EGT temps with alky

[turboadict]

Just got an EGT installed with the temp probe in the origional O2 sensor hole.

What temps do I need to be aiming for at the track?

Would the EGT numbers to shoot for with the alky be the same as without alky?

I'm running Iso and water 60/40 unless I can find out where to get some Methanol from.

My annual pillgrimage to the track for a 3 day event is soon and I'm hoping to crack the 11's this time around.

[BLACK6PACK]

I always ran denatured from home depot. The water can change the 02 readings from a standard strait alky setup. My car was fastest in the 1600-1650 range. That's starting to get warm, under 1550 it was a dog.

[FatGnat]

Black6pack....were those temps pre or post turbo?

[Sweet6]

I ran mine at 1700 pre turbo. No knock.

[DonWG]

Just for reference guys, at the mixture strength I'm presently running, my egt is 1200 F.

[Razor]

Preturbo 1500-1650 depending on timing. Higher timing has less EGT.

[turboadict]

I'm looking at pre turbo, running TT chips.

street chip 20/18 degrees timing around 18# no knock.

Strip - alky chip, 23/21 degrees 25# boost.

Seems like I can expect a difference between them EGT wise. Is this more to do with the timing difference or the alky being sprayed in there?

Any numbers to aim for for each set up to get me on the right track would be a great help, tuning with the EGT is new to me and I wasn't sure what to aim for.
Always tuned to stock O2 sensor readings prior to this. Car seemed to like it lean, around 730-750 at the top end of third with alky (iso/water mix about 60/40).

[Razor]

alky is not iso mixed with water.

See now you introduce water into the equation. And then introduce ISO into the equation as well. As it is a different form of alcohol.

Around here, when someone mentions alky.. 99.9% of the time its methanol and straight methanol being used.

With ISO and water.. your getting your own data and figuring your stuff out. As few here follow that path.

[turboadict]

I didn't mean alky was iso/water, just quicker to type alky. Didn't mean to confuse the post.

With the O2 numbers senario, I never found a difference with numbers when I injected the iso/water mix and tuned for best mph. Maybe the isopropynol offsets the extra oxygen added with the water? Don't know.

Anyhow, just wondered if I should be shooting for different numbers as regards to EGT with or without injecting it, and as I've learnt here, with higher timing.

Assumed (probably wrongly) that the exhaust gasses would be at a certain temp at a certain air/fuel ratio. An optimum air/fuel ratio would give you X degrees EGT. Sound like there are many variables at work here. Might have guessed it wouldn't be that easy damn it.

Didn't know the best numbers to start from and any information I can get from you guys through experience is a great help. Don't get to the track often out here in the UK. Just need pointing in the right direction.

[BLACK6PACK]

Originally Posted by FatGnat

Black6pack....were those temps pre or post turbo?

pre turbo

[turboadict]

Alrighty, managed to get a hold of straight methanol, so that's what I'm going to run this weekend.

I'll be using a TT alky chip with 23/21 degrees timing at @25# boost.

What EGT should I be shooting for here? As I said before this is my yearly blast at the track and tuning time is short. Any help appreciated.

[pacecarta]

looks like you're try to circumvent the tuning process and go straight to headgasket replacemnt by basing your tune direction solely on EGT temps
tuning is not something you should be rushing especially when pushing the limits

with 30#s and a TA49 i'd be worried that any performance gains made from your current 12.23/109 . without close and patient monitoring could lead to a bad day at the races. the 49 with alky tuned can easily get you to mid 11s (depending on your 60') at 115+ , after 12.30 your addition of meth is the only thing carrying you to the end of the track , the leaner you get with fuel the higher the EGT(to a point then it goes the other way) and the more alky you need the lower the temps will be
generally look for mph gains then when your tuning produces no more gains then look at your egts , thats what your car will like
that said 1575 has been working for me , it does get faster around 1600-1650 but your playing on the edge and you really need to be careful and monitor(log) the tune

[turboadict]

I've just swapped the injectors for 36# blue tops that a freind of mine had. Was hoping to pick up a set of 60# motrons at the GS nats but vendors seemed a bit thin on the ground and I couldn't get hold of any.

