that they are hitting a true 9 psi? I'm still a little weary of boosting 9 psi especially since I'm in cali and we get no better than 91 octane gs
I get my testpipe in a few days and I will let you guys know if the boost drops. Alright someone else found the power of the liftime warrantied gator back belt.
Iranman do you like that crazy whistle it emits at part throttle?
i dunno guys, this theory is kind of shady - what you're basically saying is that the kit develops 9psi but because of belt slippage most people get less than that.
i don't agree that it's not related to restriction. the blower moves a certain amount of air per revolution, the number of revolutions is fixed to a proportion of the number of engine revolutions. the displacement of the engine is constant, as is the engine speed in 1st, 2nd, 3rd, 4th, or 5th gear. if you hooked the same blower up to a b16 turning at the same speed it would develop ±37.5% more boost. similarly, if you clogged up the intake valves, the engine would move less air and the boost would appear higher on the manifold side. this is why you see less boost after vtec; the displacement is the same, the relationship of engine speed to blower speed is the same, but the engine is breathing more freely, moving more air relative to it's speed and displacement so the fixed air output per rpm of the blower is proportionally less.
to take the extreme, consider what would happen if you simply disconnected the blower from the intake manifold and ran a seperate pipe into the atmosphere. how much boost would a pressure gauge in that pipe read as you cranked the blower? none. give the pipe a restriction at the end, and you will start seeing positive pressure. close it off completely and you'll see a hell of lot.
this is why the guys at "9psi" aren't making 50% more power than the guys at "6psi." the 50% more pressure is due to 33% less air being moved. AFAIK, it HAS to be, since all M62 blowers move the same amount of air per RPM.
am i missing something here?
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Originally posted by zarmchicoca So the consensus that I'm getting hereis that it probably has something to do with the tension of my belts, and probably my serpentine belt?? Yet JR told me that the kit was not capable of 9 psi without a different pulley and so that somethin was wrong.
-Does everyone agree that itis probably not related to restricted exhaust or clogged catflow?
--also, has anyone actually hitting 9 psi on their gauges had it confirmed on their tunin shops boost reader that they are hitting a true 9 psi? I'm still a little weary of boosting 9 psi especially since I'm in cali and we get no better than 91 octane gs
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Schwett: Good analysis! However, what I wonder is if the restriction is causing the engine internals to get the 9psi stress (which I would imagine). Has anyone had their setup checked with a 2-bar sensor voltage reading, or some other shop guage that's calibrated?
Sounds like something is going on here, even if it's only miscalibrated guages.
i think it would depend where the restriction is. consider a restriction in the intake manifold; the manifold on the blower side of the restriction would see 9psi, but nothing on the other side would b/c the quantity of air moved through the restriction is still only 6psi worth at the full displacement of the chambers on the other side. sort of like a river with a neck - the water moves fast before the neck, but slows down again afterwards. fluids are different in some respects due to their incompressibility, but i think the analogy is similar.
we do the same thing in mechanical system design all the time; areas where noise is less of a concern than size see a significantly higher static pressure and velocity, then the ducting increases later to decrease noise and vibration but move the same amount of air.
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Originally posted by xtal Schwett: Good analysis! However, what I wonder is if the restriction is causing the engine internals to get the 9psi stress (which I would imagine). Has anyone had their setup checked with a 2-bar sensor voltage reading, or some other shop guage that's calibrated?
Sounds like something is going on here, even if it's only miscalibrated guages.
Steve
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Originally posted by schwett i dunno guys, this theory is kind of shady - what you're basically saying is that the kit develops 9psi but because of belt slippage most people get less than that
Well im saying im getting 9 psi of boost because of Tighting my serpentine belt and SC Belt. When my serpentine belt & SC belt was loose i was only making 5-7 psi of boost, but when it was tightend my boost level did go up and i made a great deal more HP. That was my second run on the dyno and we didnt do anything to adjust my fuel, only the serpentine belt and SC belt.
But you do make a very good point Schwett.
Im just saying my boost levles are the results of tighting my belts since i saw in change in boost levels when they got tighted up.
Were not saying that we are hitting 9psi of boost power. Just that we got full potential by tightening up the belts. Whether our gauges are incorrect or whether our tapped hoses are in the wrong place, that is still to be determined. I know I am not hitting 9psi of boost but my gauge reads full power with tight belts. I used to read 6-7 psi just like you but I found a leak in my connection to the gauge and repairing didn't change the power, just the reading.
You guys could always go to the eaton website and read the maps of the M62 blower. If you can determine the airflow at whatever rpm, you could get a pretty good estimate of the power you could ultimately make with good tuning. There are a few general formulae for cfm/hp, but knowing the blower's capabilities, temps airflow could help making more power...
