20 psi with pump gas how much timing?
 

Hi guys I need to know how much timing I need for 20 psi with pump gas

I was runing my fc at 16 psi with 10 on the leading and 10 split and it ran perfect but I put it on 15 on leading and 10 split and boommm ... go to home with one rotor ...

damm atkins are made of butter I only like them because they dont damage the housing or rotors when broke

that was with 8.5:1 rotors 93 pump gas 10.5 10.3 a/f ratio

I want to put it at 20 psi with pump gas but dont know how much timing

any tips or info would be apreciated

the atkins seals arnt very strong.

you should try the SCR seals.

www.southcoastrotary.com.au

Im a dealer for them. they are a great seal. when you push them too hard they simply bend on the ends so they dont damage anything in the process.

they cant take a heap more punishment then mazda, atkins etc.

as for your timing. 20psi is alot of boost on 93 octane fuel.
if i had to run that boost id stay around 5-6 degrees.
If you want to push that much boost into a rotary. id suggest you got get some water injection and crane hi-6 cdi boxes. and then you screw another 4-5 degrees of timing in their safely.

pm me with prices

The Atkins seals are perfectly fine. They break-in easily, they don't damage components, and they can take the horsepower. The problem isn't the apex seals Jesse -- it's the attempt to run so much boost (and hence, so much load and heat) on a sub-standard fuel.

B

You are correct partially. But with a stronger apex seal which can tolerate more heat, a steel that has a higher plastic deformation point and has a higher HV you can push the engine harder. yes you are limited to an extent but the SCR seals will allow you to push it more.
the atkin seals have a high percentage of chromium making them very brittle.

I know but a lot of people here run 20 to 25 psi of boost with bridge port
engines on 93 pump fuel maybe my a/f ratios are not accurate

I got my microtech wideband mounted on the stock o2 location it can give me false rich ratios???

Drop the a/f ratio to 10.0.
See how you go.
Do you have egt sensors in your manifold? put some in.

see what your egts are. they will be the answer to how much timing you can put in an engine.

Perhaps you guys down in PR are blessed with better gas than in the 'states, but it's not something we can get away with here in any long-term capacity. Doing short stints on that much boost might be possible, but nothing with respect to flat-out running in 1st, 2nd, 3rd, and 4th gear, as say what would be typical for a 1/4mi drag run.

B

That's absolutely too rich and is to the point of beginning to blow spark out. So much fuel is being wasted in an attempt to keep itself from spontaneously blowing up -- what's the point? Perhaps this is a philosophical difference, but I can't stand to see having to upgrade a fuel system, potentially an ignition system (with respect to coils in this case), just to run a ridiculously rich mixture, well past the point of where power and torque is being substantially sacrificed, just to gain an arguably marginal increase in "reliability" all the while using junk fuel in the first place. Makes no sense to me.

I absolutely do not recommend this approach. There are better options that yield a considerable improvement not only in power output but also reliability.

B

I don't buy this for a second. What you're implying here rx72c is that other seals sans the SCR seal are inferior in a sense that they'll fail earlier, from a structural point-of-view, with respect to some sort of heat due to engine load. Like any other claim, especially one that's used to promote a product, prove it. Show some evidence as to why we should buy your gee-whiz, super ninja apex seal. What kind of power and load levels are talking about here? What kind of heat? Just about every other apex seal out there that has long-term use (the various stock Mazda units, Atkins, etc.) all work just fine on many high-powered setups far beyond anything we have.

Been there, done it, with the Rotary Aviation apex seal. What results did their flooding of the market in late '03 yield? Torn up rotor housings and excessively worn apex seal grooves to name two just off the top of my head. Metallurgically speaking, you could be right, but so what?

There's no such thing as a magic apex seal. The reason why apex seals fail is because people use convenient, cheap, and easy-to-get junk gas while trying to attain and maintain a high-output power level of the engine. If we all ran the proper kind of fuel, the question of apex seal reliability would be a moot one.

If it ain't broke, don't fix it.

