Mahjik

iTrader: (1)

https://www.rx7club.com/showpost.php...68&postcount=7

jdhuegel1

I think this argument is endless now. There are tons of people that have done it and succeeded, and tons that have tried and failed. I remember back in 94-95 when guys were just putting a boost controller and a midpipe on otherwise bone stock FD's a beating the **** out of them. Most the time the damn PPF would be the first thing to break. My buddy got a repo'd one with like 13k miles on it, put an intake MBC and midpipe on it and drove down 270 every day looking for races. Went from Frederick to Ocean City I don't know HOW many times. Never broke. The thing was retarded fast. Stock sequential twins on like 15psi all damn day. This of course was way before we knew of, or gave a **** about recording data or making videos of it hoping to back up our claims 15 years later... Call BS if you want. Many of you don't like Peter Ferel either - but you should see the **** he put FD's through on the purple box and chipped ECU's; hell, even before that when there were no supporting programs.


Nowdays people wont even touch a FD without all kinds crap done. I don't know what has changed over the years though. The fact that people are modding cars that have sat in garages for the last 13-14 years and expecting them to stay together is something else though. They sure aren't like a 302.


What one guy has done, the next guy has failed at trying. It happens.

2007 ZX-10R

yeah, so why would you even CONSIDER risking a $5k motor build on a freakin $100 sensor?

pure insanity

skir2222

He stated it was back in 94 95, when I am sure not many performance parts were available. Trail and error, some get lucky some don't. Personally, I rather upgrade everything I can so I know it can be able to perform how I would like it to with out the worry or stress of it breaking.

fendamonky

iTrader: (6)

What if you're looking for an excuse to get a nice streetport?? =P


Seriously though. I was talking to one of the guys in England today and he said that the stock MAP sensor was good to 1.4bar.. That is well above 17psi, did the European/Japanese model 7's come with a different stock MAP sensor?

I ordered the 3 bar one from Rotary Performance anyway though (along with a couple other bits I wouldn't have been able to get from Banzai)... I've already dropped 8k on ensuring everything is done right, no point in skimping now (breaks out the credit card)

GoodfellaFD3S

iTrader: (213)

Same map sensor, i think the guy in England is just wrong

Even if you got the 3 bar from rx7.com, I'd recommend getting the jumper harness from Banzai. Crimp connectors suck, i had some issues with mine and ended up soldering them.

Also, if you're looking for a long healthy life for your motor and say there's no point in skimping, I'd recommend you pick up an Aquamist water injection kit

Silver7even

I wanted to note the this string is refering to absolute pressure, psia


Pressure is always measured relative to some reference. If the
reference is absolute vacuum, the pressure is absolute pressure, psia. If the
reference is local ambient pressure, the pressure is gauge pressure.

rollingsband1

i was thinking about getting a water methanol injection system anyways.. is that the same as the aquamist?

GoodfellaFD3S

iTrader: (213)

yup. http://www.aquamist.co.uk/

2007 ZX-10R

Rich has an aquamist on his Schwinn bike, too

Matt Hey

Chuck Westbrook used 4 different gauges and a Mini-VAC to measure the stock pressure sensor. He came up with a PIM of 4.907 V at 17.5 PSI. I also used a Mini-VAC and came to the same conclusion but only using 3 gauges. The sensor seems to be consistent even above 1 bar and that is what I run and I haven't popped a motor yet. I did rescale my P-Rows as P19 and P20 in a stock PowerFC are above what the stock pressure sensor can read so they are never used. 17 PSI should be a very rich P-ROW because it can not be determined if the boost is 17 PSI or 20 PSI and only the fuel from the 17 PSI P-Row will be used. I would not recommend boosting over 17 PSI with the stock pressure sensor and then only if the P-Rows are set up correctly and the error of the PFC boost reading is understood or corrected. However, Mahjik is absolutely correct! This is not our opinion but a fact for those who understand and have experience with the stock map sensor!

2007 ZX-10R

so, you tested one map sensor and now you can declare a "fact" for all the others? give me a break...you may have got lucky with one, or measured gauge pressure at a higher elevation, maxcooper got 16 from his https://www.rx7club.com/showpost.php...70&postcount=4 how far out on the ragged edge do you want to get? 17 psi is 1.17 bar, 16 is 1.1, we're talking about statistically insigificant differences from 1 bar, just so you can say you kept the stock sensor and saved $100

again, this entire debate is absurd, if you're running more than 1 bar gauge, you replace the sensor, unless you live in Montana or are just cheap and looking to cut corners

fendamonky

iTrader: (6)

A very good suggestion, and one that I have certainly considered. I'm trying to pull another deployment (Iraq this time) to finance a quality V-mount and AI.. My stint in Afghanistan over the summer paid for my upgrade to the world of BNR's (and all the other supporting mods that will allow me to run high psi on twins, or move to single w/ little more than the cost of the turbo) just in the nick of time come to find out my primary is going to ****, and will only boost to 7psi. Though I'm not running on a ported engine I'm still gunna see if I can't sequentially pull numbers (reliably) close to yours when you still had the BNR's. I'm hoping the fact that my compression on all faces ranges between 8.6 and 8.9 will help out there =P


As far as financing goes... I just had some ******* Air Force Major try to tell me that I am *not allowed* to volunteer to deploy to Iraq. I'm going to take the weekend to get my ducks in a row, get him to tell me, in writing, that I can't, than go have a chat with the IG... I guess he figures that because he's some O-4 (who's been passed up for promotion too many times) and I'm *just* an E-5 that it means I don't have any teeth. Shame...

