Stroker timing and EGTs

[turboAWDfanatic]

I have been trying to come up with a good tune for a while now with my 2.3L without much success. I'm running stock cams and a Evo III 16G GT turbo w/ a Punishment FMIC (I know, I'll get a bigger turbo when I can).

From the reading that I've done, the 2.3L motors w/ higher compression (mine is 8.8:1) like more conservative timing. I modified my EPROM with 2G timing maps, and reduced the timing even more form there. Basically on my highest load map I'm running 10 degrees of timing and 11.0:1 AFR.

The question I have is whether or not I should be worried about high EGTs when running such conservative timing. NOTE: I am *not* tuning off EGT...I have a WBO2 and I can monitor knock via my stock boost gauge converted to a knock gauge. Well, when running 10 degrees of timing I get EGTs in excess of 940 degrees celsius even when I have zero knock and 11.0:1 AFR. I realize that this high EGT is from later combustion an not necessarily b/c of extreme temps inside the cylinder.

Should I just plain ignore EGTs when I have timing control and the ability to monitor knock and AFR? (Again, just to reinforce, I'm not tuning off EGTs, just noticing they are extremely high b/c of the late timing I am running). How late is too late when it comes to timing...ie at what point am I just wasting the combustion cycle by shooting flames out the exhaust valves? How hot is too hot...can I end up doing damage to my turbo w/ sustained temps exceeding 950 degrees in the higher RPM range during WOT?

TIA for the help!

 

[2point3Tsi]

I would like to know what is "normal" for stoker timing I'm close to your setup except I have cams and a t25(don't tell me I know its small, the BW S258 is going on soon enough)

 

[viperlp01]

Ya that is hot ...1742 degrees F is about 150 degrees hotter than safe i would say... Way too hot.. Remember here... If the timing is not advanced enough you are shooting still expanding exhaust gases through the head into the turbo. Not only that but retarding makes stuff alot hotter than advancing.. I would try more timing... What boost levels are you pushing with that 16g??

 

[turboAWDfanatic]

I can run about 23-24psi on a cool day without knock, but *with* high egts. Mind you, this is on crappy CA 91 octane pisswater. I've backed the boost down a bit to 20psi. The problem is, while I'm enjoying the benefits of low end torque and quick spool from the stroker, overall I'm not putting down much power.

I've been referring to this thread for info on what timing to run. The portion of that thread that caught my attention the most was the following:

Most of us run our strokers at lower timing. The amount of heat the turbo generates will have a direct affect on combustion temps so this changes the equation as well. My setup runs 8 degrees on pump, Jake Hanhardt (topstreet) runs between 10-13 on his and Dan Kasun (project_tsi) runs 12 on his with no meth although I'm sure he'll add more timing with the methanol running. When I told the guys at Buschur I was running 12, their exact words were "wow, that's a lot of timing on a stroker."

How do they run 8-10 degrees of timing and higher boost w/o EGTs going through the roof? Is the real answer to all of this simply "get a bigger turbo" so I can flow more at lower PSI and keep things cooler, or can I get more out of my 16g with better tuning? I can't keep up w/ other DSMs running 20g and 50 trim turbos on their bone stock motors tuning w/ AFC or even guys that are running 16g turbos on stock motors with 'link. Pretty sad considering all the money I've sunk into a fully built stroker.

All that being said, I'm in heaven when I'm at AutoX. 20psi by 3,000rpm FTW!!!

 

[turboAWDfanatic]

Any other thoughts? Those of you running lower timing on strokers, what turbos are you running and what EGTs do you see?

 

[HIGHPSI4]

I had a 2.3l 8.8 to 1 ratio engine for a while. I did have the timing bumped down but ran a GT35R. I did not have any egt problems. Now that most people are running WB no one is even installing the egt gauges anymore.

 

[bastard dsm]

im running as low a 8deg on our 2.3 galant at 24psi on 93 with a s366. it can range from 8-10deg of timing, but also remenber the stock evo timing map runs 10deg of timing also.

 

[turboAWDfanatic]

Do you log EGT by any chance? How high do you rev that engine? Whenever I retard the timing to anything less than 11-12 degrees, the EGTs go way above 900 degrees Celsius. I still get varied opinions as to whether or not this is harmful to the engine or the turbo. Is a bigger turbo with a cooler air flow the answer, or am I doing something wrong with the tuning?

 

[bastard dsm]

i would also ask the same q about egt's when i had a guage, but i dont use it any more or even worry about it.if its not throwing knock counts then dont worry about it.

 

[turboAWDfanatic]

Just want to add a little info here since I've been learning more while tuning my car. In asking around, the consensus seems to be that *yes*, excessive EGTs can be damaging, but not in short spurts. Sustained high EGTs are bad. BUT, I've gotten past the EGT problem with my timing. I was lowering the overall timing and flattening it out too much through the RPM range, so as RPM would go up, I wasn't adding enough timing which was causing the high EGTs. The trick (for people running strokers and high compression, especially w/ a small turbo like me) is to lower your timing around peak torque, but then bring it back up with RPM. Right now I'm running about 7 degrees of timing on the top load level from 3,000rpm to about 5,000rpm, but then I start bringing it back up and end up at about 12-13 degrees by redline. With this timing, I have been able to run 23lbs of boost safely and still keep EGTs at bay in the higher RPMs. One thing I should mention, though, is that since my 16g is internally gated, I have poor boost control and it drops off as the RPMs go up. I end up w/ about 17-18lbs of boost at red line. So, if I were to hold the 23lbs to redline, I'm not sure how the engine would react as I bring the timing back up. I kind of want to put on an external gate so I can hold boost, but I don't want to have to dial it down to 18-20lbs just to keep knock at bay at the higher RPMs.

 

[Rob10_99]

Good thinking with the timing advance past the curve. From what I remember 850C is about the limit when it comes to EGT's, and that is high. Which is roughly 1560F, about the limits for aluminum.
Prolonged temps will melt pistons/warp heads/burn valves etc.

 

[thecman02]

Ohhh your holding boost problem is most likely due to the turbo not being able to keep up with feeding 2.3l's of beast haha.

 

[turboAWDfanatic]

, actually i believe it's mostly due to the large flapper that came w/ the Evo III GT turbos, but yeah, 2.3L tends to dwarf the 16g. Hopefully getting a Holset soon (heh, been saying that for about a year now)