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shay2nak
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Discussion Starter #1
So i had the car retuned last year and everything went great. Then after a few months I went to a local dyno to make a final measurement and it was completely off.

Retuned the car a couple weeks ago. Again everything went great. Then this morning did a final dyno and was still messed up.

Other than the ECU itself, i really don't know what it could be. The pulley is not slipping and there is no boost leak, otherwise I wouldn't get the numbers I did during the tuning session.

Look at the dynapack as it was done when tuned. The blue/green curve is what I had before with the stock pulley. The yellow is what I got from tuning with 3.1. pretty kick ass, right? :D

Now the dynojet, the blue curve is the same tune as the blue/green curve in the dynapack. You can see they are very close. The red is the tuning from last year with the 3.1 and the green is the one from today's pull. The black curve is what I should be getting based on the dynapack measurements. Should be at least +275whp.

So any ideas? I don't have a spare ecu to try. I still have the stock clutch, but the only thing I can do is eliminate the dyno. I'll be going back to the dynapack and see what I get there, but I can tell you this car should be fast as sh*t and should be scaring me. 20wtq is A LOT. I felt a 10wtq difference before, this one should be really obvious.

this is really messed up. I was sure it was alright this time around. Pretty sh*tty. The reflash last year, we had to crack the ECU open to do it. 2nd time around we did it through the OBD port.


HELP!!!!!!!!!!!!!!!!
 

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Ara,
I'm confused. the first dyno plot says flywheel H.P and the second is WHP.

Is that correct ? Anyway I stuffed my ecu up as well. Too much fiddling around, should have left it stock.
 

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There are lots of reasons for reduced HP outside of a bad ECU. In some cases the ECU may reduce timing due to triggers from the knock sensor, which will cause a reduction in HP. Oil coating the inside of the intercooler, causing higher Intake Air Temperatures IAT (I see you have a catch can). Bad Oxygen sensor, bad Mass Airflow sensor MAF. A catalytic converter which has become baked due to higher heat from the supercharged exhaust (saw that one at Inde Motorsports a couple months ago). But at the end of the day, dynos are not great for absolute measurements, just relative measurements on the same day, under same temperature and tire conditions. I have seen people lose 10HP from just a difference in tire type and inflation.
 

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Plug Whisperer
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Comparing apples and oranges. Making about the right power for your mods on a dynojet...
 

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shay2nak
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Discussion Starter #5 (Edited)
I only have 2 options right now.

1) I will go back to the dynapack and see what I get there. If it's less than what I got in the yellow plot, then the ECU must be f*cked.

2) I need a new ECU to flash.

3) It could be the O2 on the U-bend. The shop removed it to place the wideband, instead of removing the bolt on the header. I have 16k miles, don't think that O2 would be bad?

Ara,
I'm confused. the first dyno plot says flywheel H.P and the second is WHP.

Is that correct ? Anyway I stuffed my ecu up as well. Too much fiddling around, should have left it stock.
ignore that, it's whp.

what happened to your ECU?


There are lots of reasons for reduced HP outside of a bad ECU. In some cases the ECU may reduce timing due to triggers from the knock sensor, which will cause a reduction in HP. Oil coating the inside of the intercooler, causing higher Intake Air Temperatures IAT (I see you have a catch can). Bad Oxygen sensor, bad Mass Airflow sensor MAF. A catalytic converter which has become baked due to higher heat from the supercharged exhaust (saw that one at Inde Motorsports a couple months ago). But at the end of the day, dynos are not great for absolute measurements, just relative measurements on the same day, under same temperature and tire conditions. I have seen people lose 10HP from just a difference in tire type and inflation.
I have catch cans so no oil in IC pipes. I check IAT with my OBD reader. The MAF was recently cleaned. Could be the O2, but doubt it. Everything is in working order.

THe beauty of the plots I posted is that I have a baseline for each. As I said before, the BLUE curve on each plot IS THE SAME TUNE I had done in 2009. I had the ECU flashed on the DYNAPACK and then I went to my local DYNOJET to make the measurement.

Comparing apples and oranges. Making about the right power for your mods on a dynojet...
how can I be making less power than before with a smaller pulley & 550cc? I have modded everything but the motor itself. This should be well over 300crankhp. So you're saying that the dynojet reads 45whp LOWER than the dynapack? No way. Look at the blue curves on each...they are very close. I got almost 285whp on the Dynapack after 3 hours of pulls. Which could easily translate into +280whp on my Dynojet.

As I said before, the BLUE curve on each plot IS THE SAME TUNE I had done in 2009. I had the ECU flashed on the DYNAPACK and then I went to my local DYNOJET to make the measurement. So, the YELLOW curve (new tune) on the dynapack which is much higher than the BLUE baseline curve, one can make an educated guess that the chance is 100% that a measurement of a dynojet will yield a higher result than the BLUE baseline curve.

It is possible to get ~285whp with a 3.1" pulley.
 

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Everyone has pretty much chimed in here. You are trying to compare 2 different dynos on many different days and extrapolate that your car will make 280whp. As phil stated, its apples to oranges.

