running lean fwdp stage 5

[spiro440]

I just came back from the track, what a blast! During my last laps the vacuum hose that is plugged to the intake pop off. The car ran like crap of course. Got to the pits plug the hose back and everything was fine. On my way back home it started sputtering like it was missing fuel. Got home changed the distributor cap and wires. Ran a little better but he plugs where white. When I floor it the best I get is 13.6 on the wideband. I don't have any fault codes. At idle I get 14.8, Looked for any vacuum leaks and all is good.
The last laps where done with my brother at the wheel chasing a Z06. I had my eyes on the wideband all the time, and it alway hovered around 11.3 to 11.8. What could have happened! I still get good boost and the car does not ping. The fuel pressure is set at 42psi and at boost I get 60 psi.

[raccoon]

with the map unplugged it might of gone super rich and fouled your plugs. take a look at those.

---------- Post added at 04:15 PM ---------- Previous post was at 04:14 PM ----------

edit sorry i didnt read.

[spiro440]

I removed them and they were white. Clean and white.
other ideas?

[turbovanman²]

Why is your fuel pressure set so low?

Unplug the battery and clear out the memory and see what happens.

[bakes]

did you blow the FPR vac of too by chance?

[Directconnection]

Why is your fuel pressure set so low?

Unplug the battery and clear out the memory and see what happens.

What he said. If the vacuum/boost source pops off and it is part of the MAP, it will go into limp mode until you reset the computer via disconecting the battery for a short while.

[spiro440]

Why is your fuel pressure set so low?

Unplug the battery and clear out the memory and see what happens.
Once I got the cal. I went to the dyno to optimise my adj. cam gear and set the fuel pressure for the best results.
I did clear the memory and nothing.


did you blow the FPR vac of too by chance?
That was checked to.
I also checked the timing belt to see if it jumped. That was good also. I went throught all the vacuum lines and found nothing.
The only thing I noticed was one of the plugs wires terminal was bent and loose on the spark plug, but why would I be running lean at full throttle??
The wide band is new since friday.

[glhs727]

do a fuel pressure test, so what the fuel pressure does when you get into boost and the fuel goes to 12+, is the pressure dropping or rising with boost. If dropping that would explain your higher a/f's and your fuel pump is going out....<br>If the fuel pressure holds, or rises like it should them you have an issue elsewhere. Start with fuel pressure and go from there....

[turbovanman²]

Fuel pressure testing 101-


First off, hook up a pressure guage to the shrader valve or tee in at the rubber line-engine cool and engine off.

Start the car and note fuel pressure, it should be around 50 or a bit less, unhook the vacuum line to the reg and it should go up to 55 psi. Now shut the car off and watch the fuel gauge, the pressure should stay. If not, pinch the pressure line-if it drops, you have a bad FPR or leaking injectors, if it holds, the check valve the in fuel pump is bad and the pump should be replaced.

Make sure the key is off, jump 12 volts to the coil + terminal, a fused jumper wire is best but a piece of wire will work just fine.

Now, you should be reading around 55 psi, now squeeze the return line, the pressure should jump to around 90-100 psi. If not, the pump is no good. You can check the FPR if you have a vacuum pump if not, the above test works.

These tests assume you have no leaks and a clean/newish fuel filter thats not plugged up.

If you have an amp clamp and a lab scope, you can check the brushes by looking at the waveform pattern, it should look like a nice sine wave.

[spiro440]

do a fuel pressure test, so what the fuel pressure does when you get into boost and the fuel goes to 12+, is the pressure dropping or rising with boost. If dropping that would explain your higher a/f's and your fuel pump is going out....<br>If the fuel pressure holds, or rises like it should them you have an issue elsewhere. Start with fuel pressure and go from there....

I got 42 psi at idle and 60psi at 18psi of boost
Secounds before popping the vacuum line everything was good. Full boost down the straight - brake hard - hairpin - full boost- hose pop!
The car at idle is great 14.8 a/f as soon as it gets out of vacuum (above 0 psi manifold pressure) it sputters. When I mash it, it will rise in boost and stop sputtering. And it runs lean.
No pingging with 94 octane.

---------- Post added at 05:24 AM ---------- Previous post was at 05:21 AM ----------


Fuel pressure testing 101-
I wil try it, pretty sure it's good.
Never assume... I will do the test as soon as I get back.

[Force Fed Mopar]

Bad fuel injector o-ring maybe?

