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All the parts for the new 'bits n pieces' engine are with the engine builder and new seals etc are ordered.
He thinks what I've done is "worth a try" !
This might be happening fairly soon .....
Been thinking about what to do about intake and exhaust manifold and come to conclusion that a really good comparison can be made if I just use the same basic specs that the Mazda race series guys use = basically stock intake and manifolds with a free flow exhaust.
I have multiple dynos of stock engines with this setup so a direct comparison will show for definite if any gains have been made.
New engine not ready yet but I did manage to get Bluey out on the track last weekend and lined up a couple of lightly modified Rx8s for a roll race.
Pulled a couple of car lengths over them from 2nd through 3rd (even had a passenger vs none in the other cars).
why not make and post a time log on a reasonably flat/level road from 3000 - 8000 in 2nd gear?
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That log wouldn't tell you anything.
As Ive mentioned before, it doesn't start pulling on a stock engine till AFTER 8000rpm and below about 5000 it's actually a little slower.
In a drag race ..... I'm revving to 9000 plus and in 2nd gear and it may have pulled less than half a car. It's after changing to 3rd is when I really see a difference.
Maybe you forgot ..... I posted a dyno of my engine vs race prepped stock engine (done on the same dyno on the same day) several pages back . That is the absolute best way to evaluate it.
What you are asking is pretty Micky Mouse IMO but .....whatever makes you happy ...lol
x axis is time
Inlet air temp was 20C
Humidity no idea
Weight stock plus all the extra mazdaspeed bodykit. Unsure of how much gas in tank. I weigh 85ish kgs
Wind no idea but probably negligable.
pretty level road IIRC
Recording variables......... as you can see, it jumps around a bit at high rpm for whatever reason.
A few variables there ............ Dunno how you can expect to make a valid comparison with that.
Maybe you forgot ..... I posted a dyno of my engine vs race prepped stock engine (done on the same dyno on the same day) several pages back . That is the absolute best way to evaluate it.
What you are asking is pretty Micky Mouse IMO but .....whatever makes you happy ...lol
x axis is time
Inlet air temp was 20C
Humidity no idea
Weight stock plus all the extra mazdaspeed bodykit. Unsure of how much gas in tank. I weigh 85ish kgs
Wind no idea but probably negligable.
pretty level road IIRC
Recording variables......... as you can see, it jumps around a bit at high rpm for whatever reason.
A few variables there ............ Dunno how you can expect to make a valid comparison with that.
Can you clarify? I see no units of time in your graph.
Yeeeesh, the guy makes a modest post to show that his latest idea/engine is still in the works but isn't done yet, adds some filler about an observation of his mini BP engine on the track, and now you all need NASA's analytical breakdown of the pull. It's already mentioned that there is a dyno chart in an earlier post for that engine and he posted a screenshot of exactly what was asked for. The points are in obvious 0.1s intervals, eyeball it. None of you are going to replicate this mini BP anyways and we don't know anything about the condition of the other "lightly modified" cars, so what would the exact info tell you? You gonna compare it to an RPM vs time of your own cars under completely different conditions?
I just want to get a feel for it and my request was intended for when it’s completed. I understand temperature, weight, etc. variables and such, but unless it’s far from sea level then given my own experience I believe a reasonable assessment can be made.
I even posted my own logs as examples in the diyman hybrid thread. Not looking to knock it down if it’s real, but what I’m asking for is more relevant than talking about “gapping” another RX8. The internet is full of that lip service along with empty brapping, BPd, etc. worship and nothing at all to back it up or to assess by. Time vs moving speed is a true measure of acceleration regardless. It’s not like an NA RX8 is going to spinning tires on flat, dry pavement in 2nd and higher gears.
It’s much easier to see and assess in actual values than trying to line up points on a graph imo. Maybe my annoyance is showing through a bit, but just been through this too many times on here over the many years.