Dynos read differently, they always will. The general rule of thumb (this doesn't mean it applies to every dyno of every type) is that dynapacs tend to read a little higher than a Jet. Additionally although dyno ambient corrections attempt to equalize things, engines still produce different results under different conditions... and of course you are doing doing dyno pulls on different days where conditions are different. IAT temps can make a DRAMATIC difference in power, let alone a small leak, or intercooler efficiency due to oil, etc. etc.

Seems to me you are mad you didn't get to 280whp. So what?
I have tuned a few cars where the owner thinks, it should do this or that based on my paper analysis. And my response is, well it didn't. I have literally said:
"The dyno is simply a tool to measure relative power/torque. If it makes you feel any better download photoshop and add 5% more torque on to the numbers and reprint. It will make you feel better but it won't make the car any faster. At the end of the day we race cars not dynos."
 

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I will say I missed that and it does seem a bit strange. Although realize you are still relying on your original dyno results on the Jet as gospel...

What tune exactly is in the car? And do you have ANY other data to back up the dyno pulls?

You would really need more data to find out if the power is correct or missing due to an issue. Namely it would be nice to see manifold pressure, iat temp, ignition timing, knock, and AFR. Its very rare to see and ECU that just looses it brains (it's tune) over time. Almost always it is something in the tune either desired (such as ignition timing pull due to knock or AIT), or undesired that will cause a change in power.
 

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Its really difficult to simply download a tune and expect it to work well if you change to bigger injectors, smaller pulley and headers. Plus the fact that I live in Australia, there are too many variables. I just junked by tune and I'm getting the new SSC stand alone ecu which can be adjusted by my local dyno shop.
 

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shay2nak
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Discussion Starter #12 (Edited)
I will say I missed that and it does seem a bit strange. Although realize you are still relying on your original dyno results on the Jet as gospel...

What tune exactly is in the car? And do you have ANY other data to back up the dyno pulls?

You would really need more data to find out if the power is correct or missing due to an issue. Namely it would be nice to see manifold pressure, iat temp, ignition timing, knock, and AFR. Its very rare to see and ECU that just looses it brains (it's tune) over time. Almost always it is something in the tune either desired (such as ignition timing pull due to knock or AIT), or undesired that will cause a change in power.
this was a custom Gotham tune. Someone came and we spent 3 hours tuning the car at a local shop. I tried to get the A/F, but apparently the goddamn thing wasn't hooked up to read even though the tech placed the sensor in the exhaust. :wallbang:

The IAT was fine. started below 77 and went up from there. I just did one pull after I found it was f*cked. Well at least the XO point showed correct. LOL we lowered it to 5k from 5400.

This is the second tune for the 3.1, so I really don't know...I'm just going to have to try one thing after another and eliminate each until I find the culprit.

I tried to use the shop with the dynojet for the retune, but they were not available during that weekend, so I was forced to go back to the shop with the dynapack.

Its really difficult to simply download a tune and expect it to work well if you change to bigger injectors, smaller pulley and headers. Plus the fact that I live in Australia, there are too many variables. I just junked by tune and I'm getting the new SSC stand alone ecu which can be adjusted by my local dyno shop.
see above. :p was a custom tune.
 

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this was a custom Gotham tune. Someone came and we spent 3 hours tuning the car at a local shop. I tried to get the A/F, but apparently the goddamn thing wasn't hooked up to read even though the tech placed the sensor in the exhaust. :wallbang:

The IAT was fine. started below 77 and went up from there. I just did one pull after I found it was f*cked. Well at least the XO point showed correct. LOL we lowered it to 5k from 5400.

This is the second tune for the 3.1, so I really don't know...I'm just going to have to try one thing after another and eliminate each until I find the culprit.

I tried to use the shop with the dynojet for the retune, but they were not available during that weekend, so I was forced to go back to the shop with the dynapack.


see above. :p was a custom tune.
I'm not sure how you have the IAT run. To get an accurate reading you would want it in the charge pipe. And you really need more data than just "started at 77* and went up."

Again you really need the other data to diagnose what is really going on. My *gut* is that you are pulling timing due to knock, IAT, CTS correction or something, but again without more data it is hard to know. Next time you go have an OBD scanner with a decent update rate scanning some of the main params: (RPM, ignition timing, IAT, CTS, MAF, if possible knock although that is not a standard PID), and of course get an AFR reading. The dyno shop should get that working, no real excuse to not have that one at the bare minimum.
 

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Plug Whisperer
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First, to reiterate, pay no attention to what the DJ does compared to the DP. I think/hope you get that by now.

On a DJ, short of some one-off glory run, the *most* you're going to see is about 265whp with SAE correction. Your estimate line is pie in the sky. Sorry.

Run SAE correction. You graphs are not showing SAE. Can make a big difference.