[spork]

You might also check all hose couplers. Make sure none or loose or have any small tears in them.

[spiro440]

Fuel pressure testing 101-

Fuel pressure testing 101 done and gets a passing score!


Bad fuel injector o-ring maybe?
All O-rings new


I will go at it again, I must be missing something stupide.
The car does not sputter any more. but it still runs lean.????

[Force Fed Mopar]

Running race gas? That kills some WBO2 sensors.

[spiro440]

Running race gas? That kills some WBO2 sensors.
Nope, pump gas 94 octane, brand new wideband O2 sensor.

[turbovanman²]

Fuel pressure testing 101 done and gets a passing score!




Check volume, one pint in 30 sec minimum.

[black86glhs]

Good call. You would think if pressure is good, volume would be. I've run into this before a couple times.

[spiro440]

Check volume, one pint in 30 sec minimum.

2 pints in 20 sec.
I did notice that the a/f was at 12.3 at idle with the return hose in the bucket and changed to 14.8 once the return was plugged back. If that is any info ou can use!!
I just ordered a new fuel filter for what it's worth. The one that's on now has only about 2000 miles on it.

[4 l-bodies]

Spiro where is A/F when it's is sputtering or when it used to sputter, or in other words A/F during transition into boost? You might throw another HEP and see if it acts any different. A bad HEP can cause you to to lose some hair (lol). The TPS might have developed a bad/worn spot on it where it runs lots of the time 2500-3500 RPM. Seen that before. Maybe try temporarily cranking up fuel pressure and test drive again to see if A/F changes at WOT. Have any way of testing spray pattern and flow of injectors? Can you monitor spark retard (DRB) on each cylinder while driving ?
Todd

[spiro440]

I was going to change the HEP but changed the wires and cap instead since I found a bad terminal boot. That seems to have solved the sputtering. When I accelerate hard the a/f dips to 15.xx and slowly makes it's way to 13.6 and that's the best I get. Thought about the tps, but at full throttle it should send a signal to go full rich. I'm wondering about the 02 sensor. I know it's a narrow band and just toggles from lean to rich, Usualy a should get a code for the O2 and it should also go rich. No way of checking spray patern.
Keep in mind it was running great until the hose poped. How many things could that screw up?? I do have a DRB that my friend gave to me. I never used it, He was supposed to come over but the beer usualy gets in the way!!

[turbovanman²]

Hmmmmmmm, that doesn't make sense, well anyhow, that means the return line isn't the problem, or the pump.

So that leads to a map/sensor problem or the cal mysteriously wigged out. Try turning up the fuel pressure and see if the lean condition goes away.

[spiro440]

I will try the new filter tomorrow when I get it. If that doesn't help I will go through all the hoses again once more and if all fails, turn up the pressure.

Would the cal. fry if one of the plugs wasn't working properly.?

[black86glhs]

I'm wondering about the O2 sensor also. Try another one if the filter doesn't do it.

[spiro440]

Hope I have one somewhere and also going to try another MAP.
I will keep you posted.

[turbovanman²]

Sounds good on the filter.

Plugs being bad taking out a computer, haven't heard of that one yet unless the wire falls on the wiring and sends current to it, lol.

Oxygen sensor is ignored at WOT so that shouldn't affect it, especially considering its ok not at WOT.

[spiro440]

I have a feeling that the map is off it's calibration. Everything seems fine until I floor it. The computer seems to want to bring the a/f down but stops at 13.6.
I always thought that it's either good or bad. But now I'm wondering if it's just off if that's possible. I'm I overthinking this??
I would go for the map before the 02.

[bakes]

I have seen oil get pushed into the the Tps sensor and do wierd things .
do you have a spare 3 bar map to swap in ?

[Force Fed Mopar]

Are you running a MBC?

[spiro440]

I have seen oil get pushed into the the Tps sensor and do wierd things .
do you have a spare 3 bar map to swap in ?

No spare 3 bar map unfortunatly, going to have to purchase one, I will look for a tps.
Thanks


Are you running a MBC?
No, just what the computer gives me. Being weak and boost is addictive, I would probably turn the MBC up. The less control I have over boost the better!! LOL!!!!

[glhs727]

do you have a scan tool? take the car out and check both tps and map voltage.... if one is out of it's range, change the sensor.

[shelbymonster]

can a fuel pump can give good pressure and not enough volume ? i beleave so , after doing some track time i would beleave that all the loose stuff in the tank may have pass the fuel sock and clogered the fuel filter ...

