How much boost is too much boost

[Ondonti]

Good tune, careful use of the spark map that works in conjunction with the fuel octane available...you can do a lot of things as long as the longblock is physically capable of holding the abuse.

One of my concerns about E85 analyzers is that I thought some require all fuel to flow through the device. This kinda bothers me in a restriction sense. I was thinking since I am using dual fuel feeds I could just analyze one line and that would be a lot less restriction then someone running the same amount of fuel through one line.

Megasquirt, Proefi, newer AEMs all have E85 flex fuel setups. I have had no reason to care yet.

[Reaper1]

You beat me to it. I'm a fan of actually knowing when you're octane limited. I think I'm one of the few who still thinks that an EGT gauge is really helpful in finding where that point is. If you know the point at which you don't want to go beyond temp wise it's pretty easy to see when you can't pull any more timing. Pulling ign. timing will raise EGTs and you can only get so hot even at really numerically low AFRs before things get melty. IIRC I saw a 300* difference in EGTs at cruise in my old Omni by only changing from a stock 87 TII cal to an 89 MP TII timing map on the same cal. Once you get a feel for how your motor responds to the boost it's not bad at all to know approximately where you need to take the timing.

On the mechanical front You've got to stick with people in the know just the same as the target EGT. It's great that Cindy was able to chime in with a good answer there.

I agree that an EGT is a vital thing to monitor, especially while tuning. It can tell you all sorts of things if you understand what you are looking at. Before O2 sensors were even invented this was how engines were tuned (along with plug reading). Airplanes STILL use EGT's to get their engines running the way they need to. If the guys that are doing the pylon racing and such rely on this information to get the most out of their airplane and keep them in the air while not blowing the engine to bits, I think it's probably just as important for a car engine.

[85boostbox]

Any good tuner will strictly tune off of EGT temps. Period.

[Force Fed Mopar]

Any good tuner will use any good info they can get...

[Reaper1]

Any good tuner will use any good info they can get...

I agree. Paring EGT's with O2 readings really help make things faster.

[Shadow]

Just to throw a wrench, I've never used an EGT gauge and I never will! lol

[wallace]

I use the buret you can get it from summit to check the e85. I used the same station every time and the mix was dead on e85 in the summer and e70 in the winter. The tune on e85 is very forgiving. I had great success with it and found the limits of the cylinder heads. I dont think the fuel will be your limitation. Take it slow and be conservative as you make changes. Very interested to see how far you can go.

[glhs875]

Just to throw a wrench, I've never used an EGT gauge and I never will! lol

I have never used an EGT guage as well!!!

[contraption22]

Just to throw a wrench, I've never used an EGT gauge and I never will! lol

I have never used an EGT guage as well!!!

I still have one. I also have sun dial in my yard, but I use a wrist watch instead.

I've pretty much ignored my EGT since I've been able to monitor knock and A/F.

I'm sure an EGT would come in handy if you can datalog enough to see a pattern in your particular engine.

[Ondonti]

Any good tuner will strictly tune off of EGT temps. Period.

Because all good tuners apparently have an EGT vs every single possible fuel combo being injected? Very few cars use these effectively beyond 1/runner setups ensuring cylinder to cylinder happiness since I don't think o2 sensors want to be near the exhaust port (don't remember why).

EGT really only told me what I already knew except when spraying methanol. Then it let me know that junk was actually spraying something. I always knew that the richer my AFR got, the lower my EGT's would go (of course timing changes all that too).

It would require a huge bank of knowledge for EACH motor to really use EGT's. The moment you start changing the motor combination then that information would become less useful. A race team could get great use out of them as the try to keep replacement motors in the same "zone" as the old one and use the EGT as another way to detect/locate problems.

AFR is easy because you can shoot for a safe area. Most good tuners use a dyno to judge spark timing. Raise timing until power peaks or levels off or starts to gain very slowly, then adjust to an advance just before that unless you still have lots of knock resistance left in the octane of your fuel. Any other way of setting timing is educated guessing. You can track tune but its nothing like an eddy current dyno holding steady rpms and changing power outputs until timing is just right at each rpm point. That is like your computer vs an abacus. Lots of track/street tuners rely on excessive octane to make their tune safe or never quite get things perfect. I think I am too cheap to ever get things right. Dyno tuning doing "pulls" is not a lot better then track tuning and since that often doesn't put a lot of load on the engine, it might pop when going down the track on the top end.

