EGT cylinder tuning / header mods

[Nadine UK GTS]

I have read many tech articles of air/fuel ratio versus EGT (exhaust gas temperature) readings, basically concluded air/fuel is best to tune by, but for individual cylinder tuning and keeping an eye on each cylinders temp (motor safety, which is priceless) decent EGTs are great. I searched and found EGT sensors were expensive, there were no kits to cater for 10 cylinders, so I've lived with installing a wideband air-fuel per bank, but always been interested with individual EGT outputs. Sean Roes VEC2 has the ability to trim or add fuel per cylinder, coming to a rest somewhere, pulling and reading the plugs is good to 'see' what's going on per cylinder combustion, but I wandered what my Beloveds 10 chambered heart was pumping under different conditions. There's no way on a power run you could watch gauges for this, but I found SPA (digital gauge UK company) had a duel gauge that had recall facilities...after talks they were interested in helping me out in my quest.

When I was out in USA recently, I was lucky enough to get taken up in a light aircraft, and then after asking many tech questions, handed the controls to fly it!! As we gained altitude we leaned the motor out, according to the EGT reading, very interesting. So performance and flight inspired, I had some lugs machined with 1/8 BSP thread to take EGT thermocouple probes! Here's the lugs welded on my headers (the headers I had ceramic coated, hense white!)

One of the sensorsenders in place

The headers on the motor

Plane EGT and many gauges!

The plane I was handed the controls to, never flown anything before!

While my headers were off I got these crude 'pickles' cut out:

There's thought on a forced induction motor the pickles could hurt power, so out they came!

 

[KenH]

That's pretty cool! I have tried to take individual header tube readings with an external thermocouple, but it is difficult to get repeatable readings and obviously limited to idle type conditions. Please share the data when you get it as it would be interesting to see.

I would also be curious if you notice any difference on HP with the pickles removed from your headers as well. Any chance of a before / after dyno number?

 

[BlueGTS]

I had an EGT gauge in my previous car and eventually moved to a wide band 02 gauge which I know you already have. I understand what you are trying to do and getting a reading in each tube is a great idea. However, I will give you my opinion on EGT gauges.

As you know the EGT gauge is alerting you of a lean condition by registering a greater temperature. The problem I found is what temperature is too high? What does that temperature reading equate to in Air/Fuel ratio? For example, if the temp rose 50 degrees what does that mean? I was unable to tune at all with EGT and just ended up using it as a warning devise. The temperatures registered on the gauge are only useful if you have reference points with which to compare them too. Without reference points from your own car the temperature readings are not all that useful.

What you will probably end up doing is taking note of any cylinder that is registering a higher temp than the other 9. You would then add fuel to that cylinder to get the temps in line.

 

[SilverSnake]

I have used egt's for years on my dragster. If you go over 1350 degress on a n/a engine you are getting lean. I ran my 565 ci Big block chevy at 1325 degress as a norm, But altitude and any weather changes can make a huge difference.
I have not ran a egt data logger system on a fuel injected engine yet.


Robert

 

[Nadine UK GTS]

Ken, Aaron, Robert, thank you for your replys.

Sadley no chance of dyno #'s, there's no dynos local to me that can take the 700+ But getting the pickels out on a forced induction motor I think has to help.

The sensors may well just serve as a warning and point of interest, that's what I was hoping for. Thanks for actual temp reading values, very valued. Also interesting reply on Alley site post re the temp readings!

 

[Jack B]

Nadine:

Check out Innovate, they just came out with an affordable logger for multiple EGT's, in general their logging firmware/software is exceptional.

 

[Mr Hemi Head]

Welded headers supported by the sofa. Nadine you certainly have your priorities in the right order.LOL
Rick

 

[Nadine UK GTS]

Thanks Jack for the info re that, sounds just what I need. The VCA and Alley forum replies have been fab, you have all been so much help, I had been searching the internet and reading up, but you've all told me the real stuff I need to know, that net searches didn't throw up. Thanks.

Hey Rick, I have no use for that sofa, if I lost it I wouldn't be sad (my dog would miss it though!)

 

[pedro]

Did you gain any HP by cutting out exhaust pickles.Im runnig a roe supcharger with a 10 psi looking to gain more power.I was looking to cut them out to if i gain some more hp.Thanks

 

[Nadine UK GTS]

I don't know if and how much the pickles removal may gain, I'd like to know too! I'm thinking it will help! I'm not able to get on a dyno; I'm still working on my car, so stuck in the garage on axel stands (as I've had other problems). With wet UK climate, we're lucky sometimes to get the chance of track time in May.