[Juggy]

can a fuel pump can give good pressure and not enough volume ? i beleave so , after doing some track time i would beleave that all the loose stuff in the tank may have pass the fuel sock and clogered the fuel filter ...

thats what happened to my car. it ruined a complete season of racing trying to decipher the problem. 12.0@115 on 40psi fuel pressure 20 psi boost 5-6 months straight....oopsy.

[Force Fed Mopar]

No spare 3 bar map unfortunatly, going to have to purchase one, I will look for a tps.
Thanks


No, just what the computer gives me. Being weak and boost is addictive, I would probably turn the MBC up. The less control I have over boost the better!! LOL!!!!

Maybe the wastegate or baro solenoid is stuck open and causing a leak.

[ol"blue]

Wow please keep up the info i am having the exact same problem no stage 5 but same stuff,very strange will post back what i find.

[spiro440]

Had time to work on it today.
I got a new map sensor and did not help. (100$ for spare parts) and swap another TPS sensor.
I plugged a DRB II and got the readings from the map which idicates 11.6 in.hg and 12.5 at WOT full boost. My gauge shows 17in.hg and 18 psi. I'ts my first time using a drb II, pretty cool tool!
I also plugged my gauge directly in the same line as the map and the values where the same 11.6 at map and 17 on gauge. I guess the computer is not reading the inputs correctly, It seems to be off by 6. The O2 sesonr goes rich at full throttle, the TPS indicates 3.69v. That seems to be working fine.
I don't want to turn up the fuel pressure as that would be ignoring a problem.
Now where do I go from here??

[4 l-bodies]

Spiro,
3.69 volts seems sorta low to me for WOT. I think it trips high code @ 4.7 volts. I would double check TPS input voltage (should be 5.0 volts) and check DRB with key on engine off and see if it is telling you TPS is at 100% @WOT. I believe it gives you a voltage and percentage correct?
Beginning to sound like ECU went bad. Is this still a LM vehicle? I still would crank up fuel pressure temporarily to see if A/F comes back down. Certainly not going to hurt anything doing that.
Todd

[spiro440]

I'm new with the drbII. Only been using it for 30 minutes!!
I've got 88 electronics. I will see what else I can get as info and report back.

[spiro440]

TPS indicates 100% at WOT. I swap computers to see if the map would give me the same values. No change 11.8in.hg from the map and 17 on my gauge. I blocked the baro, no change. I turned up the fuel pressure to 54 psi and the car runs at 11.6 to 12.3 on the wideband. The car boosts 20psi and then drops a little. About 2psi more than usual. The cal is set at 18psi.
The map reads around 12.5psi at full boost. The car runs okay but does not seem to haul like before. I had a run in with an Sub Sti and a CSRT-4 on the highway. Didn't pull away like I used to, even with 2psi more. Anobody have other ideas?? Why is the map reading lower?

I will change the fuel filter tomorrow.

[shackwrrr]

TPS indicates 100% at WOT. I swap computers to see if the map would give me the same values. No change 11.8in.hg from the map and 17 on my gauge. I blocked the baro, no change. I turned up the fuel pressure to 54 psi and the car runs at 11.6 to 12.3 on the wideband. The car boosts 20psi and then drops a little. About 2psi more than usual. The cal is set at 18psi.
The map reads around 12.5psi at full boost. The car runs okay but does not seem to haul like before. I had a run in with an Sub Sti and a CSRT-4 on the highway. Didn't pull away like I used to, even with 2psi more. Anobody have other ideas?? Why is the map reading lower?

I will change the fuel filter tomorrow.

The drb automatically assumes that you have a 2 bar map, so the voltage that a 3bar puts out at 20 psi is the same as 12.5 psi on the 2 bar.

[spiro440]

Thanks,
That's good to know. Makes me feel better. I guess that should not affect the fuel and spark curve. Still doesn't explain why I'm running lean.
Any other test I can run? I'm still stumped!
I will change the fuel filter and see if I'm lucky.

[Force Fed Mopar]

Yeah if you have a 3-bar map the DRB map-related readings will be useless.

[bakes]

your are not running a Cat are you?

do a leak down test i had bad Ex. valves / seat screw me around like this 4 years ago

[spiro440]

your are not running a Cat are you?

do a leak down test i had bad Ex. valves / seat screw me around like this 4 years ago


No cat.
Leak down? Only have 3500 km on the build. I hope nothing is srewed up. I'll do that tomorrow too.
Cant' see why it would run lean, but ...?
It all started with a f.....ing vacuum hose that popped off the the intake manifold!!!!!!!!

