RonKMiller

I don't know **** about RX7's - really.

There are SO many guys on this forum that eat, live and breathe this car and have invested untold sums of money and time on this vehicle. THEY know RX7's. I could name a hundred at least. (and, umm, Max Cooper would be right at the top of MY list.....)

I just hope to dole out a few of life's lessons on cars and mechanical things, period. I hate seeing guys waste their hard earned money on stuff they can easily fix by themselves. That's what being an old fart is all about. I've been very fortunate to have some great toys to play with during my life. Some fly, some float, and some ****. (fill in the blanks...) My advice:
LEASE 'EM!

Many thanks for the compliments, but I spend most of my time on important **** - like younger women, older whiskey and mo money.

Stevey629

alright well heres the deal, I have already changed my plugs, wires, oil filter, oil, and fuel filter. The vacuum lines have been replaced with silicon ones, and an aluminum AST was installed. I had this done no more than 200 mi. ago, so the stuff is practically new. I have done all the preventative maintenance I can think of for the time being.

Why the hard starts then? Oh, and another thing, is that my add coolant buzzer comes one sometimes at ACC, after I shut the car off, and click over to it. I can't figure that problem out, and have had my mech check it out three times already, along with mazda. Sorry for the ramblin', but I have on other way to get this crap off my mind. I worry about the car so much, I can't even have fun driving it yet.

adam c

iTrader: (2)

So you were running:
1.Catback
2.Intake mod
3.Downpipe
4.Efini y-pipe
I count 4 upgrades on the stock ecu. If you were only running 10psi with no boost controller, I would say that your car isn't running as strong as it should.

My car was boosting to 12.5 with an M2 ecu and a downpipe. When I added the Y-pipe and the airbox mod, it went up to 15.5. Time for a boost controller!

If you think that opening up the stock air box won't increase your boost, you are mistaken

kento1

Remember that I was using the stock ECU. Perhaps RonkMiller or Mahjik or another highly experienced member will correct me, but my understanding is that the stock ECU does what it can to limit boost to 10 psi. If your engine is flowing more air than what the wastegate can handle (like the transition), then you'll exceed 10 psi, and even a boost controller will do you no good-- the reason many port their wastegates. But I still had/have the stock cat, which does impede flow, even with the intake mods I've done. So the stock ECU could keep boost from exceeding 10 psi, even with those mods.

If you had an M2 ECU before doing any other mods, then your stock psi limit was disabled, so your results would be different. I was just wondering if those were actual results you documented, or your estimation.

adam c

iTrader: (2)

The numbers I posted for my car are actual results. The other numbers are potential outcomes for upgrades. I currently have a manual boost & prespool controller. When I referred to boost controller, I was speaking of controlling boost at all levels, including transition.

I do not agree that the stock ecu will keep the boost level at 10. If it did, no one would preach the "3 mod rule".

What's the scoop on your radiator/intercooler fit?

Kento

Adam,

Sorry, I guess my explanation wasn't good enough. You're a bit mistaken on what I was explaining, and asking. I was asking whether you were estimating the boost increase with the RB airbox mod and K&N, or whether you had actually measured that with a stock ECU with no other mods. I don't disagree that opening up the airbox will increase boost, but I was wondering if the RB airbox mod would increase boost that much.

I believe it was Max Cooper who did some wideband experiments with a stock ECU and various mods to dispel the "three mod" myth. Granted, every car is different, but my car fell right in line with his findings. I think the 3 mod rule was made because people were installing a midpipe w/DP & CB, and that opens up flow a hell of a lot. I was still in the safe zone with the stock ECU and all those mods, because I had to stock cat (which impedes flow quite a bit); I drove the car for nearly 6 months with that setup. I've driven another car with a bunch of mods w/stock ECU (and the stock cat), and it was the same; 10 psi max. If a motor exceeds 10 psi with the stock ECU, I'd say it's because the modifications are allowing it to flow more air than the stock wastegate can handle-- which is what I was referring to with regards to a boost controller doing you no good in that case. Or, in the case of the transition, where the boost spikes quicker than the stock ECU has time to react.

I need to find out whether the Fluidyne radiator sits higher than the stock rad when mounted, because the SMIC sits atop the rad fan bracket (which obviously is mounted on the end tanks, no?).

adam c

iTrader: (2)

I thought I answered your question.

These are the 12 to 15.5 psi numbers


The "other numbers" I am referring to are the ones where I ESTIMATED that a RB duct and a K&N could produce 1/2 to 1psi increase in boost. I did not test for these results.


I sent you a PM telling you that I thought the tank on top of the fluidyne was 2" thick. The tank on the stock radiator is also 2" thick. I measured it. I would GUESS that the intercooler won't be lifted any higher with a fluidyne radiator. I'll start a new thread to see if anyone has done this.

Adam

paw140

It is my understanding that the ECU does not limit boost to 10 psi. The boost is limited by using a restrictor 'pill' in the wastegate and turbo control actuators. The pill is inside the vacuum lines for these actuators. When people talk about installing a 'Home Depot' boost controller, basically what they do is tap into these lines and install an adjustable needle valve. With this adjustment, you can limit boost to 10 psi.

kento1

Yes, the HD boost controllers bypass the wastegate spring that is preset to 7 psi, and pills modify the flow that reaches the wastegate actuator. But the wastegate duty solenoid is controlled by the ECU, and definitely affects boost. Otherwise, I would not have experienced an increase in boost (3 psi) simply by installing a Pettit ECU with no other changes.

adam c

iTrader: (2)

My "HD" boost controllers were installed per rob robinette's instructions. They only replace the two vacuum/boost lines with the pills. The wastegate spring is not effected.

Your petit ECU will have some preset characteristics. One of which will be to allow a higher boost level. My M2 ecu helped to increase my boost from 10 to 12.5. I installed a DP at the same time as the ecu, which accounts for some of the increase.

Adam

kento1

Sigh.....Adam...your HD boost controllers are bleeding off the pressure that the actuator sees, otherwise the wastegate spring will hold the boost to 7 psi; the pills in the lines are there to restrict flow to the actuator, hence the 10 psi max for the stock setup. So yes, the wastegate spring IS affected.

The ECU does affect boost level, which is what I was explaining to paw140. The "preset characteristics" you're mentioning are changing the wastegate solenoid duty cycle in the ECU. This is why my boost level increased by just installing the Pettit ECU. So the stock ECU does try to keep stock boost levels to 10 psi (otherwise fuel cut hits at 12-13 psi, depending on gear and rpm).

Capische? Wakari mas?

adam c

iTrader: (2)

What I meant to say was that the HD boost controllers do not BYPASS the wastegate spring.

I think we need to get a translator/mediator. Comprende??

Kento

Uhh...si...actually, the wastegate spring IS being bypassed when you bleed off pressure to the actuator, 'cuz the wastegate spring is clamped on to a 7 psi max setting all the time...

OK, done with this thread. Cya!