Problem with Turbo? Sluggish 0-60.

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Problem with Turbo? Sluggish 0-60.

Postby basher » Wed 04.07.2018, 11:52

I checked the 0-60 on the car recently and it was significantly down on what it should be.
For a while now I haven't had the throw back in your seat turbo effect and I have got a spare Turbo refurbed as I can only think that is the problem. Before I change it, I have some questions, the last thing I want to do is to go through all that and it not be the problem if I can avoid it.

1.If the turbo isn't working, will you get boost building and showing on the gauge?
The car will build up boost as normal if I floor it but I don't shoot off down the road, I'm not getting the turbo effect. It will rise to 0.5 bar and not go any further and will not over-boost and cut out if I continue to floor it as it used too. In some circumstances it will boost beyond 0.5 to maximum and still not overboost and Imp still accelerating like a n/a. It feels like there is some sort of hesitation, its on the verge of putting points on my licence but there is some sort of blockage that is preventing it.
2. Can the turbo spin, build up pressure, but then not deliver it to the engine somehow- could I have leak there?
3. If the dump valve was a problem surely the boost wouldn't build in the first instance as that's the point of it isn't it?

The car has a dump valve which was on there when I got it and you can hear the pressure being expelled when I back off. I could get rid of this if I thought it had a problem. It also had an aftermarket air filter which I replaced with the standard air filter which was probably around the time that I lost my zip. I have taken the pipe off the filter and let the car have all the air it can eat as a test and it was a little bit more zesty and definitely more audible but it didn't solve the problem.
A while back we had to free off the waste gate as that had stuck. We also checked the pressure using the inner tube on the turbo and have found numerous little leaks that we have fixed, so it is airtight but it has made no difference.
The engine is old and I assuming I've lost a few horses along the way but Im thinking that shouldn't effect the boost effect? I would still get a kick in acceleration even if the engine was on its way out.
She will happily cruise along at 70, 80+ all day long and the engine runs smoothly.

Any help gratefully received.
Last edited by basher on Wed 04.07.2018, 12:34, edited 1 time in total.
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Re: Problem with Turbo? Sluggish 0-60.

Postby Giniw » Wed 04.07.2018, 12:17

basher wrote:1.If the turbo isn't working, will you get boost building and showing on the gauge?
No.
It will rise to five bar and not go any further and will not over-boost and cut out if I continue to floor it as it used too.
Are you sure you are looking at the boost gauge? 5 bars of boost is *a bit* suspicious and very much looks like the oil pressure gauge :-D

2. Can the turbo spin, build up pressure, but then not deliver it to the engine somehow- could I have leak there?

There could be a leak and as a result the turbo would struggle build the pressure up, but as long as there is the pressure you should have the turbo effect. But the turbo would spin faster than nominal and that could wear it. So a leak should be fixed (and it would affect the idling too of course).

The engine is old and I assuming I've lost a few horses along the way
Have you checked the compressions?

Have you made an ElanScan log?
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Re: Problem with Turbo? Sluggish 0-60.

Postby basher » Wed 04.07.2018, 12:40

Sorry, moron moment, should have said 0.5 rather than 5.
However, I'm doubting myself now and will have to take it around the block to ensure that Im not talking total cobblers. - (Yes, it reads slightly over the 0.5 level)

There could be a leak and as a result the turbo would struggle build the pressure up, but as long as there is the pressure you should have the turbo effect. But the turbo would spin faster than nominal and that could wear it. So a leak should be fixed (and it would affect the idling too of course). - I'm guessing that would still be picked up by the pressure test with the inner tune though?

Have you checked the compressions?- Nope, but that's a good suggestion.

Have you made an ElanScan log?- Nope, Ive never done that.
Last edited by basher on Wed 04.07.2018, 12:57, edited 1 time in total.
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Re: Problem with Turbo? Sluggish 0-60.

Postby rip » Wed 04.07.2018, 12:53

Ignition timing made a huge difference with mine. I assume the pulley must be on correctly but the timing mark is very small & easy to get confused with a missing piece of paint.
Anyway, I did it by stopwatch, advancing it bit by bit & doing a test 30-70 in 3rd on the same stretch of quiet dual carriageway.
I also used Elanscan to look for knock being detected.
I ended up advancing it by 16 degrees from where it was....but was what seemed to be the timing mark actually the timing mark.

If you mark the position of the CAS before you start then you can simply move it back if anything goes wrong.
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Re: Problem with Turbo? Sluggish 0-60.

Postby Bern » Wed 04.07.2018, 17:15

rip wrote:Ignition timing made a huge difference with mine. I assume the pulley must be on correctly but the timing mark is very small & easy to get confused with a missing piece of paint.
Anyway, I did it by stopwatch, advancing it bit by bit & doing a test 30-70 in 3rd on the same stretch of quiet dual carriageway.
I also used Elanscan to look for knock being detected.
I ended up advancing it by 16 degrees from where it was....but was what seemed to be the timing mark actually the timing mark.