[Force Fed Mopar]

Maybe the fpr isn't increasing the pressure with boost?

[spiro440]

Maybe the fpr isn't increasing the pressure with boost?

One of the first things I checked. It follows the boost for every pound. ( see post #10)

[spiro440]

Changed the fuel filter...... no change?!?!!!!!

[Force Fed Mopar]

Did you continue to run it hard after the line popped off? Maybe you burned the exhaust valves or something.

[spiro440]

No, when it popped off the car sputtered like crazy and I limped back at 20 mph to the pits and popped it back on and the car's idle dropped let it run to cool off and shut it.
I started looking at it again this morning went for a joy ride and decided to go gaz it up since it was empty, and now it missfires at 15 lbs.( i didn't even stop the car!) Hope it's just bad gas, but then again it usaully pings! Maybe a bad coil or something. Will empty the tank, refuel and see, then change coil and see, and then ..... .
Wanted to do a leak down, 3 kids to tend too will return to it later.

[ol"blue]

Well found my prob,adj cam gear backing it self 2 mark - set it back and car runs like a champ.hope you find the prob or maybe this helps either way gl.

[spiro440]

That's great,
checked that at the beginning (post #7). I will go back and check again and everything else as well.
Thanks

[spiro440]

Did you continue to run it hard after the line popped off? Maybe you burned the exhaust valves or something.



your are not running a Cat are you?

do a leak down test i had bad Ex. valves / seat screw me around like this 4 years ago

Did leak down #1: 2%, #2: 2%, #3: 4%, #4: 5%. Pressure used 100 psi for test.


Well found my prob,adj cam gear backing it self 2 mark - set it back and car runs like a champ.hope you find the prob or maybe this helps either way gl.

Double checked.

Will continue. Eventually I will get it. Got 2 months before SDAC!!!!

[Force Fed Mopar]

Maybe an intake gasket leak?

[bakes]

also if you Wb sensor is in th down pipe check for any air leaks into the exaust post turbo.

[turbovanman²]

What's the compression?

Did you replace the fuel filter yet? You keep saying you will but never do, :eyebrows:

I damaged my motor blowing off a vacuum line, leaned out and I pinged it, :mecry:

[spiro440]

also if you Wb sensor is in th down pipe check for any air leaks into the exaust post turbo.

That's an idea. Car does not sound like it used to. Maybe I'm paranoid


What's the compression?

Did you replace the fuel filter yet? You keep saying you will but never do, :eyebrows:

I damaged my motor blowing off a vacuum line, leaned out and I pinged it, :mecry:

Didn't take compression. My gauge is broken. Will have to get a new one. Did the leakdown instead.
For the filter.... post 46:eyebrows:
I sure hope I didn't hurt it, put to much money into it.


I closed the gaps on the plugs to see if that would change the missfiring issue (.030). No change. Just an extra test before dumping the fuel and changing the coil.
Car runs good until 15 psi and then still missfures.

Will report back. Pretty busy for next few days but i will try to put in a little work.

[shelbymonster]

That's an idea. Car does not sound like it used to. Maybe I'm paranoid



Didn't take compression. My gauge is broken. Will have to get a new one. Did the leakdown instead.
For the filter.... post 46:eyebrows:
I sure hope I didn't hurt it, put to much money into it.


I closed the gaps on the plugs to see if that would change the missfiring issue (.030). No change. Just an extra test before dumping the fuel and changing the coil.
Car runs good until 15 psi and then still missfures.

Will report back. Pretty busy for next few days but i will try to put in a little work.

i did have couple oil filled coil giving out on me before , and they do missfire after 3000 rpm , i went with a later coil after that and never had a problem after that

[spiro440]

No progress!
Dumped all the fuel and changed the coil........ still missfires.
Will change the Hep tomorrow.

So far did:
Checked fuel pressure
Checked fuel pressure rise with boost
Checked fuel pump (flow and pressure)
Checked baro. for leaks
Changed MAP
Changed TPS and verified 100% signal at full throttle
Changed fuel filter
Checked all vacuum lines
Checked timing
Checked cam timing
Checked adj. cam if slipped
Did a leak down test

Once all this was done I decided to turn up the fuel pressure to not run lean and figure it out before I get a faillure. Once figured out I guess it would run rich. (Safer)

Fueled the car up and now it missfires,
Changed fuel
Changed coil
Reduced spark plug gap

Any other Ideas I maybe missed?