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Yeeeesh, the guy makes a modest post to show that his latest idea/engine is still in the works but isn't done yet, adds some filler about an observation of his mini BP engine on the track, and now you all need NASA's analytical breakdown of the pull. It's already mentioned that there is a dyno chart in an earlier post for that engine and he posted a screenshot of exactly what was asked for. The points are in obvious 0.1s intervals, eyeball it. None of you are going to replicate this mini BP anyways and we don't know anything about the condition of the other "lightly modified" cars, so what would the exact info tell you? You gonna compare it to an RPM vs time of your own cars under completely different conditions?
Couldn't have put it better myself . Thanks RMRx .
Also : new engine will go in another car so I'll start a new thread for that when I have it. I'll only go to the trouble of dynoing it if i know it will (Quoting Team here) "gap" a stock rx8. I wont be falling into the trap of trying to compare it by using the BS method being proposed here.
Team and I disagree a fair amount, but I agree with him here: time/speed is handy and useful. I would much rather see such a raw log than a VD dyno graph, for instance, even though I like to use VD myself.
Again, I agree with him-It's not NASA stuff either, and can be pretty repeatable and consistent, even on the other side of the world.
It not a Mickey Mouse Method in my opinion.
Last edited by kevink0000; 12-04-2022 at 06:55 AM.
And, I am looking forward to Brett's next build, and whatever idea he has cooked up, I'm sure it will be interesting. It all adds up, it never takes away...
Team and disagree a fair amount, but I agree with him here: time/speed is handy and useful. I would much rather see such a raw log than a VD dyno graph, for instance, even though I like to use VD myself.
Again, I agree with him-It's not NASA stuff either, and can be pretty repeatable and consistent, even on the other side of the world.
It not a Mickey Mouse Method in my opinion.
I have used virtual dyno myself thousands of times ,possibly more than anyone else on here. It is based on the very same measurements and yes it can be useful for seeing if you have made 10 plus whp improvements on the SAME car , at the SAME weight , on the SAME stretch of road running in the Same direction , In the SAME conditions.
When paired with the knowledge you gain from also doing a proper dyno on that same car ...it's even possible to obtain contain consistent results within 5-10 whp of that dyno.
For comparing with a different car, in a different country, with different tyres, under different conditions, at a different weight on a different stretch of road ...and trying to spot differences across a narrow part of the rev range it's about as Mickey Mouse as it gets.
I have used virtual dyno myself thousands of times ,possibly more than anyone else on here. It is based on the very same measurements and yes it can be useful for seeing if you have made 10 plus whp improvements on the SAME car , at the SAME weight , on the SAME stretch of road running in the Same direction , In the SAME conditions.
When paired with the knowledge you gain from also doing a proper dyno on that same car ...it's even possible to obtain contain consistent results within 5-10 whp of that dyno.
For comparing with a different car, in a different country, with different tyres, under different conditions, at a different weight on a different stretch of road ...and trying to spot differences across a narrow part of the rev range it's about as Mickey Mouse as it gets.
Well, I don't feel a need to continue argue the point, I am content to disagree and let it lie after saying the following: I haven't tuned hundreds of cars via laptop like yourself, but I have tuned or been involved with the tuning of maybe a couple dozen bikes, back in the pre-Dynojet (meaning inexpensive dyno runs) days of carburetors and stopwatches. Myself, and others, would make changes (porting, jetting and even cam timing ) and test ideas this way before going to the dragstrip (mostly) or road course. Time/speed was useful then, and its useful now. If you have used it more than a few times, you would know how surprisingly robust a method it is. So again, not Mickey Mouse, but, to each his own.
Well, I don't feel a need to continue argue the point, I am content to disagree and let it lie after saying the following: I haven't tuned hundreds of cars via laptop like yourself, but I have tuned or been involved with the tuning of maybe a couple dozen bikes, back in the pre-Dynojet (meaning inexpensive dyno runs) days of carburetors and stopwatches. Myself, and others, would make changes (porting, jetting and even cam timing ) and test ideas this way before going to the dragstrip (mostly) or road course. Time/speed was useful then, and its useful now. If you have used it more than a few times, you would know how surprisingly robust a method it is. So again, not Mickey Mouse, but, to each his own.
