free hit
counters
Dyno shows up hole - Engine/Ancilliaries - The Lotus Forums - Lotus Community Partner #ForTheOwners Jump to content


IGNORED

Dyno shows up hole


Glyn Harper

Recommended Posts

So got my car back from the rolling road today, and it’s loads better! The cold start is like a normal car now (rather than really lumpy and nasty like it was) and it’s making 20bhp more than when it went in, whilst being better on fuel as well.

only issue is, a really strange hole in the power curve, as can be seen on the graphs here.

he says there is nothing in the mapping to suggest what it could be. Anyone seen this before?

the printout shows the before and after by the way which is why there are 4 curves.

 

4EDDC86D-E7AA-4B54-8817-B638EBC6F434.jpeg

Edited by Glyn Harper
Link to comment
Share on other sites


Upgrade today to remove Google ads and support TLF.
  • Replies 34
  • Created
  • Last Reply

Top Posters In This Topic

Secondary injectors not working? I'm not sure at what rpm they start operating though.

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

For forum issues, please contact one of us Moderators.

Link to comment
Share on other sites

  • Gold FFM

Possible boost control issue with the ECU?,  or boost pressure release? Turbo too small to cope with your modifications? just guessing as the power loss is so sudden.

Link to comment
Share on other sites

It's a hybrid turbo which has a larger inlet housing, but the same exhaust housing I think. I don't really feel the power loss that much to be honest, and as I nurse the car (being old) I usually change gear at about 5000rpm anyway so it's not a massive problem really. Just super odd.

Link to comment
Share on other sites

:) I'm 46 so not that old yet!

I need to change the gear linkages at the moment as the gear selection has gone horrible. I'll probably give it a bit of beans once that's done.. and I've changed the oil, filter, coolant, brake fluid, clutch fluid and spark plugs. My winter tasks. :)

Oh, and change a leaky driveshaft oil seal, and the gearbox mountings while the oil is out of the gearbox. The list of jobs never ends. Tick one off, add two more on!

Edited by Glyn Harper
Link to comment
Share on other sites

Have you any chance to monitor or look at the inlet temperature, while reving the engine on the dyno, so that you can see, if anything relating to the turbo being slow, small, big etc, ?

Normally, a too small turbo will result in loss of boost, dropping rather quickly. Have something clogged the airway as in filter, collapsed intake hose (seen that one more than once!) etc?

Do you have the ebpv? If on the car, make sure it's actually open or better take it off, incl. the throttle jack arrangement and extend tube instead.

Is your waste gate okay? Functioning okay, loosing boost? stuck? Cannot move freely? Wrongly adjusted?

Have you btw. tried to stick your fingers to the turbo vanes and tried to spin it by fingers? Easy? Oil inside the tubing from the turbo onwards?

Are your valves adjusted correctly and belt too?

Did you install one of those woosh thingies, a blow off valve, that opens way too early?

Was it always like this (well, for a long time)? Or did it show up recently? Have you done any changes lately, such as for example installing a socalled free flow airfilter such as for example k&n ? I dynoed mine with original airfilter and with the k&n and the original performed much better.

I am unsure about your engine. Which one is it? Chargecooler engine? 

So, for example, do you have the two double electronical coils as on the chargecooler engine? Do they deliver as they should?

If you run a more modern engine management, how do you then test the various sensors in that system?

I'd say that from 0-3000 rpm's it's like a normal well going car. From 3000 to 5000 rpm's it's quick. But from 5000 and up, it spins very freely and pulls hard. The car jumps forward like a tiger making a just at it's prey - an ordinary car.

Just my two pence for places to look.

In general: yes, they are supercars, so need a little attention. But the difference to many others are, that they don't cost a fortune to buy nor maintain ;) Fortunate are the ones in the know - Lotus Esprit.

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

Link to comment
Share on other sites

There's a lot of things to check there, so I'll try and eliminate things one by one. I do have a blow off valve. I wonder if that is cutting in too early? I don't have it on the rolling road now though, so won't have a proper chance to check for a while.

