gnx7

iTrader: (28)

I'm going to run a Holley EFI on an alum 5.3 setup, ported 5.3 heads, LS6 intake, baby 225/223 cam, running a GTS76 with billet wheel in a '69 Chevelle.

I don't really see people talking about using EGTs as a tuning aid? Is everyone relying upon WBO2 readings only?

End of the 1/4 WOT peak readings.....
What EGTs are people seeing on pump gas unleaded?
What about on e85?

What is considered safe and then a dangerous level on e85?

When I was into Buick GN's the tuning was very limited unless you went with an ACCEL DFI or FAST which wasn't within my budget. We mainly used EGT's for tuning. 1600* end of the 1/4 at WOT was what I used and then simply played around with fuel pressure to get there once I established my boost level. That was on 116 leaded race gas.

Forcefed86

iTrader: (4)

Little bit on it here.

http://www.raceone85.com/

Im in for better results though.

Reject

iTrader: (24)

good link

gnx7

iTrader: (28)

any input on this?

hellbents10

iTrader: (10)

Depending on probe placement, we generally shoot for 1450-1500 on E85 with a wedge engine.

rotary1307cc

iTrader: (5)

I should put a probe in my housing once since it is tapped.

It seems like mine must be very low. I run water/meth, ethanol, and a solid amount of timing


My hot pipes are aluminized steel 5 yeas old and still have all the aluminum there aside from the welds

Does the turbine for you ethanol guys look like this? My hot pipes look the same. No soot just really clean

87silverbullet

iTrader: (11)

I don't really think many people still use egt since you have so many other tuning variables to choose from. EGT works but it is a more crude way of tuning compared to what's out there now.

I used to run a turbo buick too and egt was used because of the primitive PCM in the car and unless you had some real bucks to shell out for a Fast or Accel it was pretty much all you had and the upgrade to a heated 5 wire oxygen sensor.

I remember seeing guys with obd1 scan tools to see what their car was doing or they had a scanmaster. You guys remember those things?

If I was tuning a supercharged or a high compression motor I can see having the 8 probe one in each primary setup. To give me one more chunk of data to with all the other data to give me every inch of horsepower.

95bowtie

That is exactly how mine looks too. Same with the inside of the pipes, looks like they have never been ran before clean as **** still.

CALL911

iTrader: (17)

^ This

Tuning on boost is such a delicate process that is more detrimental than N/A tuning it would seem foolish to tune purely on EGT's.

Can you determine knock from EGT's? What about running lean? It should be hotter when lean, but how much? What are you planning on using for your "safe" EGT? This would also be a big concern if this is what you were looking at to tune with. If you were shooting for some specific EGT to tune for, I doubt the rest of the tune would be nearly as accurate as using other normal means.

gnx7

iTrader: (28)

I know WB02 tuning is where it's at...... was just curious why nobody looks at EGT #'s as well. I'm running the Holley EFI so that answers that

The Buick GN stuff was crazy primitive. My chip back in the day was so far off the charts and running rich..... only when the DA dropped and temps were super low did it really run good. I dynoed it once.... and above 4,000rpm the power just fell off as it was simply running too rich. Still ran mid 11's on a stock GN turbo/engine with small cam in a 2800lbs RX-7 first time out.

The Alchemist

iTrader: (19)

The reason is the expense to get the setup, then, what do you do with the data once you get it?

With a factory pcm, which 90-95% of the people in this section are still using, you can't control individual cylinder injection. So seeing the individual cylinders temperatures just opens pandoras box. I agree, if you're going for a max effort setup, where you can customize the intake manfiold runners, and adjust the tune of each cylinder, then it's worth it. But for most of us here, it doesn't make sense.

Forcefed86

iTrader: (4)

My racing roots started in the primitive Turbo Buick world as well. Squeaked out a 10.06 in 3.8 powered RX7 before jumping into the LSX turbo stuff. I'd see 1600ish on kill at the track. This was an OEM iron headed 3.8 with meth inj. and pump fuel. I'd see high 1400's/low 1500's when I switched to E85. Never really looked at it much after I made the E85 switch.