[Force Fed Mopar]

FTR, I've never used an EGT either. I wouldn't mind having one though.

[85boostbox]

I have seen cars run good on a afr guage but egt skyrocket. I tune from egt personally. And a lot of tuners I know do the same.

[wallace]

You can get a good idea on timing reading the spark plug ground strap coloration and where the rainbow is. I was taught if the rainbow is in the elbow of the strap the timing is close and on the conservative side.. As it moves towards the end of the electrode you are getting more aggressive. This is just one more thing that you can use. Reading the plugs on the current tune (take pictures!) will give you a baseline to refer to as you make changes.

[85boostbox]

Just to throw a wrench, I've never used an EGT gauge and I never will! lol

You also run c16 when you run high boost. Big difference when it is the highest octane you can go without switching to a different fuel.

[Reaper1]

As has been said, unless a certain combination has a known EGT goal, then the actual number you are looking for will be different engine to engine. Some combos will run higher, some lower. It isn't a needed thing, obviously and just because you don't have one or have never used one doesn't mean you are doing anything wrong or are "less" of a tuner than anybody else. It just gives you more information to go on. Sometimes more information can actually be confusing, though so it's understandable if somebody chooses to stick with a method that uses minimal input, as long as they know how to use that input and it is meaningful input.

I hope to use individual probes to make sure each cylinder is doing what it's supposed to with a data logger. After I get things dialed in, then I'll just have a single probe before the turbine housing for a general monitor because at that point I'll hopefully know where the engine's "happy place" is. Anything outside of that will be cause to find out what's going on.

Yes, plug reading will do a very similar job, but pulling plugs isn't exactly my idea of fun in a parking lot or the side of the road. I'd rather look at a computer screen or print-out. It's personal preference at this point.

[Shadow]

You also run c16 when you run high boost. Big difference when it is the highest octane you can go without switching to a different fuel.

Correct, knowing my intention is to constantly Up the boost until the Holset makes no more power, I run as safely as possible by running the best fuel I can. Has Nothing to do with EGT's though.

I saw too many trust EGT's back in the day and every one of them melted their mtrs. From what I gather, it's because by the time the EGT is reading the zone that you Don't want to be in, your already there! Too late...........

[shackwrrr]

I had no idea there was a gauge that measures E85. That's awesome. That little nugget of information made this thread worth it. Thanks.

I had asked rob (shelgame) a while back if we could use the 0-5v output of one of those sensors (available at the junkyard cheap) to scale for ethanol on the fly and he said its definitely possible. I brought it up in the thread about the old tuneable ecu using the battery temp sensor as an additional input.

[A.J.]

I had asked rob (shelgame) a while back if we could use the 0-5v output of one of those sensors (available at the junkyard cheap) to scale for ethanol on the fly and he said its definitely possible. I brought it up in the thread about the old tuneable ecu using the battery temp sensor as an additional input.

I have a turbo Volvo friend who runs on E85 and keeps trying to get me to switch to Mega Squirt. I messaged him about the E85 gauge and he informed me Mega Squirt can compensate for E85. It would be awesome if we had the Chrysler ECU make on the fly adjustments for E85.

We really need to start a thread to start a pot to give to Rob for all the hard work he does for us with cals. As cheap as TM guys are, $5 (as a minimum) from everybody who uses Turbonator would add up quick. Another pot for wowzer for MPTune would be good too. I know I'm motivated by money.

[SactoShadow]

Obviously they aren't. They may, however be interested in some key parts we have on the shelf....

[Ondonti]

I am definitely a fan of the idea of spark plug tuning since its not going to be as vague as EGTs and having had a motor that burned so much oil that the plugs had to be preheated half the time and still might foul......I can deal with pulling some plugs.

but I don't really want to guess and check method everything I do with the tune on a car. blah to that.