Another Engine Dynoed today.
10-02-2014, 03:19 PM
#32
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EGTS were 11s and low 12s. People misunderstand boost , horsepower, fuel octane etc... mostly has to do with the air intake temps and a/f ratio.....mine at 20% overdrive never exceeded 114 degrees....i believe the rule of thumb is to below 200 degrees on the hottest day. EGT's mainly also deal with detonation from timing...alot of times when retarding timing you will see egts creep up and get hotter... Mike tkach or mild thunder step in and correct me if I'm wrong on any of this...
10-02-2014, 03:44 PM
#34
EGTS were 11s and low 12s. People misunderstand boost , horsepower, fuel octane etc... mostly has to do with the air intake temps and a/f ratio.....mine at 20% overdrive never exceeded 114 degrees....i believe the rule of thumb is to below 200 degrees on the hottest day. EGT's mainly also deal with detonation from timing...alot of times when retarding timing you will see egts creep up and get hotter... Mike tkach or mild thunder step in and correct me if I'm wrong on any of this...
A heavy vee bottom may run into detonation at peak torque rpm, faster than a light cat at peak torque rpm.
10-02-2014, 07:58 PM
#35
Even the quench design of the piston plays a part in timing. Better piston design, less timing will be required as a more homologous mixture will give you a faster more efficient burn.
In some of the turbo 4 cylinders we used to race we ran lower timing on our motors and trapped faster than others. We weren't stuffing in run of the mill Wiseco pistons though, we were running a custom slug with a quench pad on the top to distribute better. It worked, and we also had far less knock issues than others, running boost in the high 30's to lower 40's.
In some of the turbo 4 cylinders we used to race we ran lower timing on our motors and trapped faster than others. We weren't stuffing in run of the mill Wiseco pistons though, we were running a custom slug with a quench pad on the top to distribute better. It worked, and we also had far less knock issues than others, running boost in the high 30's to lower 40's.
10-03-2014, 09:20 AM
#36
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Hey Andy. I've been running 34 degrees in my blower engines for a long time with good results. Actually for a while, they were at 35* total. Mercury, ran 35* in the 525sc, and 33* in the 600sc. No intercoolers and iron heads. Granted the boost was less, but the air charge was much hotter in those.
I think what scared guys away from ignition lead, was the fact 20 years ago, guys were tuning their engines by glancing at a spark plug once and while. When the engine would get hurt, they'd blame timing, and retard it. Not realizing their fuel tune was way off, their cam choice was way off, and other issues. So they retarded the timing to help crutch the engine, from hurting itself again.
The chamber design, camshaft design, crankshaft stroke, air intake temperature, coolant temperature, quench factor, engine rpm, will all play a role in what an engine will like, or tolerate, as far as ignition lead. The days of retarding the timing to 28* in a big block to keep it together should be long gone.
I have no issue with 34 or even 35* at 6000 RPM. However, I would be all for, running a programmable ignition, such as the Daytona Sensor box, where it allows you to pull timing around around Peak Torque range, but still have lots of lead at idle and WOT. IMO, that is where you'll get into trouble with too much lead. You prob wont hurt it holding it at 6300RPM wide open for a poker run, but you may hurt it cruising along at 4500RPM with a boat full of people on a leisurly ride, if in fact, you have excessive lead.
As far as the EGT temps, hottest I saw on this yesterday was about 1320 on the #5 cylinder. Most were in the mid to upper 1200's.
I think what scared guys away from ignition lead, was the fact 20 years ago, guys were tuning their engines by glancing at a spark plug once and while. When the engine would get hurt, they'd blame timing, and retard it. Not realizing their fuel tune was way off, their cam choice was way off, and other issues. So they retarded the timing to help crutch the engine, from hurting itself again.
The chamber design, camshaft design, crankshaft stroke, air intake temperature, coolant temperature, quench factor, engine rpm, will all play a role in what an engine will like, or tolerate, as far as ignition lead. The days of retarding the timing to 28* in a big block to keep it together should be long gone.
I have no issue with 34 or even 35* at 6000 RPM. However, I would be all for, running a programmable ignition, such as the Daytona Sensor box, where it allows you to pull timing around around Peak Torque range, but still have lots of lead at idle and WOT. IMO, that is where you'll get into trouble with too much lead. You prob wont hurt it holding it at 6300RPM wide open for a poker run, but you may hurt it cruising along at 4500RPM with a boat full of people on a leisurly ride, if in fact, you have excessive lead.
As far as the EGT temps, hottest I saw on this yesterday was about 1320 on the #5 cylinder. Most were in the mid to upper 1200's.
