Originally Posted by Braineack
(Post 1482090)
really? it's almost 10° retarded below stock timing at 100kPa, and the same in boost... thing is hitting single digit spark angle at 7psi?! i'd be running 20° there...
|
Originally Posted by Tran
(Post 1482061)
Do you suggest just letting the fuel enrichment at high IATs solve that?
Off topic, but I've just seen you're in Tampa. I'm heading to Orlando tomorrow for 2 weeks, is there any Miata related stuff happening round there in the next two weeks? Miata events? Some of the local Tampabaymiatas forum guys meet up every week. Check that forum for details.
Originally Posted by Braineack
(Post 1482090)
really? it's almost 10° retarded below stock timing at 100kPa, and the same in boost... thing is hitting single digit spark angle at 7psi?! i'd be running 20° there...
I didn't get to see his spark map because I'm still using the mobile app. |
Originally Posted by sixshooter
(Post 1482140)
If tuned properly the EGTs will be fine.
Miata events? Some of the local Tampabaymiatas forum guys meet up every week. Check that forum for details. Highly retarded spark causes skyrocketing EGTs. I didn't get to see his spark map because I'm still using the mobile app. Is the consensus here that my spark is so retarded that my EGTs have gone mad? |
High EGTs are often caused by retarded spark and Brain says your spark is very retarded... ergo...
I'm not doing any events right now because my car is apart for upgrades. Chin is doing a track weekend at Sebring this weekend. http://chintrackdays.com/subevent.aspx?q=xVL48cM4P6w%3d NASA and PDG aren't running locally in the next two weeks. Hooked on Driving will be at Palm Beach International Raceway on the 27th. HOD PBIR Cars and Coffee is too dangerous. lol. There's a huge classic car cruise-in at Old Town in Kissimmee on Hwy 192 on Saturday afternoon and evening unless it's raining. |
1 Attachment(s)
Originally Posted by sixshooter
(Post 1482213)
High EGTs are often caused by retarded spark and Brain says your spark is very retarded... ergo...
I'm not doing any events right now because my car is apart for upgrades. Chin is doing a track weekend at Sebring this weekend. Sebring 05/19/2018 - 05/19/2018 Chin Track Days NASA and PDG aren't running locally in the next two weeks. Hooked on Driving will be at Palm Beach International Raceway on the 27th. HOD PBIR Cars and Coffee is too dangerous. lol. There's a huge classic car cruise-in at Old Town in Kissimmee on Hwy 192 on Saturday afternoon and evening unless it's raining. I'm tempted to go to Sebring this weekend. Do you know what the Chin events are like to just pop down and spectate? I assume trying to blag a passenger ride is totally out of the question. I'll give the Old Town cruise a look too, though maybe next weekend. Back on topic, is there a recommended base spark map to try? If mine is that far off, it probably doesn't make much sense to continue with it. Thanks, Tim |
An update to this to whom may be interested.
I had checked base timing, but I hadn't checked it with RPM. I did this and it revealed that the timing was retarding with rising RPM. It wasn't a huge amount, but needed 75us on the MS3 before it held steady. By my calculations, this is worth ~3 deg of retard at high revs. Also, I took the car to be mapped for the better fuel I'm going to run in it (99 RON, looks roughly comparable to US 93). Even with keeping a decent knock margin and doing painful 25 second det checking pulls, it was possible to reach MBT up to 16psi, which is where the tuner stopped since EGTs were hitting 900C in a 25 second pull. This needed an extra 4-5 degrees even with the latency correction. I'm not quite sure what the limit of the OE VVT valves are, but don't really want to find out the hard way. I wish I had inconel exhaust valves, but the car feels plenty quick as is. (I'll see how I feel about this when my friend finishes his forged build with inconel valves...) I ran a full trackday yesterday at Brands Hatch Indy and EGTs were fine all day, though admittedly conditions were bad, so I was on low boost (10psi). We'll see how it fares at Silverstone later in the month.... |
Do you have the settings enabled that pull timing with MAT? I had that and it killed two turbos on the track because of high egts.
|
Originally Posted by sixshooter
(Post 1510965)
Do you have the settings enabled that pull timing with MAT? I had that and it killed two turbos on the track because of high egts.
Which turbo did you melt and do you have an estimate of what your EGTs were when it happened? What exhaust valves were you running at the time and did they survive? |
They were Chinese 2870s. Method of failure was cooked bearings and hotside seals. Flapper rod for IWG started sticking, too. It stopped being a rod and began acting like a noodle above a certain point. I also had multiple fastener and downpipe failures.
I'll advise you to raise your threshold for MAT timing intervention and only remove timing fractionally when it becomes active. 140*F is not unusual for a factory turbo car driven hard on the track and superchargers can get higher. Pulling timing will make the entire engine run even hotter and will often overheat the cooling system. I'm still running the same head and factory valves. I'm using the Supertech double springs. About 320whp according to virtual dyno, so 350 European horsepower, haha. Running excessively rich can cause high EGTs because of the unburned or still burning fuel entering the exhaust. This can be exacerbated by a late spark. |
Originally Posted by sixshooter
(Post 1511037)
They were Chinese 2870s. Method of failure was cooked bearings and hotside seals. Flapper rod for IWG started sticking, too. It stopped being a rod and began acting like a noodle above a certain point. I also had multiple fastener and downpipe failures.
I'll advise you to raise your threshold for MAT timing intervention and only remove timing fractionally when it becomes active. 140*F is not unusual for a factory turbo car driven hard on the track and superchargers can get higher. Pulling timing will make the entire engine run even hotter and will often overheat the cooling system. I'm still running the same head and factory valves. I'm using the Supertech double springs. About 320whp according to virtual dyno, so 350 European horsepower, haha. Running excessively rich can cause high EGTs because of the unburned or still burning fuel entering the exhaust. This can be exacerbated by a late spark. How do you recommend to avoid knock at say 140F MATs if there is minimal spark retard there? Do these engines not really need much MAT retard? |
You don't need much MAT retard. I'm using pump gas on the track in hot weather in Florida. I'll look up the values I'm using when I get to my laptop if you want to see them.
Cold air is more dense than warm air so some tunes actually detonate more in cold weather. Cold MATs create a lot more cylinder pressure (and power). |
Originally Posted by sixshooter
(Post 1511254)
You don't need much MAT retard. I'm using pump gas on the track in hot weather in Florida. I'll look up the values I'm using when I get to my laptop if you want to see them.
Cold air is more dense than warm air so some tunes actually detonate more in cold weather. Cold MATs create a lot more cylinder pressure (and power). |
It pulls 0.5 degrees at 170 degrees and 1 degree at 190.
|
Thank you!
|
All times are GMT -4. The time now is 05:08 AM. |
© 2024 MH Sub I, LLC dba Internet Brands