Strokercharged95GT 13b-REW Build - Page 11 - RX8Club.com



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Old 06-01-2018, 08:07 PM   #251  
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Do you have a filter type buffer in the boost line to the computer? I have a couple inliine on mine and it makes those type of spikes a lot less of a problem.
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Old 06-01-2018, 08:48 PM   #252  
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For dwell you should put like 4.5 up to 3000rpm and lower the dwell progressivly to 2.5 in boost and at high rpm, the faster the engine goes the less time the coil have to charge and if you put high dwell itll put alot of heat into them
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Old 06-01-2018, 10:49 PM   #253  
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Quote:
Originally Posted by dannobre View Post
Do you have a filter type buffer in the boost line to the computer? I have a couple inliine on mine and it makes those type of spikes a lot less of a problem.
I just have the one that came with the adaptronics installed a few inches before the port on the ECU. I try to find another and add it in to see if it makes a difference...

As far as dwell, I may try to lower it some more below 4.0ms in the upper RPMs since I have confirmed no misfires at 11:1 AFR, 18 psi, and a good deal of water.

Somebody was asking about videos in PM's. So here are just a few of the tamer ones.

BP idle

Lugging 3rd gear pull to 6,200 RPMs

Last edited by strokercharged95gt; 06-03-2018 at 08:44 AM.
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Old 06-15-2018, 09:36 PM   #254  
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Update: Decreased dwell from 4.5ms to 3.5ms across the board. Removed a bit of the water (down to 750cc/min of water/methanol. Did a 3rd gear pull from 60mph to 90mph, and had no ignition breakup on the run. From the graph I still have to add a few percent of fuel above 6,200 RPMs to compensate for the decrease in methanol.

Now that I am putting less stress on the coils, I hope I can get them to last more than a thousand or so miles...

Based on the log, I am at 77mph at 6,200 and 90mph at 7,200. This would put the car somewhere around 103 mph at the top of third (8,200). It would make perfect 1/8th mile gearing if I could really get the horsepower up and keep it all together.


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Old 06-24-2018, 08:43 AM   #255  
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Did a 30-120 mph pull (on the dyno of course). Its hot and humid right now. Began the pull rolling into 2nd gear and only started spinning the tires just below 7,000 (can see squiggly RPM/speed line at 60-67 mph). Also had a little tire spin going into third, but quickly got planted. I will probably set 45 DC (17 psi) as max for second gear when running street tires. I am on street tires, because I have already worn my drag radials down to about 50% tread.

Duty Cycle at 45% which logs at 17 psi.
On this pull I was injecting about 650-700 cc/min of 50/50 meth/water (2:1 into turbo compressor vs UIM).
Timing was somewhat conservative at 12-13 degree's total.
Max knock values in the 20-30 range, which is seems to be just normal engine noise.
Intake Air Temp (IAT) at 110 F at start of run, and it 138 F at middle of 4th gear (120 mph).
Car started to lean up (11.7-11.8) a tad from 110-120 mph, but still likely safe with water/meth (will add some VE above 6,300)
Had to let off because piece of inner fender well broke loose and started rubbing the tire.
All in all car is real smooth, will start adding duty cycle in 3rd and 4th gear to bring up the power. The heat sucks right now.


Last edited by strokercharged95gt; 06-29-2018 at 09:11 AM.
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Old 07-01-2018, 09:43 AM   #256  
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Update: Some more data.

30-130 mph pull (still on the dyno). Had to let off because I was running out of dyno. Ambient temp was 85 degrees.

Pretty much spun the tires all the way through 2nd gear, had to short shift into third.

Duty Cycle is at 52 (3rd and 4th gear only), which is about 19 psi (only one row in log above 20 psi). Boost drops to 18 psi near redline.

On this pull I was injecting about 850 cc/min of 50/50 meth/water (2:1 into turbo compressor vs UIM).

Timing was somewhat conservative at 10-11 degree's total.

Max knock values in the 20-30 range, which is normal for this engine.

Intake Air Temp (IAT) at 107 F at start of run, and it 147 F at near top of 4th gear (130 mph).