[168glhs1986]

Did you say you verified computer was fine? How about putting in a Stage II cal and a 2 bar map, grainger it up to 18 psi and see how she runs?

[spiro440]

Did you say you verified computer was fine? How about putting in a Stage II cal and a 2 bar map, grainger it up to 18 psi and see how she runs?

I have a s60 around. I had put it in to compare values of the sensors but did not take it for a run. I will do the swap and run it at 14 to see what gives??? and then 18.
I have nothing to loose.
I will put the new HEP first and then the s60 and report back.

[turbovanman²]

Maybe I missed it but when did it start misfiring?

[spiro440]

Maybe I missed it but when did it start misfiring?
I had just brought up the fuel pressure and took it for a 60 km test run. (pulled a run with a wrx sti and a CSRT-4 on the highway) Did not feel as fast but at least it wasn't running lean.
Was low on fuel, gased without turning it off and that's when it started. At the first full throttle stomp!!!

[168glhs1986]

I have a s60 around. I had put it in to compare values of the sensors but did not take it for a run. I will do the swap and run it at 14 to see what gives??? and then 18.
I have nothing to loose.
I will put the new HEP first and then the s60 and report back.

Even better, then you can run the 3bar map. If it is the computer, I vote for Big Stuff 3 installed by Slowe Racing!

[Force Fed Mopar]

Maybe the valve springs got weak? Are they stock?

[bakes]

No progress!
Dumped all the fuel and changed the coil........ still missfires.
Will change the Hep tomorrow.

So far did:
Checked fuel pressure
Checked fuel pressure rise with boost
Checked fuel pump (flow and pressure)
Checked baro. for leaks
Changed MAP
Changed TPS and verified 100% signal at full throttle
Changed fuel filter
Checked all vacuum lines
Checked timing
Checked cam timing
Checked adj. cam if slipped
Did a leak down test

Once all this was done I decided to turn up the fuel pressure to not run lean and figure it out before I get a faillure. Once figured out I guess it would run rich. (Safer)

Fueled the car up and now it missfires,
Changed fuel
Changed coil
Reduced spark plug gap

Any other Ideas I maybe missed?

Dick had wicked missfire and it turned out to be a i shaft gear going , i think Cory had the same thing too. I just didnt effect the spark timing but the fuel injection timing as well just something to check .

[trannybuster]

Same issue gave me fits also,until it finally failed, I knew it had to be timing but never had an intermediate fail or realing thought they had issues.

[spiro440]

Maybe the valve springs got weak? Are they stock?
Brand new heavy duty ones. Put them in when building the block with pt lifters. Got 3744 km on them.


Same issue gave me fits also,until it finally failed, I knew it had to be timing but never had an intermediate fail or realing thought they had issues.


Dick had wicked missfire and it turned out to be a i shaft gear going , i think Cory had the same thing too. I just didnt effect the spark timing but the fuel injection timing as well just something to check .

I was thinking the same thing yesterday. I had 3 give on me on this block.! How do I check besides removing it?

[Force Fed Mopar]

Take the distributor cap off and see how much play is in the dizzy/oil pump drive.

[spiro440]

Don't want to get to excited but I think it is solved. I only had a few minutes today and decided to just swap my s60 computer. Well at low setting it was good!!! then I hesitated to go to high boost since I don't have 100 octane fuel....... the heck with it! I flicked the switch and the car just woke up. Steady boost and rich at 10.8 to 11.0. I got nervous and let go did not want to detonate (no knock & o2 feedback). Tried it again a little longer listening for a ping....nothing. Put it back on low and gave her a run for my personal therapy. And like a good piece of a.. I could not get enough and hit the high boost and brought it to over a 100mph hit the brakes tried it again loading it from 35mph in 5th till 100 again. Did this for 20 minutes. Nothing the car runs great on 94 octane. Mind you rich but good. I will go for a run again tomorrow just in case it was luck. Once it is confirmed that it is good I will put the other computer back just to double check. And then rip off the toggle switch on low setting before getting into trouble.

I do not understand how can a computer just go tits up??
Lose it's calibration?:confused:

[trannybuster]

More like you have a connection issue, one of those many pins is sub par. Clean and make sure they are tight.

[spiro440]

More like you have a connection issue, one of those many pins is sub par. Clean and make sure they are tight.

Pins on the connector or the chip?