I think the same rules apply. All setups will be slightly different because of EGT placement and slight variances in the combinations. TB guys told me I'd have to run the motor to failure while logging, then record the EGT temp the motor failed at to get a proper "do not exceed" point I was asking for.

We always used the plugs to try and determine the leanest cylinder. Then ran the thermocouple in that cylinder runner as close to the head as possible in an attempt to get the hottest cylinders readings.

soundengineer

iTrader: (16)

Actually...
EGT is extremely useful....especially when used in conjunction with a wideband.

Hottest temps will be at Stoic.
From there it goes colder either direction lean or rich.

There is no set value you can shoot for...
It is a per vehicle thing.
It will vary every setup...
Somebody telling you to shoot for a specific egt is telling you wrong.


Its useful in balancing fueling cylinder to cylinder... and you can see misfires and knock with an egt probe.

The key is exacting placement.. about 1" from the exhaust port
And placed at the proper depth as well.

87silverbullet

iTrader: (11)

Who told you that? Or did yo come up with that bull all by yourself?

soundengineer

iTrader: (16)

That is how it works...
Your hottest burn is always Stoic.

soundengineer

iTrader: (16)

Here's a few pictures that might help you understand as well...

soundengineer

iTrader: (16)

Not to mention my own personal experience on my car and several other cars I've done tuning on as well...

87silverbullet

iTrader: (11)

So you pull 2 graphs and one is from a motor scooter website and the other is about balancing cylinders at rpm between idle and 2100 rpm's?

Man, were talking about WOT here on a performance engine not a scooter.

My turbo buick ran an EGT of 1550 with no issues but when I was in a grudge race I ran the motor super lean and the EGT shot up and melted the pistons like someone poured acid on them. So you mean to tell me I was headed to stoich when my EGT's went up?

soundengineer

iTrader: (16)

I pulled those pictures because they are correct...doesnt matter what site they cam from
the point was to show 2 different graphs to show it wasnt just a made up value...
you do a search for EGT and 1000 graphs show up all looking exactly the same as what I posted


I've been doing EGT's for years
still need to add it to the new foxbody project..but I have other priorities on the car right now...and I have a while till i need to add it...still not ready to go down the track in this one yet

EGT applies the same at part throttle or WOT...
if you melted pistons.. you had a heat build up...
EGT at WOT will be higher than at part throttle..
part throtle EGT's will be a couple hundred degrees less that at WOT

so 12.5 AFR will be cooler at part throttle than at WOT
14.7 will be cooler at part throttle than WOT
15.8 will be cooler at Part throttle than WOT



knock will also drive the EGT upwards
(this is why you still need a wideband...because if WOT AFR is good, but heat goes up suddenly and unexpected...you had some knock)

I dont know why you melted pistons in your old setup..
you either went lean...and stoic would be lean at WOT...
or you had a bunch of knock (or a combo of both)



but if you and started going towards stoic, you would make more heat

once you pass stoic, the heat starts going back down because you have less fuel to burn..no fuel, no heat

you say you ran around a heat range of 1550...but what was that in reference to?
were you reading plugs? did you use a wideband?
and at the end... what did you determine was the cause of your melted pistons? they dont just melt for no reason


what confuses people is when they go lean, and they have knock...the heat continues to rise...even when you pass stoic...
so if you start at 12.2 afr...and go lean...and you get to 14.7....and still arent knocking, then EGT will go back down after that(not exactly at 14.7.. theres a little spot within a few points that it stays basically the same..a little flat spot in the curve)...as long as you dont have knock... the leaner you go, the cooler its going to get...
but...if you start to have knock, it will drive the temperature back up again...even on the lean side of 14.7.

87silverbullet

iTrader: (11)

.......Cant dazzle them with brilliance.......baffle them with bullshit............