If you mark the position of the CAS before you start then you can simply move it back if anything goes wrong.


I'll second that, if ever mine starts to lose it's edge then re-doing the timing always sorts it.

I seem to have to do it so often that I've put in a switch to save shorting the pins in the diagnostic socket.
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Re: Problem with Turbo? Sluggish 0-60.

Postby Rambo » Wed 04.07.2018, 18:17

Basher - before you start mucking around, check that your wastegate/actuator is functioning as intended. You may wel, find its stuck or sticky if you haven't used the car much recently

An easy and simple test :x
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Re: Problem with Turbo? Sluggish 0-60.

Postby Rambo » Wed 04.07.2018, 18:23

@ Bern. Seems very odd that you have to check your timing so regularly ??? My cars never need it from one service to the next :smt017
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Re: Problem with Turbo? Sluggish 0-60.

Postby Bern » Thu 05.07.2018, 08:30

Yeah, it is odd! I'm not sure why it would go out, there's no mechanical points or anything like that! I probably do it every couple of months, and it's not like I drive it that much!
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Re: Problem with Turbo? Sluggish 0-60.

Postby rip » Thu 05.07.2018, 08:35

Bern wrote:Yeah, it is odd! I'm not sure why it would go out, there's no mechanical points or anything like that! I probably do it every couple of months, and it's not like I drive it that much!


I think it was Paul Watkins who mentioned that he adjusted his regularly too. He has now sold it on.

Our Elans do seem to be very individual don't they? I can understand the hand built parts but you would expect the engines & gearboxes to be consistent with each other.
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Re: Problem with Turbo? Sluggish 0-60.

Postby elaverick » Thu 05.07.2018, 09:16

basher wrote:It will rise to 0.5 bar and not go any further and will not over-boost and cut out if I continue to floor it as it used too. In some circumstances it will boost beyond 0.5 to maximum and still not overboost and Imp still accelerating like a n/a.


Is it possible that rather than a wastegate problem on this turbo, you actually had an issue on the old car? I don't think overboost and cutting out is meant to happen at any point is it? When I had my fuel injectors replaced, the company doing the work spotted the wastegate was sticking and freed it off, and at that point the car lost a bit of urgency about it. I'm wondering if you'd got used to a broken vehicle and are now experiencing them as they're meant to be...
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Re: Problem with Turbo? Sluggish 0-60.

Postby basher » Thu 05.07.2018, 10:15

I guess in normal circumstances you shouldn't have overboost and cut out, only if you push it too hard, its a safety measure.
My point is, that the car is not performing as it should and even when I do things that really should result in overboost and cut out, that doesn't seem to happen.

Thanks for the advice everyone.
The wastegate moves and appears to be free enough, but I will clean it up all the same to cover all bases.
The timing was set up a while back as it kept stalling when I came up to junctions etc, that was thought to be part of the problem. That issue no longer happens, but we have found since from the pressure test that the intercooler was leaking quite badly along with some other little issues.
Could those problems have effected the tickover to make it stall, rather than timing problems and hence put it out of adjustment now?
I've no real clue how it all works just throwing ideas out.
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Re: Problem with Turbo? Sluggish 0-60.

Postby basher » Sun 15.07.2018, 08:05

Just to follow up on this.
We checked the timing using the wikilec guide and it was significantly retarded. This is disappointing as it was given to a specialist not that long ago to fix the fact that it kept stalling on low revs and they claim to have checked that properly. They also missed the fact that the boost pressure was a problem because the inter cooler had a severe leak and we had another couple of less critical leaks. Anyway, timing was corrected and the tickover eased back as it was a little fast.

Still, performance is a lot improved and she is definitely far more spritely than she was, I will have to check 0-60 again.
Thanks for advice all.
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Re: Problem with Turbo? Sluggish 0-60.

Postby Fredjohn » Sun 15.07.2018, 11:41

In normal circumstances you should not get over boost. The waste gate is there to prevent boost going beyond 0.65. The cut out will prevent over revving.

If you are getting over boost, either the waste gate is stuck closed, or it's port is too small to cope with the flow. The latter generally only happens when you have chipped the ECU to raise maximum permitted boost. Hence the need to bore out the port as many chipped owners do!

If your car is std and you feel it is under performing, check timing again, check for induction leaks again, especially loose vacuum hoses from back of engine, any leak in the induction system will affect tickover. Also run an elanscan, that will give you a fair amount of data on boost levels, induction leaks etc etc

The dump valve will affect boost if it is leaking as mine was. If you can remove it and ensure induction hoses are then properly sealed, that will help diagnosis. I bought a replacement rubber seal kit for the dump valve which solved that issue. The dump valve only releases excess induction pressure (not exhaust pressure) on lift off, it should do nothing at all other times.
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