[168glhs1986]

Don't want to get to excited but I think it is solved. I only had a few minutes today and decided to just swap my s60 computer. Well at low setting it was good!!! then I hesitated to go to high boost since I don't have 100 octane fuel....... the heck with it! I flicked the switch and the car just woke up. Steady boost and rich at 10.8 to 11.0. I got nervous and let go did not want to detonate (no knock & o2 feedback). Tried it again a little longer listening for a ping....nothing. Put it back on low and gave her a run for my personal therapy. And like a good piece of a.. I could not get enough and hit the high boost and brought it to over a 100mph hit the brakes tried it again loading it from 35mph in 5th till 100 again. Did this for 20 minutes. Nothing the car runs great on 94 octane. Mind you rich but good. I will go for a run again tomorrow just in case it was luck. Once it is confirmed that it is good I will put the other computer back just to double check. And then rip off the toggle switch on low setting before getting into trouble.

I do not understand how can a computer just go tits up??
Lose it's calibration?:confused:

So how does the guy who knows the least about cars suggest the fix that might have fixed the problem.....beginners luck I guess :lol:

On a proven fresh build, I just had a hunch it wasn't mechanical. Hopefully you'll get it hummin before your next track session. Congrats and keep us posted.

BTW - Time to send the Red Baron down the Slowe Racing for a Big Stuff 3 install :eyebrows:

[spiro440]

So how does the guy who knows the least about cars suggest the fix that might have fixed the problem.....beginners luck I guess, haha.

On a proven fresh build, I just had a hunch it wasn't mechanical. Hopefully you'll get it hummin before your next track session. Congrats and keep us posted.

When the obvious doesn't do it go for the not so obvious! :thumb:
I'm keeping my fingers crossed till tomorrow, and then if I have to chug race fuel to the events so be it! Even at 100 bucks (that's canadien) for 5 gallons.

[168glhs1986]

When the obvious doesn't do it go for the not so obvious! :thumb:
I'm keeping my fingers crossed till tomorrow, and then if I have to chug race fuel to the events so be it! Even at 100 bucks (that's canadien) for 5 gallons.

Maybe sometimes it's a good think not to know how cars work....because the computer seemed the obvious thing to me.

$20.00 per gallon, wow. Do you think you need race gas to run it on high boost? Or how about a blend? I wonder if anyone has run the Super60 computer on high boost with 93+ octane?

[spiro440]

The s60 has a very agresive spark curve and in return needs a higher octane to keep from detonating. Combustion is supposed to be done in a controled manner. The s60 not having a knock sensor to ease things back(retard timming and lower boost depending how the cal is set) may loose control of what is going on. We have all purchased fuel from a station and have the car pinging afterwards. With high boost and no back up protection just makes me uneasy.
Maybe I could get away with it, I did it for two years with just adding octane booster ( 60 point rise) making it a theoretical 100 octane. It was an old engine and I wanted a reason for rebuild.
I guess a Big Stuff 3 would solve this:eyebrows:

[168glhs1986]

I guess a Big Stuff 3 would solve this:eyebrows:

I heard that!

[Force Fed Mopar]

BoostButton E85 cal ;)

[turbovanman²]

So how does the guy who knows the least about cars suggest the fix that might have fixed the problem.....beginners luck I guess :lol:

On a proven fresh build, I just had a hunch it wasn't mechanical. Hopefully you'll get it hummin before your next track session. Congrats and keep us posted.

BTW - Time to send the Red Baron down the Slowe Racing for a Big Stuff 3 install :eyebrows:

I said it way back in post 21, :p


The s60 has a very agresive spark curve and in return needs a higher octane to keep from detonating. Combustion is supposed to be done in a controled manner. The s60 not having a knock sensor to ease things back(retard timming and lower boost depending how the cal is set) may loose control of what is going on. We have all purchased fuel from a station and have the car pinging afterwards. With high boost and no back up protection just makes me uneasy.
Maybe I could get away with it, I did it for two years with just adding octane booster ( 60 point rise) making it a theoretical 100 octane. It was an old engine and I wanted a reason for rebuild.
I guess a Big Stuff 3 would solve this:eyebrows:

Most octane boosters raise the octane very little, something like 3 real points, they are virtually useless. Add Toluene or run alky. Search google too, someone did a really good test on octane boosters.

[wallace]

BoostButton E85 cal ;)

He does e85 cals?

[ShelGame]

He does e85 cals?

I've done a couple...