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TR6 Lambda sensor location


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Probably a question for one of the EFI boys.

I have an old Innovate Lambda set up and AFI gauge left over from a previous project lying around gathering dust so I thought I might put it to work in helping set my car up when the time eventually comes. Once set up the gauge will be removed and used only if/when required.

The car will be std with a duel down pipes from the OEM cast manifold so I was wondering where's the best place to weld the bung into the exhaust? 

Thanks

Andy

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I went efi last autumn (emerald) with heritage throttle bodies plus wasted spark. Final set-up was on rolling road at emerald. At conversion time I was told a lambda was not needed and I've done about 1k happy miles since. I'm now wondering if I've missed something though, so can someone explain please what extra a lambda would achieve on my setup? No point me spending money I don't need to, but I am curious. 

Cheers, Mike. 

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Unless you have a loopback feed for lambda to continuosly monitor mixture, you don't need it. Mine is only used for initial setup. I think Emerald sample the gases at the exhaust pipe outlet when they do the initial setup on the rollers, but I don't have Emerald so stand to be corrected.

Jerry

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1 hour ago, jerrytr5 said:

Two Ed, now that's just boasting.

Jerry

Well, now you've embarrassed me, Jerry!

There was some rationale, though.  Even though there are cross-connections on both induction and exhaust sides, most of the gas in one exhaust pipe comes from the three cylinders fed by one of the carbs, especialy at higher RPMs.  This can help identify a mixture problem in one of the carbs.

In theory, anyway.

Ed

 

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I installed my single sensor just a bit lower than Ed’s sensors. Trial fit the sensor before drilling and welding.

It should not collect condensed exhaust gasses, so make sure it is self-draining. 

It also requires a permanent feed to warm the sensor. I fitted an auxiliary fuse box for that, switched by a relay from the ign. switch. Mine juste “reads”, and shows AFR. Interesting to see the behaviour, during cold start, at idle, when accelerating etc.

Waldi

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Thanks all.

Seems its best as high upstream as possible to get it to working temperature faster.

A pity it won't go into the cast manifold might have to be as exuberant as Ed and fit two as its a dual exhaust system. 

Andy

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Hello Andy

                    They do not want to be to high upstream as they can get to hot and they also do not want to be below horizontal or can suffer from moisture etc

There is plenty of information on TinterWeb about positions

1 hour ago, Waldi said:

It also requires a permanent feed to warm the sensor

My Microsquirt controls it and turns it off if the engine is not running after a few seconds as I believe they can be damaged by being left on but also they are damaged if not on when the engine is running I believe?

Roger

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2 hours ago, PodOne said:

Thanks all.

Seems its best as high upstream as possible to get it to working temperature faster.

A pity it won't go into the cast manifold might have to be as exuberant as Ed and fit two as its a dual exhaust system. 

Andy

Have a look at this link for an install into a cast iron manifold.

http://www.74tr6.com/exhaustmanifold.htm

 

Simon

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Unless you're incorporating the Lambda sensor into a feedback loop, the distance from the manifold isn't a big deal. If it has its own heating, even less so. I originally had one fitted just before the silencer, and moved it to the downpipes when I had a new exhaust system fitted. The relationship between manifold vacuum and AFR didn't change, even when looking at narrow RPM bands. Not that I could see, anyway. Obviously, if you're using the sensor to drive an EFI it's different. But for tuning the Lucas PI, or carbs, fit it where convenient. In fact, probably best at a point where the mixture from the two downpipes is fully mixed. Unless you can boast two sensors!

Cheers,
JC

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On 6/1/2021 at 3:29 PM, Mikell said:

I went efi last autumn (emerald) with heritage throttle bodies plus wasted spark. Final set-up was on rolling road at emerald. At conversion time I was told a lambda was not needed and I've done about 1k happy miles since. I'm now wondering if I've missed something though, so can someone explain please what extra a lambda would achieve on my setup? No point me spending money I don't need to, but I am curious. 

Cheers, Mike. 

Don't need one for running open loop but setup, tuning,  data logging etc is invaluable. You sure they didn't fit one for tuning and then remove it and fit a blanking plug? Or maybe used their own downpipes for tuning?

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To be honest I don't know the detail of how it was done.....following the installation & initial set-up the 5 was simply trailored to Emerald for the final rolling set-up. Since then it has been driving a dream, so I'm more curious than concerned but I'll ask the questions as a "nice to know" though. 

Cheers, 

Mike. 

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  • 2 weeks later...
6 hours ago, Lebro said:

Is this of any interest ?  found while looking for something else !

https://www.ebay.co.uk/itm/203482286157?hash=item2f607d484d%3Ag%3AepQAAOSwvYFgpqQF&LH_Auction=1&LH_ItemCondition=4

Bob.

Thanks Bob on my watch list:D

Andy

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