B

A couple more things I wanted to add -- With a good fuel, I normally run 15-17*BTDC advance on the leading and a bit more aggressive split at that boost level, yet I have no issue and haven't had issue. The problem here, assuming there's no EFI installation problem, technical issue with the car, or an issue of running too hot a plug, is the fuel that's being used. That kind of pump fuel, which has questionable stability in the first place, isn't meant for that kind of load on any consistent basis. Pump fuels change from manufacturer to manufacturer, station to station, and pump to pump. In contrast, with race fuels and alcohol, you get what you pay for -- If you are purchasing 10 gallons of C16 (VP Racing 117 octane leaded), you are getting what you're paying for; no questions. Race fuels are designed for higher loads and hotter internal temps. The culprit here is the auto-ignition temperature of a fuel -- in this case, pump gas's premature auto-ignition during the compression stroke -> kaboom.

B

If it's a Bosche sensor, quite possibly. If it's an NTK, highly doubtful. The Bosche sensor isn't known for being accurate or reliable in a high-temperature environment. Many people have attempted (with success) creating heat-sinks for the sensor just to try and combat this problem. The other answer for that particular sensor is to move it downstream the exhaust closer towards the end of the downpipe where the EGT's have dropped significantly enough to not warrant a problem. With the NTK sensor, however, it's a moot point. Which one are you running?

B

Mate. i dont want to get into an argument with you. but i have tuned plenty of cars and have tried most different apex seals.
pts , ra, nrs, scr etc.
scr isnt that best out of the lot.
for heat tolerance NRS is the best.
bang for buck, cant go past scr. i.e out of the steel seals this is the best.

with NRS seals you can get use cheap shitty junk gas and run serious timing with out any issues. This is because they can tolerate higher egts, and this is the result of running alot of timing on shit fuel.

with the scr seals, while not as heat tolerant as NRS seals, they can tolerate alot more heat the mazda, atkin, hurley apex seals. i have studied the 4 different metals and know their properties. SCR seals have the highest plastic deformation point out of the 4 metals.

im going to install the wb on the Y pipe and the egt 4" to 5" after the turbine and let you know guys

btw if I put the wb sensor right before one of the 2 exhaust mufflers it read the same a/f ratio? I mean reading only the half of the exhaust gases?

put your wide band around 8 inches away from the turbine rear housing, not after a muffler or a cat to get the most accurate reading.

BDC, why do you continue spreading this garbage ?
Not sure what you consider a high-output power level, but with the convenient, not so cheap and easy to get "junk" pump gas you could double the factory horsepower (~400rwh @~14psi)......an easy task for most tuners and most rx7 owners will be satisfied with that level.

Anytime you increase boost you're obviously getting closer to that ugly threshold called detonation but most "good" tuners should be able to tune for max power while still maintaining a safe tune away from that threshold ragardless of gas.
I've personally run up to 20psi on 93octane for years(dynoed 48xrwh @18psi) and most tuners have no problem with 17-18psi with the proper mods.
It's a matter of adjusting ignition timing to keep up with a fast fuel burn rate and a slight richer condition to offer a cooling affect.....nothing special.

Care to explain why people still break seals on race gas or Alcohol ???
....maybe same reason when they break on pump gas !

Apex failure is usually a result from overboost, bad tuning, lack of fuel and over heated air/engine and NOT from pump gas alone !!!
With all these aftermarket "softer" seals available for half the price I've seen apex failures actually go up, but people are ok with it since they usually cause no or little damage internally....go figure.
Atkins doesn't even recommend their seals for high boost (15+psi)

For those true "high-output" setups straight race gas(C16) or Methanol/Alcohol is the only way! .......Simpe and one less variable to worry about.

JD

Exactly!
Some people will never get that point John. Both you and I know better and have being doing so for a long time.
It seems a lot of people have the belief that because they can't do it then no one else can. The sad part is that instead of listenning to the ones who have and try and learn from them they continue to spread garbage and misinform.
I've personaly ran 20 and even 22psi on special combinations on straight 93 octane pump fuel without any problems what so ever. There's no magical ignition number or AFR that's going to make that happen. It's called tuning the entire combination to suit.
RX72C has made very valid points about the effects of different apex seals on tuning. There's a reason why I don't use and reccomend Atinks seals and that's because it does not work for my combinations and that's it. I would use the factory apex seals over Atikins any day and that's my choice.

