Glowing Red Exhaust Manifold & Hesitation Around 6000 RPM

[dawn]

Last night after a drive of 1 hour highway driving between speeds of 60 - 130 mph where most of the time engine was boosting between quarter and full boost according to the boost gauge when I stop for refuelling I noticed that the exhaust manifold was glowing red. Should I consider this normal as the engine was not on full boost during the journey?

Also sometimes there is a hesitation in the engine around 6000 rpm where engine struggles and the tachometer fluctuate between 5000 and 6000 rpm and after this fluctuation revs to 7000 rpm.

Should I consider the red hot manifold as a problem and what could be the reason for the hesitation around 6000 rpm?

By the way the car is a carbureted 89 Lotus Esprit Turbo.

[Advantage]

Glowing red? Perfectly normal.

[Jonathan]

Yeah, I'm not happy unless I come back from a run without the manifold on fire !

On a causal run perhaps not but once the car's got hot - if you peg it the manifold should show signs of glowage.

[waynef]

Yes perfectly normal the glowing red

As for hesitation remember your driving a Turbo car.

You don't need to be max boosting all the time keep the car in its peak torque range and you'll get better performance. On the track I noticed this too, on the windy bits car is awesome on the straights runs out of puff, boost and stumbles between 6-7400rpm. Yet on normal driving conditions even going to the redline never has an issue.

There are loads of posts on here about boost, turbo set up etc and the reason why the Esprit runs out of boost at sustained high speed, its only a 2.2 remember.

Anyhow enjoy her but i'd definately recommend keeping her in the optimum torque range. You will find power tails off in mid to high 6k revs.

Waynef

[Mark Blanchard]

When you've finished driving, let the car tick over for a few minutes before you turn the engine off, to let the manifold cool down slowly. It'll preserve the life of the manifold (and the engine).

[dawn]

After getting your approval about the glowing red manifold, I again headed for the highway and here are the glowing results for tonight

[rogerch]

[Bibs]

Very nice

PS I hope the engine was still ticking over when you took them!

[Tony94S4]

yep make sure that engine is running till that glow goes a way,

if not wont last to long

[EspritMiltonKeynes]

@GKP: Is that a Lotus 910 turbo engine? It looks like a straight-5?!? Or am I just going mad....

[Bibs]

Mad.

HTH.

[dawn]

What are your thoughts about installing a pyrometer or even a wideband in order to have an idea about the temperatures and to control whats going on in the engine?

[Bibs]

It's running within it's parameters, I don't think there's any need.

[dawn]

So is this a correct assumption? Since its carbureted its ability to adjust itself for different conditions is limited compared to a fuel injected Esprit (thats why I think that it needs a pyrometer more than the later ones). But since its max boost levels are lower than the injected engines, everything is under control.

So I can keep on taking glowing turbo pictures. B)

[rogerch]

Speaking of cooling down, it seems I'm usually on my way home when I tread on it, I have always considered that the last bit of any trip through 50-60 k zones and less, then manoeuvring into the drive and putting it away was sufficient cool down. You can feel the heat coming out of the rear nearside wheel arch but the turbo is not glowing.

Is that enough of a cool down?

[Jonathan]

Cool down - lay off the boost 3-4mins before you reach the end of the journey ESPECIALLY if you have been nailing it, high gears, low boost / rpm.

Exhaust temp is proportional to your right pedal.

Then let it idle for 2-3 mintues.

You can get turbo timers which keep the ignition on but allow you to lock the car etc but I just sit there with it, unpack / have a stretch etc. Prob is I have thought about leaving it on is what happens if you switch on just as the fans come into play ? heat soak will creep in and the engine could get past the safe line, just something to think about and which is why I always let it cool off 5 mins before getting to my destination, to speed the cool down time up.

If I get stuck in traffic and so on I dont bother much past a minute or so, it's only a major concern if you have been giving it the clout

[renckensj2]

However my exhaust manifold is also glowing, certainly after a fast ride, I am very concerned about it because I suppose that the outlet valves are also glowing and that is not good of course. One has to make sure that the ignition advance is correct because this is a very important parameter for the exhaust temperature. If the gas-air mixture is still burning when the outlet valves are open then this glowing of the exhaust takes place. At high rpm of the engine, there is less time for a complete combustion and for this reason the ignition advance must become higher in order to get more time for complete burning. If this advance is too short the valves will become too hot. I want to believe that an Esprit can have a little bit more then a normal car but there are no miracles and one should not underestimate this glowing.

Regards

Jos

[Paul93Lotus]

Also make sure you don't have a clogged muffler. Clogged catalytic converters can also cause that, as well as running very lean.

It might just be the exposure of the picture....but it looks a little brighter glow than what is typical.