Met Eric from TT and he burnt a few chips for the 36's for me, so I'm hoping I can tune with these and scrape an 11 second pass.

Just installed the EGT gauge so this is a new one for me. Always gone by the O2's before. Hoping for a more accurate baseline tune to aim for. Seems like there is much more to it that I thought, what with temps changing with timing, amount of alky etc.

Hopefully, come monday I can post a new personal best.

[pacecarta]

you say your egt probe is in the OE o2 hole , where did the O2 sensor go?

[turboadict]

O2 sensor is now just after the turbo in a TH type 3" D/pipe. Stock type narrow band.

[pacecarta]

im setup like yours ,

tuning on O2s from a narrowband are a bad way to do it
im running the 02 after turbo but only use for driveability , the o2 placed after turbo really should be heated as it mmay not get up to temp for accurate readings at idle
what i also found was that with the o2s after the turbo (denso BTW) the o2 #s were much higher than pre turbo at WOT under higher boost because youve gotten the sensor away from pressure (and a few 100* egt ) which can cause the narrow band sensor to take a dive making you belive the tune is going lean
prior to moving i would see 720s to 750s at top of track (some low 700s but at about 11.5 A/F) , now same sensor moved after turbo is showing 845-860 through entire run
oh and incase you're going to say that tune must have changed
AF is kept stable at 11.2-11.3 , running WB correcting with an LC-1 WB sensor down at far end of down pipe and egts from run to run are usually so close you'd think i forgot to reset the egt memory .
i log egt every pass and besides looking to be sure im not doing damage from excessive EGT i basically use it as a quick check after a pass so i can be assured the tune stayed where i wanted , if egt did vary i would look much deeper into my log of the run before making another pass.

[turboadict]

Hmmmmm, now this is getting interesting.

My O2's used to be like yours before I moved the sensor - 730-760 or so is where it liked it best. O2 was heated, I now have the Denso. I haven't tuned the car seriously yet, just some wot runs to the top of 3rd gear and logged the data with turbolink, just to see where I was at.

I noticed that the O2's were indeed higher after moving it (around the 830 mark but very stable) but assumed that this was the TT chip fueling with the 36# inj. Lowered the fuel pressure some, O2's down to 780's. No knock but the car seemed to lay down a bit. No wonder, this was probably way lean.

Seems like the best thing to do would be get the O2's back up into the 830-850 range and start the tuning process agin, see what the car likes, find the mph, then use the EGT temps from this for my own reference.

I origionally had the impression that EGT would be a faster and more accurate way to tune the car. After 11 years with the GN you would have thought I would have learnt. Lots of variables whichever way you tune it when you are swapping chips from street to strip with timing changes and adding alky etc, etc.

I always ran the green stripes and thrashers and over time knew where I was at and what to shoot for. Now with the changes it might be wise to start the process again.

Thanks for your input, I didn't know about the O2 readings being that far off by moving the sensor. Probably saved me an awful lot of greif - or just a slow timeslip if I was lucky.

What are your EGT's by the way?

[GNVYUS 1]

Curious what the whole EGT setup cost vs $300 on a wideband and just got the answers you needed right away?

[turboadict]

haven't been able to play with the car much for the last few years because of various things and just getting back into it again.

Picked up the EGT for about $170 from RJC. Last time I looked at wide band stuff (it was a while back I will admit) they were stupidly expensive and it really didn't seem long ago that people were swearing by tuning the cars with EGT.

Things move on I guess and I got left behind a little bit.

Still a bit supprised no one came back with EGT numbers, must be a whole bigger can of worms that I thought.

Fitted some different injectors to move on a bit, Eric burnt some chips for me and I got the EGT gauge - hoped to get a better handle on this than by using the stock O2 sensor alone. And now seeing as I moved that it seems the numbers I'm looking for will be different.

I wish I'd left it all alone and not bothered.

I basicly just hit the track over a three day weekend once a year and try to get a little faster each time.

[turboadict]

As a reply back to pacecarta, As I have learned, the O2's are now different at wot. Will the diferent placement of the O2 sensor skew the whole setup for the ecm and mess with the running of the car? Obviously the ecm is still looking for it's usual numbers for closed loop.

I hope this wasn't a bad move.