Car was rock solid on the AFR, o2 was reading between 10.7-11.2 through the important parts of the run.

With 3.5 ms dwell on the D585 I had no sign of breakup or hesitation of any kind.

Must fight the urge to keep turning it up. Here is the graph and a partial log.

You can see how the backfire during gear changes shows up on my knock log.

Also I am using only 40% of the 1000cc secondary injectors, so fueling isn't an issue. Based on the calculations I have seen, I should conservatively enough injector to get to 550-575 rwhp (doesn't consider methanol either).

In the log you can see I'm gaining nearly 10 mph per second above 80 mph.




Last edited by strokercharged95gt; 07-01-2018 at 10:14 AM.
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Old 07-03-2018, 10:57 AM   #257  
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Looking for some advice. I have never had this car to the track or have launched hard on the drag radials. Unless something comes up or it rains on Thursday, I will be heading down to Bradenton 1/4 mile to get some shakedown passes done in the 8. Obviously with street tires and lack of traction, I have never really feared any drive-train problems. Launching at a prepped track on MT drag radials is a whole other animal.

My plan is to have the 2-step up at 5500-6000, and will try and let the clutch out in a controlled manner until the car is moving and planted. Obviously my 60 foot will suffer, but I also don't want to blow my car up on the first launch. I assuming that any type of clutch drop will be instant kill to the axles or rear end.

Has anyone launched a rx8 on some sticky tires with any type of power? Can anyone attest to the strength of the rear axles or rear end? Appreciate any thoughts...
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Old 07-03-2018, 03:47 PM   #258  
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Axles seem to be the next weakest link after the stock 6 speed. The rear ends are quite hard to break.



I would think that you need to be careful dropping the clutch while really hooked up.....



I guess the good thing is that taking out an axle really doesn't do too much other damage The fun part is driving home.......
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Old 07-03-2018, 06:42 PM   #259  
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After paying $175 to have my car towed home one time from the track, I now have AAA gold and get 4 tows of 100 miles per year.

The clutch has about a 1/2-inch of engagement and grabs hard. If I leave on low RPMs, it will be a guaranteed bog and the run will have a dismal ET. If I leave on high RPMs, and get too aggressive with clutch, I surely will snap an axle because these tires hook. The only way I see that I can get a decent launch and not break something will be to leave at moderately high RPMs, hold the clutch at half engagement let it chatter a bit while the car gains a few mph then side step it. Either way I will be filming it all so it may be the shortest run ever if carnage ensues....
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Old 07-06-2018, 06:55 AM   #260  
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Yesterday was a complete bust. Was a 30% chance of rain in Tampa and Bradenton I left for the track yesterday afternoon. Its 65 miles round trip to track from my house. I got 5 miles from the track and it started pouring and the whole sky turned black. Turned around and drove another 90 minutes home in some of the worst rain ever. Luckily, I decided against driving to the track with the drag radials on. Weathermen don't know ****.
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Old 07-06-2018, 12:34 PM   #261  
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Stroker,

What is your primary inj. duty so high and secondary inversely so low? I'd want to dial the primaries back to get them around 80%, pumping more through the secondaries.

Have you played with leading/trailing split at all, swinging it a couple degrees each way to see if there is any change in AFR or EGT's?

Do you mind explaining the normality of the knock readings? That seems incredibly high, but I may be mis-interpreting the knock values from my experience tuning via piston engines like the SkyActiv 2.0 compared to a rotary.

EDIT: Likely already mentioned by someone else, but that RX-8 5spd center-section looks identical to the FD transmission (similar bell as well), major difference seems to be in the tail shaft assembly.

Last edited by furansu; 07-06-2018 at 12:37 PM.
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Old 07-10-2018, 07:29 AM   #262  
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What is your primary inj. duty so high and secondary inversely so low? I'd want to dial the primaries back to get them around 80%, pumping more through the secondaries.