Matt Hey

That would be 2, Mine and Chuck Westbrook's but who's counting?

maxcooper said ~16 psi and 17 psi is approximately 16 psi especially when using only 1 cheap boost gauge for testing or worse, the PFC boost data. Your point about the elevation is valid as the pressure sensor does read in absolute pressure and the boost is based on the current altitude. My elevation is about 1000 feet which is not extreme. There is plenty of room for elevation factors when well tested stock boost sensors read over 17.5 psi and we recommend not over 17 psi which means 16 psi max.

There is nothing cheap about it. Most RX-7 owners that boost 14-16 psi don't need to upgrade their pressure sensor. I bet more RX-7 owners boost this much with the stock sensor than with upgraded sensor. Some people lack the intelligence to be able to understand how to safely run the stock sensor but they are going to have trouble properly setting up a 3 bar map sensor too. Did you calibrate your 3 bar sensor or just use a PIM scale and offset you found somewhere? IMHO, between the PowerFC settings that need to be made and the wiring job to connect the new 3 bar sensor, it's riskier and less reliable for someone running low boost to move up to the 3 bar sensor.

rollingsband1

Ahh Military Woes! I served 4 years in the Army.. i dont miss it much, but i def dont regret my time served! had a blast! thought about joining the reserve now.. I have my degree now also so I can do OCS!! Yay!! Butter bar me up! :-)

2007 ZX-10R

yes

well, I disagree...Rich claims he popped an engine at 17 psi, I have too much $$$ in my engine build to unecessarily risk it with a cheap sensor, plus at some point I may want to go single

rollingsband1

Thats my whole point too.. if your going to be running 15psi or more you have some money under the hood anyways.. whats a 100 dollar part for extra comfort compared to the thousands you prob have under the hood anyways?


lol and i staretd this thread.. and now im involved lol! :-P

Mahjik

iTrader: (1)

Rich's note:


Having boost creep over what you are tuned for is no different regardless of the resolution you can get from the map sensor. You can pop a motor creeping to 14 PSI, which is WELL within the operating parameters of the stock map sensor, if you are running the stock ECU (or an ECU tuned for lower boost).

SPICcnmGT

+1 for the most truthful post in this whole thread.

I'm pretty sure Chuck has tested more than one.

And it's been proven time and time again that the PFC's boost reading is not what you want to go by as for as actually boost pressure.

2007 ZX-10R

huh?

SPICcnmGT

That means that you don't want to use the PFC's boost gauge/reading, to tune for an exact psi. Or in other words the PFC's boost reading isn't the actual boost you are running.

ex. 1.15kg/cm2 on the PFC comes out to 16.353psi, but when actually tested 1.15 on the PFC comes out to 17.5psi by multiple gauges.

2007 ZX-10R

as far as I know my PFC gets boost readings directly from the 3 bar GM sensor, not from any "boost gauge", and I thought all of them were set up like this

gauges aren't necessarily all that accurate, depending on what you're using...I would tend to trust the electronics (I don't even watch my boost gauge anymore because I know it's off)

Matt Hey

Just for reference, Here's an old thread where I posted the results from using the Mity-vac. Max pressure reading was between 17.5 and 18 psi using VDO, Autometer and Mity-vac gauges as reference. See posts #11 and #12...

https://www.rx7club.com/power-fc-forum-47/barometric-stock-2-bar-sensor-does-work-466783/

I told how to make the PFC boost reading accurate but I never heard from anyone else that tried it. The PFC boost reading is based on the PIM scale and offset values.

2007 ZX-10R

nice essays on the linked thread, not sure who's going to actually read it, though

what we really need is a direct comparison between the stock sensor and the GM 3 bar from 1 bar and up....even though I think this whole thing is silly because it's a $75 sensor so just use the right part for the job above 1 bar gauge

SPICcnmGT

Correct, which means if it is reading 15psi that is not the actual "TRUE" pressure you are running.

No their not, but from all test I have seen the mechanical boost gauges read almost identical. So either all the gauges that were used to test the stock MAP sensors were all off by a few psi, or the MAP sensor just reads low, what would you believe??





Maybe if you would research this stuff instead of posting in this thread you might learn something instead of stating, that only running a 3 bar map sensor is going to keep your engine from blowing your engine.