Same as the MAP values. I don't have those unfortunately. But I'll try some of the things mentioned and see if I can spot anything.

Thanks.

Link to comment
Share on other sites

  • Gold FFM

Just looking at the graphs, the issue is a lot worse with the new map compared to the old. You're now making more power at 4800rpm than at 6800rpm, as you should. If the reading at 4800 is correct, that's very impressive! But maybe it has to do with the measurement on the dyno, giving too high a reading at lower rpm and too low at higher rpm?

As Jacques says, normally you'll get a second kick in the back around 5000rpm, with the secondaries opening. With this graph, you'd actually lose power going above 5000rpm, that can't be normal.

I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

Link to comment
Share on other sites

I don't have secondaries as I have an aftermarket ECU which just drives 4 injectors.

He did say it could be something with the rollers, maybe if a wheel were out of balance it could affect the readings.

It drives and feels fine though and you don't feel a massive power drop or anything. It's just a bit off to see that on the graphs.

Link to comment
Share on other sites

  • Gold FFM

I read how you don't have secondary injectors, but larger primaries. Those should be able to provide the same amount of fuel, so you should still feel an increase in power at higher rpm. Let's hope it's just the dyno-measurement and your feeling when driving the car is correct. ;-)

I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

Link to comment
Share on other sites

As Filip says, and I mentioned, you should be able to feel a very noticable power increase at near 5000 rpm.

So my question is this: do you when driving on the road, feel a very free reving engine and a very noticable shove in the a..e from 5000 an dup to at least 6800?

As Travis says, old tires can slip, but here you had two rolls made on the dyno, and it would be a bit strange, if the tester did not notice anything on both occations? When I have watched very powerfull cars being dynoed at the place I use, I've seen tirespin, and it's noticable both to the tester and the spectator.

Idea: Use another dyno to investigate if there's anything with the tester, the procedure, the dyno, the tires etc. That's easy to verify.

Does it slip easily with the rear tires, when driving?

Just my dumb question: does your clutch work normally? No slip, no issues?

You can get a cheap heatprobe/tester and stick the probe to the chargecooler surface, and monitor the temp when driving and when pushing real hard.

On a standard setup on the chargecooler engine, the turbo is a bit small for prolonged performance, and therefore it heats up the air quickly, so that the chargecooler cannot bring it down efficiently and power drops off. Something like that. One may feel this after some hard accelerations and/or prolonged rpm's - then heat drops as boost drops.

Can you feel this on your car? That's easy to verify too.

Bigger turbo's can compress more air while being cool(-er), so power is sustained better and longer.

How is your car on this?

A friend of mine bought an SE, and as we drove home, he felt the car running very well, nice idle, nice power, nice raise in power etc. But not fast. Upon inspection, he found the impellor to be loose from it's center, so in effect not using the chargecooler system's circulation functionality. After he renewed the impellor with a new black original one, he test drove the car, and it was MUCH faster ;) Test also for example driving a similar Esprit.

That is easy to verify as well.

How old is the coolant in both systems btw? Or one common plastic bottle?

When was your last known state of perfect running and being fast? What was touched since then?

As you said that you have a blow off valve, where is this installed? Near the belts or near the turbo?

If the first, just take it off, reconnect the little hose and install the standard silicone tube without the extra port. So you can easily eliminate that point. Or find that your bov is a pos. Anyway, they are not all working as expected and calibrated to your car. 

Regarding the chargecooler and air temp, when I installed a Sport300 turbo, which is bigger than the SE one, I quickly noticed the difference in air temp even by just touching the outer top surface with my hand, and it was a fair bit cooler.

When after driving in anger your car, id your chargecooler hot, cold or ? (as in jump out and touch immediately before heat soak is too much). Or measure it with an infra red gauge tool from halfrauds or elsewhere (cheap china thingy).

What is the state of the two rubber mount of your chargecooler? Are they perfectly working, or are the broken, flattened or? 