Adaptronics controls all of the injection duty cycling. It ramps up from P1 to P2 to Secondaries from 0-95%. They are all ID injectors that seem to have no problem handling the high duty cycle. Since I have been able to produce a relatively flat A/F curve, I see no need to make changes.

Have you played with leading/trailing split at all, swinging it a couple degrees each way to see if there is any change in AFR or EGT's?

I have tried different splits, I have found that I had the least audible knock(s) during tuning with a 12 degree split in the areas of highest load.


Do you mind explaining the normality of the knock readings? That seems incredibly high, but I may be mis-interpreting the knock values from my experience tuning via piston engines like the SkyActiv 2.0 compared to a rotary.

I have tuned my mustang without a knock sensor for more than a decade. It is right about 11:1 compression with up to 9 pounds of boost. I went through about 6 head gaskets on that motor which is still running. I have become an expert on lifting on audible knock. For the 13b motor, when I hear audible knock the values have been like 100-250 (when I chipped my apex seal racing I logged somewhere around 250). You can see a full blown backfire between shifts knock is hitting around 100. So when I see those 20-30 counts under full load with no audible knocking, breakup, or power loss, I am not worried at all. It is likely the knock sensor picking up the waste gate, maybe an exhaust leak, or some other engine noise.


EDIT: Likely already mentioned by someone else, but that RX-8 5spd center-section looks identical to the FD transmission (similar bell as well), major difference seems to be in the tail shaft assembly.

I have a FD transmission that came with my blown REW engine that is currently a backup to my rx8 5 speed. I will swap the bell-housing (rx8 push clutch vs FD pull clutch) and tail shaft when/if the time comes. I remember when people said I got ripped off buying a core REW engine with FD transmission for $1,350.00 shipped, now they are $3-4k on ebay all day long.
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Old 07-10-2018, 10:18 AM   #263  
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Quote:
Originally Posted by strokercharged95gt View Post
Adaptronics controls all of the injection duty cycling. It ramps up from P1 to P2 to Secondaries from 0-95%. They are all ID injectors that seem to have no problem handling the high duty cycle. Since I have been able to produce a relatively flat A/F curve, I see no need to make changes.
Ah okay -- I am not familiar with Adaptronics in the least, other than that they are quite popular with custom rotaries.

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Originally Posted by strokercharged95gt View Post
I have tuned my mustang without a knock sensor for more than a decade. It is right about 11:1 compression with up to 9 pounds of boost. I went through about 6 head gaskets on that motor which is still running. I have become an expert on lifting on audible knock. For the 13b motor, when I hear audible knock the values have been like 100-250 (when I chipped my apex seal racing I logged somewhere around 250). You can see a full blown backfire between shifts knock is hitting around 100. So when I see those 20-30 counts under full load with no audible knocking, breakup, or power loss, I am not worried at all. It is likely the knock sensor picking up the waste gate, maybe an exhaust leak, or some other engine noise.
Okay, I guess the knock counts are more detailed in Adaptronics than I'm used to with the Sky-G tuning (Similar to Subaru logic) I've done. Usually knock events are binary, either it is knocking or it isn't, with knock significance measured in how many degrees of timing the ECU pulls. Sky-G method is to threshold knock constantly, trying to find the most efficient timing the engine will tolerate. They will slowly add in .25 degrees of timing until knock is identified, then it'll pull back .5-1* of timing for that cell where knock presented.

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Originally Posted by strokercharged95gt View Post
I have a FD transmission that came with my blown REW engine that is currently a backup to my rx8 5 speed. I will swap the bell-housing (rx8 push clutch vs FD pull clutch) and tail shaft when/if the time comes. I remember when people said I got ripped off buying a core REW engine with FD transmission for $1,350.00 shipped, now they are $3-4k on ebay all day long.
Eh, I'd say it is fair -- FD and FD parts pricing is retarded these days. My 94' was automatic, so I bought all of the parts to convert for around $1,300, keep in mind this was back in 2003/2004. The transmission, driveshaft, clutch+brake pedal, shifter, shift ****, stock flywheel, and a new ACT Street/Strip clutch was $800 all in, then I added a Racing Beat lightweight flywheel, new 5th gear synchro, new fluid, and some wiring odds and ends. $1,350 for a 'full assembly' of engine and trans (turbos, wiring, etc) seems good to me in the current climate.