Although I am no engineer I tend to agree with Schwett about the restriction and it effect on boost levels, and although my gauge reads 9 psi before VTEC i am fairly sure i am not getting a full "real" 9 pounds of boost.
--Talking to Keith it really sounds like the reading is wrong at some point, probably produced by a hose that is hooked up wrong or a false boost reading. I am still running the stock
JRSC Fuel pressure perameters for the normal 7-5 psi and have had no severe detonation (though my BTC is stilll set in the middle) or any indiccation on my air/fuel meter of a lean condition. Keith said that (and I confirmed this by asking questions from a couple shops in the sac area) that if I was getting a true 9 pounds I would have severe detonation because of the fact that the fuel settings had not been adjusted for the extra pounds of boost.
I am going to take my car to the shop this monday and have them check all connections and test their boost readings on their shop boost meter and then (hopefully) I should have some answers for what might be going on. If anyone gets any more info or a test confirmation of "true/false" readings of 9 psi on the shop gauge, please post this.
--One more Question; if I am getting 9 psi bacuse of a restiction, isnt this still entering my combustion chamber with 9 pounds of boost and wouldnt this present more strain on the internals regardless of how much extra HP was or wasnt realized from the extra boost??? Thanks for the info; sorry if its a stupid question but try answerin anyways
"One more Question; if I am getting 9 psi bacuse of a restiction, isnt this still entering my combustion chamber with 9 pounds of boost and wouldnt this present more strain on the internals regardless of how much extra HP was or wasnt realized from the extra boost??? Thanks for the info; sorry if its a stupid question but try answerin anyways"
I think schwett did a good job on this one.. they let us electricals off without the brutalities of fluid dynamics. What's happening is that because there is a constriction, the gas (air) is forced to compress to fit through the smaller area. However, because (presumably) the intake manifold or combustion chamber expands down the line, the pressure reduces.
Think of the shape you'd get when you tape two 2L pop bottles together. If you happened to put your meter where the necks meet, you'll get a higher reading.
I just went to my tuning shop today and I'm pretty worried/pissed. The shop's boost gauge also read me as producing 9 psi/ 7 psi on their gauge. He talked to the tech guy at Jackson while he tried to find the problem; then eventually told me I was going to have to leave the car with him over night and reset the computer and see the car when it was completely cold and try (with JR's help) to see what the problem was. I have a strong feeling that he stil might not find the true cause for this happening since neither he nor Keith at JR really seemed to know what was going on. At this point I am fairly certain that it is something related to Schwett's earlier thread on this post; I believe taht there is some sort of resriction maybe at an intake valve or the head. What really is bothering me is whether or not this 9 ps(which I am almost positive is not a true 9 pounds of usable boost) will be seen by my internals; if so, my engine might not stand up very long.
--If it is a restiction; does anyone on here know how I might be able to get a restriction like that cleared up without removing the head? Anyway of cleaning the intake valve in a truly effective way? Any way of clearing that restriction?? Please let me know any info anybody has, Thanks
What is wrong with making 9psi? Are you all worried about blowing your motors? After the first few sprints to redline, if there were any problems, you'd know.
I don't understand, are you guys getting upset about getting 9psi off of a stock JRSC? The amount of boost doesn't destroy engines, its detonation, improper tuning and the actual hp made (compressing the internals and the sudden change in direction). There are a hundred other little things, but if you're not making outrageously high hp #s on the stock block, there isn't any reason to be upset about making 9psi. Anything more than the JRSC claims is a godsend. People usually have to buy stuff to get any type of upgrade from JR.
As for the issue if 9psi is actually 9psi...???? Could it be anything else? If you really must know, there are very accurate gauges out there. I don't see why you'd need one when the most important issue should be detonation and fueling. Yes detonation is amplified with boost, but that is what your little retarder thing is for, right?
I guess I am just bored, bring on the flame thrower.....
I, too, don't understand what all the fuss is about.
Like schwett said Eaton blowers move the same amount of air per revolution. Assuming you're using the same sized pulley (3.4") as the rest of us, you shouldn't be worried about deviations in boost readings. Remember that whatever 'boost' is registered by your gauge is simply the built-up pressure that is stuck in the manifold (the other fraction of air is inside the combustion chamber).
This is why you can't compare boost levels between a turbocharger and a supercharger. A turbo will generally flow more CFM at higher levels of pressure. You can make a supercharger create more boost just by plugging up the exhaust. So what? As long as your belts aren't slipping you should be a happy camper.
Why don't you take the car to a dyno (preferably one w/ a wideband o2 sensor) to see your power levels?
Since my Dyno tunning i have been Hitting 9 PSI of boost 
in all gears. I hit a little less boost in 1st gear when i do a hard launch. The boost level creeps down a bit, prolly because of the belt slipping a bit.