**Assuming your BPV isn't hanging up, which isn't all that uncommon), based on the torque curve, it looks like you're getting some VERY typical octane scaling. These ECUs are bad about that. Go to a lotus dealer or DRS and have them reset the ECU (DRS has one of our kold-fire cables), then dyno again. If there's an ECU learning issue, you'll see the torque curve smooth right out and you'll pick up any "lost" power. Likely that the scaling will come back though.

Loud blowers, old firmware, actual pinging from too much advance will all cause octane scaling with this ECU.

Phil
 

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shay2nak
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Discussion Starter #15
I'm not sure how you have the IAT run. To get an accurate reading you would want it in the charge pipe. And you really need more data than just "started at 77* and went up."

Again you really need the other data to diagnose what is really going on. My *gut* is that you are pulling timing due to knock, IAT, CTS correction or something, but again without more data it is hard to know. Next time you go have an OBD scanner with a decent update rate scanning some of the main params: (RPM, ignition timing, IAT, CTS, MAF, if possible knock although that is not a standard PID), and of course get an AFR reading. The dyno shop should get that working, no real excuse to not have that one at the bare minimum.
I have a nice OBD reader, so next drive I'll monitor the live data which updates every second or so. Unfortunately, I don't think it has a recording function, but i'll take a look.


First, to reiterate, pay no attention to what the DJ does compared to the DP. I think/hope you get that by now.

On a DJ, short of some one-off glory run, the *most* you're going to see is about 265whp with SAE correction. Your estimate line is pie in the sky. Sorry.

Run SAE correction. You graphs are not showing SAE. Can make a big difference.

**Assuming your BPV isn't hanging up, which isn't all that uncommon), based on the torque curve, it looks like you're getting some VERY typical octane scaling. These ECUs are bad about that. Go to a lotus dealer or DRS and have them reset the ECU (DRS has one of our kold-fire cables), then dyno again. If there's an ECU learning issue, you'll see the torque curve smooth right out and you'll pick up any "lost" power. Likely that the scaling will come back though.

Loud blowers, old firmware, actual pinging from too much advance will all cause octane scaling with this ECU.

Phil
For some reason when I downloaded the software from DJ's website, it displayed everything at lower numbers. That DJ plot was from my PC, the shop's scaling was on SAE and still got 255whp. Plus that was cut short, my first run was ~260whp. When you add 2lbs (3.1" from 3.2") of boost, typical gains with tune are about 15-20whp. So when you add that to 260whp, you have 280whp. I had 260whp with full 2bular exhaust, RLS IC, cup box (K&N), stock fuel sys running Charlie's tune. Not to mention this DJ reads lower.

Hey, it could be the DJ is messed up. The shop always had problems with it breaking down. I'm not going to tear the car apart until I measure again at least at one other shop.
 

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shay2nak
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Discussion Starter #16 (Edited)
re: the octane scaling....the car was tuned and learning function removed so shouldn't be that. I'm using the same fuel. I only fill up at one particular shell station.

Anyway, I'll be going back to the dynapack for a quick dyno pull this week. If the measurement is different, then I know something is going on with the ECU.

I had a chance a couple months back to buy a new ECU at a great price and like an idiot, I let it go.

Which is another thing, not sure what the "procedure" is for tuning a car and how that info is flashed into the ECU. I think whatever Charlie did to the ECU, still has it on lockdown.
 

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shay2nak
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Discussion Starter #17 (Edited)
I went back to the DP today and as I thought, the low reading I got on the DJ was THE SAME on the DP. Will post pics later. Was off by 40whp! :eek:

Nothing has changed on the car in these 3 weeks. Although I really should change the clutch, I guarantee you the ECU is bricked. The AFR was essentially the same and I tapped into the IC outlet coupler for boost which read up to 8psi right before cam XO then dropped to 6 and rose to 7.5. In fact when I look at the original tune it does follow somewhat along with the boost curve, which does mean the boost was fine at the time.

NEXT: get another ECU and reflash (not sure if the ECU I have now can be repaired.)

I'm like a drunk man at a strip club...i keep throwing money at dis bitch.
 

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.... and you still dont have ignition timing or AF info from the run. It's a lot cheaper to get that data than to just throw new parts at it.

Like is said ecu's almost never just loose their tune. It is almost always in the tune itself or an issue in the setup.
 

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shay2nak
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Discussion Starter #20
Sorry man i have been following your story, no great insight here but the above statement had me rolling. Good luck.
thanks :)

.... and you still dont have ignition timing or AF info from the run. It's a lot cheaper to get that data than to just throw new parts at it.

Like is said ecu's almost never just loose their tune. It is almost always in the tune itself or an issue in the setup.
well i've been told several times it's not the tune and I doubt it's the setup since it's been this way for about a year. The setup magically works for 2 3 hour tuning sessions, then falls apart? Strange indeed. I do have AFR, not know how to log timing with the dyno. But while driving I did see 10, 34,35,38. ECU hasn't lost the tune, but I suspect somehow the timing/cam tables got corrupted again. Charlie must have put some sort of lockdown feature in the ECU when he last tuned it. :shrug: Although, after all I've seen, it's the most logical step to suspect the ECU itself.
 
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