"Big Turbo" modification

[Atle]

Hi all,

Bought my 1991-built Esprit SE this summer from Switzerland, it was in very good condition. The dealer told me they knew of no modifications apart from the quad Remus exhaust, which is apparent.

The car certificate told me the previous owner's name and it turns out he still has his LEW page online - albeit with one "red spot status".

On his page I can read the car has had 2 significant modifications, one is the exhaust which is easily confirmed; the other he says is the "big turbo". So for a dummy like me, what in the tarnation does this mean? I can always e-mail the previous owner but sort of hesitate to that if anyone here can explain...

I have tried the turbo mod pages on LEW but can not make much out of it, and since it is simply referred to as "big turbo" this seems to be a well known mod but I miss out.

Do I have more HP than the specified 264?

Edited January 11, 2008 by Atle

[wiseraven]

Without knowing which turbo, it's impossible to say. Even if you do find out, the Turbo Options thread demonstrated that hard facts about turbo performance are sadly lacking. If you haven't read it already, I reccommend you do so, if only to make it clear just how little clarity there is on the subject.

Bigger does not necessarily mean better - the rule of thumb is that a bigger turbo will have more power, at the expense of more lag. However, the people selling the turbos claim that their better bearings counteract the lag problem (although no hard evidence was forthcoming).

Even if increased lag is avoided, you may not actually realise the potential power increase of the bigger turbo if your inlet and/or exhaust are too restrictive. If you're running with the stock chip, the ECU will be limiting the boost generated to that of the stock turbo, so except possibly at the higher end of the rev range you won't notice any increase in power. If you're increasing the boost, you also need to ensure that the fuel delivery (i.e. injectors) are up to the task, otherwise you risk running too lean. The stock injectors are generally regarded as being pretty poor, so if you have these, they may easily be limiting your power.

Some turbo sellers rate their turbos using phrases like "for engines up to 400 bhp". What they really mean is that the turbo will flow enough air to feed an engine producing this much power, based on thermodynamics - essentially, you have to burn a certain amount of fuel in a certain amount of time to achieve a certain power output, and to burn that amount of fuel requires a certain amount of air. However, obtaining the figure quoted assumes that the entire engine is tuned to maximise the use of the turbo. It also tells you nothing about how the turbo delivers this power - it may only produce it in high displacement, low boost configurations, rather than small displacement, high boost. You need to consider the system as a whole to get the most out of the turbo, and the wrong one for your system can actually be worse.

The first step for you in evaluating what you've got would be to find out from the previous owner exactly which turbo is fitted and, if you can, find out from the supplier what its characteristics are. Then get a freescan trace to find out how much boost you are actually getting, how soon you get it, and for how long it is sustained (one suggestion is that the stock turbo runs out of puff at the end of the rev range)

Sorry I can't be more constructive,

Phil

[Atle]

Thanks Phil, for exhaustive (literally) explanation. I understand what you mean, engineering wise. Find it hard to see, visually checking the engine, that much has been modified at all - from the original. Will have a closer look when the sun comes back to this country. I may eventually contact the previous owner and ask - and of course the freescan trace at earliest convenience. Interesting to know.

Gotta run!

[Riddlemr2]

Post some pictures of the turbo - we'll be able to at least get a good idea if it is the stock turbo housing or not.

[Atle]

Good idea!

Sure will do, open the garage tomorrow.

[Atle]

Hi again,

Been some time but finally took a photo of the turbo assembly on my SE.

So can anybody enlighten me if this is a "big turbo" modification or the one that came off the production line in 1991..?

[Htown]

Take a closer pic of that tag just behind the coolant line, or read the serial # of it....

[Qavion]

Looks identical to the one on my 89 SE... so the mods must be internal.

I have these numbers on mine:

TBO373

5E0142A

485133 2

A919(or G?)E69591

Anything there look similar?

WC Engineering in the USA do internal modifications without any external changes (direct swap)... Maybe this is what a "big turbo" is? Anyway.. it's interesting reading...

http://www.wcengineering.com/esprit/turbo.html

Cheers.

Ian

[sanj]

Looks identical to the one on my 89 SE... so the mods must be internal.

I have these numbers on mine:

TBO373

5E0142A

485133 2

A919(or G?)E69591

A910E6959 is the Lotus part number for the standard SE/S4 turbocharger.

[rocket63]

Looks like an OE Turbo to me. maybe the internals are different, although this would not necessarily flow any more air if the aperture diameter is the same?

[Atle]

Thanks so far guys, I have been away again unable to check but will try tomorrow....

[TurboSE-SLO]

Hi all,

Bought my 1991-built Esprit SE this summer from Switzerland, it was in very good condition. The dealer told me they knew of no modifications apart from the quad Remus exhaust, which is apparent.

The car certificate told me the previous owner's name and it turns out he still has his LEW page online - albeit with one "red spot status".

On his page I can read the car has had 2 significant modifications, one is the exhaust which is easily confirmed; the other he says is the "big turbo". So for a dummy like me, what in the tarnation does this mean? I can always e-mail the previous owner but sort of hesitate to that if anyone here can explain...

I have tried the turbo mod pages on LEW but can not make much out of it, and since it is simply referred to as "big turbo" this seems to be a well known mod but I miss out.

Do I have more HP than the specified 264?

Hi,

What boost are you running? More than 0,85 bar? When overboosting, how much is it? More than 1 bar? How long is your overboost period?

Do you have a Freescan? If yes, send me a file.

It's almost impossble to see from the picture if turbo is modified or not. Modified turbos have bigger compressor wheels and usually 360deg. bearrings inside.

BYE, B

[Atle]

Hi all,

So finally got around to climbing into the boot with a flashlight, not easy to read the numbers with my eyesight even with reading glasses but here is what I think I read:

A 91016959

465133-2

TK01437

110373

I think....

So, according to Qavion I may have misread a "1" for an E in the first serial number A910E6959 thus the turbo is original?

Borut, thanks for tip, must admit I have had the car for such a short time I have had to keep my eye and energy frenetically on the traffic...the boost indicator is still an uncharted item onboard but now that you have put me on it I will check. Weather here is winter-spring-winter-spring every other week so driving is somewhat fragmented...

Will get back - AHA just saw on LEW what the "Freescan" is. Yeah, gotta get this kit.

Edited March 16, 2008 by Atle

[rydning]

Hi Atle.

Your turbo look like a brand new stock one.

Very good to see other Norwegians going for this nice car.

[Atle]

Hi mate,

Nice winter we have had! Instead of moth-balling the car in expensive winter lay-up I have been driving on dry and ice-free roads every weekend since mid-January!

Up to today, alarm immobilized me see separate thread. I am in panic!

I also am now pretty sure the turbo is "as built" stock...and looks brand new, in fact the car looks brand new all over (or only a few years old). Even well seasoned petrol-heads are amazed.

See you around?

[kyliesmith.com]

Lovely car Atle, it does look really clean in there and appears the PO did look after it. Enjoy !!

Did you end up emailing the PO? I would for peace of mind knowing whats else is in there.

[Atle]

Hi Kylie, thanks for your commendation.

Yes, it struck me this afternoon that I could e-mail the PO. Nothing to loose, considering the way both he and the one before that took care of the Esprit.

I have a psychotic disfunction to block out the past - maybe from bad experience but this is after all just a car...