Did you even read what I wrote above? I didn't say it was Mickey Mouse when used that way, only when used in the way Team proposes to.
Did you even read what I wrote above? I didn't say it was Mickey Mouse when used that way, only when used in the way Team proposes to.
I did read it, and I am agreeing with Team. A log would produce some useful info, even with all the variables you cite. Like I said, it is surprising to see how robust a method it is, within reason.
I did read it, and I am agreeing with Team. A log would produce some useful info, even with all the variables you cite. Like I said, it is surprising to see how robust a method it is, within reason.
Can't believe what I'm reading ..but hey ...you can believe whatever you want.
Well , when and if you ever get to test (with VD) dozens of RX8s under different conditions for yourself (as I have), maybe you will see some sense then.
Well , when and if you ever get to test (with VD) dozens of RX8s under different conditions for yourself (as I have), maybe you will see some sense then.
And VD introduces artifacts that are not in the log file. It's useful, but to compare what i am saying about time/speed with VD usage are really two different things in my opinion. In VD, turn off smoothing, Now, where did all that come from?
There are a number of ways to compare the power/acceleration of one vehicle vs another, some not so accurate and some very accurate. Accuracy improves as variables are reduced!
1/The least accurate method has the most variables .... that would be the method Kevin and Team talking about. Raw numbers of speed vs time for two different vehicles in different locations. They might be the same make and model vehicle with the same gear ratio, which eliminates at least some variables but several other major variables are uncontrolled. EG weight, road condition , atmospheric conditions, tyre diameter, Cd . All of these can affect the result by themselves but in combination the can potentially have a huge effect on the result.
Obviously , when you are comparing a vehicle with itself (as Kevin mentioned with his motorbike experiments) you have eliminated all the above, assuming you use the same stretch of road and test in both directions. BTW..... There are good reasons why all world speed records etc require passes in both directions ...think about that for a moment.
2/ A better way is to use virtual dyno . It's more accurate than '1' because it removes some variables IE Weight(if accurate) , tyre diameter and Cd . And if you are careful about how you do your logs it can be very repeatable. For example , always same amount of gas in the tank , always done within a few degrees temp, always done on same flat, level stretch of road with no head or tail wind. Comparing vehicles in different locations is still pretty inaccurate because it requires both operators to have the same methodology and choose the perfect stretch of road.
Kevin's note about smoothing .... all that is doing is taking the jerky nature of the raw data and averaging it out , take a look at the chart I posted above and you can see why that is necessary. This is something you cant do using method '1' and this actually makes that method even LESS accurate. Especially if you happen to grab a rouge datapoint.
3/ An actual Dyno . Next most accurate because it removes all the environmental variables mentioned above . As we know this method isn't perfect either as there can be variation between dynos. but it's a huge improvement over either of 1 or 2 .
Putting two vehicles on the same dyno on the same day eliminates that variation altogether though so if that was done there can be no argument about that particular comparison.
4/ A roll race . A roll race between two identical vehicles with the same gear ratios and weight would take the comparison to another level again as we get to see reality with almost all variables removed and not just numbers.
Now getting back to what I've done in this thread to try and demonstrate the SMALL gains made with the engine. Firstly I did Virtual dynos to get some feel if there was any gain, those weren't saying much but did offer that it at least was a decently strong engine, then I did an actual dyno and overlaid that with a car with a race prepped engine ON THE SAME DYNO ON THE SAME DAY !!!!!
Then I mentioned that I had some roll races with other lightly modded rx8s . Races which actually backed up everything that was shown on the dyno IE no gains till 8000 plus rpm.
So I've done the three most accurate methods for comparing vehicle performance mentioned here and only ever claimed very modest gains. But no........... that's not good enough for some. They want to use the absolute LEAST most accurate method as well.
Kinda makes one wonder about the motivations of those people.
10-17-2022, 10:40 PM
) and test ideas this way before going to the dragstrip (mostly) or road course. Time/speed was useful then, and its useful now. If you have used it more than a few times, you would know how surprisingly robust a method it is. So again, not Mickey Mouse, but, to each his own.