New ones may raise the chargecooler itself ever so slightly, and visually inspect a clear air gap between the cam tower and the chargecooler. Measure with old rubber mounts and with new ones. (you can also insert a sticky heatshield to the underside of the chargecooler - and sides, but that's not a remedy, just an improvement).

Let's hear what you find, before Winter and hibernation time sets in ;) You never know in this strange weather day and age.

Btw, sorry for my dumb question, but have you any verification that your fuel pump can actually supply the fuel needed at high rpm's? I know your setup is not standard, but it would be very interesting to know, if the fuelpressure is correct. For example in Service Notes, I think there is a procedure for verifying this, by coupling a hose and gauge to the schraeder valve at the end of the fuel rail, on the fuel pressure regulator (fpr) ?

Inspect the fpr (if you have one still) little vacuum hose and connector(-s).It will become split at some point.

And if you still maintain the Lotus fuel pressure regulator, does it work, or is it collapsed inside? (as in letting too much fuel go to the return line, back to the tank).Can you swap it for a similar one from a friend local to you?

As an alternative, I can borrow you my set of fpr regulator which is adjustable and with a gauge. It's from Ramspott und Brandt in germany. But if will also be fairly easy to make a kit from parts from say fleabay or motorpart shops. Give me a shout if you want to borrow it, and I'll ship it over to you. I may of course be all wrong because your car has the modern set up, so these parts may be omitted? In that case, just don't mind my comments ;)

Higher power needs more pressure, hence my question. If you say never beat the living daylights out of your car (as in 5000 rpm and up), maybe you have never noticed that the fuel supply is too low for high rpm's? Just my guesswork.

Yes, the engine will normally make higher HP's when driving on the road because of sufficient cooling and better ram air.

Btw what was the factor and the humidity and the air pressure that day on the dyno? Would normally be stated on the print out/file. Make sure you have the same values for future use, so they can be compared. The dyno program can normally be adjusted for that and even tell you several set up's to compare. Honest dyno testers are always conservative. Just a footnote.

And another fooltnote. As my native language is not English, I don't understand the sentence that something could be wrong with the wheels on the rollers? Did he mean problems with the dyno rollers itself, or your car? Normally, a tester cannot repair these setups themselves, but need a tech guy from the dyno manufacturer company. I've seen it and it takes a full day to calibrate it.

Anyway, sorry for all my questions.

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

Link to comment
Share on other sites

It’s using separate coolant for the engine than for the chargecooler.

I am wondering if the wastegste spring is sloppy, allowing a degree of overboost?

I think I remember seeing this before, possibly on my Escort RS Turbo days, where to much boost would effectively ‘bounce’ the wastegste actuator briefly.

The turner said fuelling was fine looking at the lambda values, so that rules out a few things like fuel pressure.. so I’m wondering about this bouncing effect now.

Link to comment
Share on other sites

I did a drive tonight and checked the chargecooler... roasting hot!! :(

im using an electric pump so I shorted the relay I have for it to make it permanently on, and it does sound like it’s spinning ok. But no water from the ‘tell tale’ bleed pipe.

so either it’s impeller is broken up (its lasted about 16 years!!) or I just need to bleed the system. Hopefully it’s the latter.

I’ll bleed it tomorrow and see if that helps.

would that cause the dip in power possibly?

Link to comment
Share on other sites

I would expect the chargecooler to affect the power throughout the entire curve. Certainly when boost starts at lower than where you are seeing the hole? Aren't the secondary injectors there to stop the engine going lean at high rpm? How does your ECU compensate for that by only using 4 injectors? I presume your primaries aren't standard?

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

For forum issues, please contact one of us Moderators.

Link to comment
Share on other sites

plotting the MAP and IAT with the power curve would be very revealing.  your ECU can data log.  likely you found a culprit with the air temp rise.  take it back and tell the tuner to log the data during another dyno run if he didnt already

chris

90SE

just because I don't CARE doesn't mean I don't UNDERDSTAND

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.



Upgrade today to remove Google ads and support TLF.


×
×
  • Create New...