Interesting reading. again

Did you know F1 engineers back in the day specified 40~50% over stoichiometric for maximum power running during qualifying? even with "rocket fuel".

I dont care for arguments with anyone anymore over this stuff but to answer the posters topic *from my experience*

(for high loads mid to high rpm)
* Run AFR from 10.2 to 10.8:1
* Run 12 deg advance and 8 deg split (maximums)
* B10EGV plugs gapped to 0.6mm

And you will be fine on pump fuel only with that comp ratio, have done it many times.
If you want to run it leaner or run more advance (asuming the engine is healthy and make compression and resulting power) I'd suggest water injection, I have a car that that runs 600rwhp, 8 deg advance and 10.0:1 AFR on pump gas and Water Injection with bullit proof reliability...... I have a dyno sheet posted here somewhere of it with the boost falling off and it made 578rwhp on 18 psi (normaly runs 21psi on street).

have fun with it :)

p.s. its a falicy that you need excessive advance on a rotary engine, there are qualified people on this forum who can vouch for this (some have replied in this thread) others are too busy runing professional engine dyno's ;) one such person is Frode he used my setting on his bosses engine dyno for his T2 motor and they used my base line parameters and found minor gains in power by running outside of them (5 bhp in 580 !) so decided upon sticking with what was recommended after suffering previous engine failures. His car still runs today as do all of my customers cars that make geniune power on pump fuel (or race fuel for that matter *be it pure meth or C16*!!!).

the only time you ever need excessive ign advance is when you have a shit set up *manifold or engine* that is restricting how much stuff is inthe combustion chamber at any given moment and when this is reduced you can run stupid levels of advance because for the simple fact there is not enough in the chamber to generate heat or power, its a pretty simple situation to understand. This is more common in top level NA rotray racing where dreamers put on the latest horses cock styled bandwagon train jumping manifold and require 35 deg of advance to make it produce power ! v's the semi normal style that uses 22 deg advance and makes the same power at 2000rpm less peak speed :) :) :)

rice is on the money / I stop at 17/18psi -12deg no split

ive personally run 20 psi on a stock ported motor with 93 octane fuel back when i was running Skip Gorman's anti detonation device.... lol... (yes i was a guinea pig) The engine lasted a good 2000-3000 miles with the single turbo setup at that boost on top of the 7000 miles it already had on stock turbos before it broke due to some wiring issues when i was only running about 13 psi... I wish i could chime in and tell you about what timing i was running because i really dont know...

I was talking with a local tuner about my set up and he said that dosent matter if I use pump gas he said the a/f ratios are the key I tell him that I was running 10 leading with 10 split and 10.5 a/f ratio and he told me that he cant run 15 on the leading is to retarded for him


all my tunning knowledge is from this web site and now after I talk to him I see that there are 2 diferent ways to tune


# 1 the more comon in this site and the one that im using ... 10.5 af ratios with not more than 10 on leading and not more than 18psi . thas why a lot of guys cant run more than 18 psi on pump gas because the overheating and detonation 10.5 is not enough for pump gas I think


#2 the less used and more efective for high boost street cars = lower a/f ratios than 10.5 maybe 9 or 8 or 1100 to 1200 egt?
and 20 dregrees on leading and 20 to 25 psi of boost .

correct me if im wrong but I think that this is what this guy is doing
and with atkins seals!

he tuned some fast street cars here all with pump gas
a semi peripheral TII w T76 10.9 other TII steet port 11.7 with h3 turbo and other 11.9 street p with hybrid stock turbo h3 Ill try to post a video

btw thanks for the info ... crispeed rice racing boosting seven bdc and all that have posted ...you guys are posting a lot of usefull info

thanks you

mine is bosch it comes with the microtech wb

Once you go 55+% over stoichiometric (60% is the limit) you will start to increase the tendancy to knock which is well documented. 40% rich is very common with timing figures I gave you.

So basicaly you can dump more and more fuel which will allow you to make higher power and take much heat from the engine and turbo......... you can have too much of a good thing though ;)

When you get sick of wasting so much fuel or needing to run other fuels then you can do the same by adding water injection :) :) :) and it will add a margin well over what you could do by fuel dumping alone.

what water injection kit you recomend to me? it need to be calibrated for a specific boost amount ??

when atkins blow