For thought / strategic tuning provoking purposes only - If power output starts to dive as you get near the high 10's A/F, but more fuel is safer on pistons and valves, where does cylinder washing, and oil contamination concern start? Advancing timing definitely saves the exhaust valves as others have mentioned, but can increase cylinder pressure which has multiple consequences. This is where one might say EFI has a protection advantage with a full time knock monitor. And helps when tuning with fuel and air temperature 30 degree's possibly warmer than dyno. Bu EFI doesn't have a venturi with fuel further cooling the airtrac as far upstream as possible. In my carb'd blow thru boosted Cobra, i'm adding a knock sensor with external LED on dash. Might be something to think about for the final tuning.
Thanks for posting these type of builds. Very cool and hope to see some video's or at next's year NIOC Thunder Run.
10-03-2014, 10:26 AM
#37
I have no experience with setting up a knock system on a carb deal. Although, i have heard that for it to really work like say a stock LS1 management , it takes a whole lot of setting up. Things like deciphering at what frequency knock is actually taking place. Where knock occurs in say a supercharged 540ci marine engine may not produce the same harmonics as a factory LS1 engine. The last thing i want is to record false knock, and have my ignition pull timing away while at wide open throttle.
That stuff is over my head though. Something for the experts to answer. Heck im still in the world of playing with carb jets
That stuff is over my head though. Something for the experts to answer. Heck im still in the world of playing with carb jets
10-03-2014, 01:01 PM
#38
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I have no experience with setting up a knock system on a carb deal. Although, i have heard that for it to really work like say a stock LS1 management , it takes a whole lot of setting up. Things like deciphering at what frequency knock is actually taking place. Where knock occurs in say a supercharged 540ci marine engine may not produce the same harmonics as a factory LS1 engine. The last thing i want is to record false knock, and have my ignition pull timing away while at wide open throttle.
That stuff is over my head though. Something for the experts to answer. Heck im still in the world of playing with carb jets
That stuff is over my head though. Something for the experts to answer. Heck im still in the world of playing with carb jets
http://www.knocklink.com/KnockBlock.html
http://www.phormula.com/Default.aspx
10-03-2014, 01:27 PM
#39
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When we ran knock sensors on carbed blowers with distributors, there was an MSD module that plugged in to their box and would pull 5* out if it showed a knock from the sensor. Extremely low tech but a good investment at the time.
A fella told me once that setting up a blower in a boat is unique, because the load on a boat is like a car running uphill, pulling a trailer, all the time! So much more is available with the new EFI stuff it's amazing.
A fella told me once that setting up a blower in a boat is unique, because the load on a boat is like a car running uphill, pulling a trailer, all the time! So much more is available with the new EFI stuff it's amazing.
10-03-2014, 02:05 PM
#40
The question is, was it really working as it should.
I may start another thread on this timing topic. I really dont want to derail this thread into a timing debate. Lots of good stuff about this build in other areas
I will say this though, this is definitely not the first marine blower setup this group of fuktards has done. Ive got a pair of 800hp blown 468s i been beating on for a long time, icdedppl has twin 900hp 540s, mike tkach had 950hp 540s on his cat he built that never skipped a beat, and now 1200hp whippled 588's. Not to mention mike and the race shop where we dyno have belted out quite a few over the years too. But i am all for learning new tricks. Just because my engines havent blown up, doesnt mean i still cant improve them or factor in some safety to them.
The purpose of this thread was to give a result of a parts combination that worked well. Slap some edelbrock heads on this build, a shelf comp hyd roller, a pair of molested 750 carbs, and it would have struggled to make 750hp.
Im gonna start another thread regarding a programmable timing control and knock systems for engines like this. Id like to talk about the benefits of something like the daytona sensor ignition , etc. Im considering getting into that part of playing with these builds. Andy motorman id love to hear your input when i do. You are a sharp dude !
I may start another thread on this timing topic. I really dont want to derail this thread into a timing debate. Lots of good stuff about this build in other areas
I will say this though, this is definitely not the first marine blower setup this group of fuktards has done. Ive got a pair of 800hp blown 468s i been beating on for a long time, icdedppl has twin 900hp 540s, mike tkach had 950hp 540s on his cat he built that never skipped a beat, and now 1200hp whippled 588's. Not to mention mike and the race shop where we dyno have belted out quite a few over the years too. But i am all for learning new tricks. Just because my engines havent blown up, doesnt mean i still cant improve them or factor in some safety to them.
The purpose of this thread was to give a result of a parts combination that worked well. Slap some edelbrock heads on this build, a shelf comp hyd roller, a pair of molested 750 carbs, and it would have struggled to make 750hp.
Im gonna start another thread regarding a programmable timing control and knock systems for engines like this. Id like to talk about the benefits of something like the daytona sensor ignition , etc. Im considering getting into that part of playing with these builds. Andy motorman id love to hear your input when i do. You are a sharp dude !