Thank you for the added details, I've never done a calibration a rotary before, so I still have lots to learn.
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Old 07-10-2018, 10:52 AM   #264  
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Okay, I guess the knock counts are more detailed in Adaptronics than I'm used to with the Sky-G tuning (Similar to Subaru logic) I've done. Usually knock events are binary, either it is knocking or it isn't, with knock significance measured in how many degrees of timing the ECU pulls. Sky-G method is to threshold knock constantly, trying to find the most efficient timing the engine will tolerate. They will slowly add in .25 degrees of timing until knock is identified, then it'll pull back .5-1* of timing for that cell where knock presented.
I believe in a rx8 the knock sensor is little more than an engine stethoscope that converts engine loudness (certain frequency) into a number. In Adaptronics, you can set a base knock curve. So if in normal engine operation you get a normal knock count of 50, you can set your base knock to 50. So if you get a 50 knock count, it will actually show up in the log as "0". If you get a "75" knock count, it will show up as 25 (75 read-50 base). I have my base knock set real low so its very common to see 10-30 on my logs. I could set base knock higher so everything would read "0", but then I wouldn't have confirmation that the knock sensor was working. I do have a fail-safe that if I get over 50 knock that I retard ignition 5 degree's and enrichen fuel 10%. This however failed to save my motor when I chipped an apex seal. Even with a 250 knock event and a huge timing pull by Adaptronics the damage was already done. I may have been able to lift if I could have heard the knock event, but the damn mustang next to me was so freaking loud.
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Old 07-19-2018, 09:14 PM   #265  
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Update: Some more data.

40-100ish mph pull. Ambient temp was 83 degrees.

Duty Cycle is at 52 (3rd and 4th gear only), which was about 21 psi on this pull.

On this pull I was injecting about 1000 cc/min of 50/50 meth/water (2:1 into turbo compressor vs UIM).

Timing was conservative at 8-9 degree's total.

No significant knock under WOT

Intake Air Temp (IAT) at 107 F at start of run, and it 136 F just into 4th.

AFR was reading between 10.6-11.6 through the important parts of the run.



Even at 21 psi the car didn't feel as fast as the previous pull so I reviewed the logs to see what the data says.

On my previous 19 psi pull my delta x(RPM)/ delta t(time) was on average through 3rd gear at 732, which means I'm gaining 732 RPMs per second. From 0 to 8,000 RPMS the car will go from 0-100 mph (roughly) which means 1 mph per 80 RPMs.

I took the log data, specifically the delta x(RPM)/ delta t(time) (from 5,200-7,200 RPMs) in 3rd gear in all 3 logs and the data was as follows.

So for 17 psi - 686 RPMs per sec/80 = 8.56 mph/s acceleration
So for 19 psi - 732 RPMs per sec/80= 9.15 mph/s acceleration
So for 21 psi - 772 RPMs per sec/80 = 9.65 mph/s acceleration

Seems that I am seeing some slow down in acceleration per psi based on those calculation and maybe approaching the efficiency limit of the turbo. I would like to get a pull at 23 psi and see what the new data will tell me....

Then I got real bored and decided to plot those calculations on a graph with a logarithmic trendline to estimate what kind of turbo output I would need to increase my acceleration.

Here is the graph.



Based on the graph, I would need to upwards of 32-33 psi to get to 12 MPH/S in third gear. I know that this curve doesn't not take into account all the extra heat the turbo will make and the drop in efficiency (this estimate assumes linear efficiency drop), but its about as much as I can work with. I bet with more data points the line would begin to flatten out. Being that third gear on a perfect shift goes from 70-102, it would be nice to burn through the gear quickly.

This is the only way I could really think of determining whether I'm picking up or losing power on runs, anyone have any better methods they have in trying to interpolate the data?

Last edited by strokercharged95gt; 07-19-2018 at 09:22 PM.
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