0.5lb of boost is that normal

[simonf 12]

Just a quiky for any S3 Turbo owner (or anybody else for that matter!) my standard S3 Turbo is running at only 0.5lb boost on full chat, and that seems a little low to me (only as such that if the guage goes round to 1lb i reckon i should be kicking 0.75lb) i am not after warp factor 4 but just need it to be running correctly.

anybody else boosting the same or is mine low.

PS The car goes fairly well - so it might ne that the guage is reading low of course!!!

[Simon350S 192]

8psi is standard on our cars mate (from LEW)...... thats about 0.55 bar i think...

8 pound/square inch = 0.551 580 582 bar

So your about right.... maybe slightly under but I doubt it, probably just the angle you look at the guage....

Simon

Edited September 11, 2007 by Simon350S

[dodgy 26]

yes Simon, i agree with, er , Simon

mine boosts to .65 bar for a short time, and then settles to .55 bar.

anything above and sustained could blow the pistons with the Low Compression engine.

It maybe a fraction low, but it is better than overboost

[cly_mitchell 1]

Damn Dave, I cannot believe nobody has bought your car!!! I thought it would sell quick. With the people comming on the sight asking what kind of Esprit to buy, WTF? It don't get much better than that.

Bumfuseled?

Clay

[Buddsy 1,656]

Simon, Ive seen something on this somewhere but cant find it!! doh. Im sure I read an article that Lotus had found most people had their wastegate valves set up wrong or too much play/wear etc. I think it was the wastegate valve but could be mistaken. The article went on to show how you can use a hand pump & pressure gauge to check the valve only releases the excess pressure when over the correct set psi, I think 8.5. I could be talking b******ks but Im sure I didnt dream it and read something along those lines. Maybe Brian would be the man to ask at the next meeting.

Hope I havent confused the issue!!

[dodgy 26]

the waste-gates on the 'G' cars were a separate unit, not like the adjustable ones on the later cars, so the waste gate was set at the manufacturers (of the wastegate), they can be adjusted by adding washers to the inside, but this can be 'hit and miss'.

I brought the Last Waste-gate available from the factory, this is set to 0.5 bar !

As for the car not selling Clay i have not really been pushing it have i? , i should, but its a 'do not really want to let go' situation She has been so good to me, and i do not even have to think or worry about taking her on a 300mile journey.

It is going to be such a sad day that must be,as i cannot afford to have 2 Esprit's at the same time

i am having trouble pushing myself to sell

Dodgy

Edited September 12, 2007 by Dodgy

[Buddsy 1,656]

Well looks like I was talking rot after all lol Thanks for bringing some clarity Dodgy

[Brandt 0]

My '83 Esprit is showing 12PSI on the Boost Guage.

I've read that sometimes the wastegate simply needs to be cleaned. Is it possible to remove the wastegate without the section of the exhaust that it fits into?

[dodgy 26]

yes it can be removed, but chances are the studs are rusted up tight, so soak them well in a releasing agent and let it penertrate overnight if possible.

[WayneB 2]

My Esprits standard Garrett wastegate was set for 7.5 psi from the factory (marked tag on side of unit)

If you suspect your car is underboosting, it might be a good idea to remove the wastegate and check to see that the cast iron wastegate adapter valveseat isnt cracked and allowing exhaust gasses to bypass the turbo via the wastegate exhaust pipe.

One big give away to this problem is the boost takes longer to build up than it used to.

Overboosting is usually caused by a jammed wastegate actuator valve (free off with penetrating oil) or a holed wastegate diaphragm(replace If available). The wastegate must be actuated regularly to avoid siezing (by driving the car using the boost)

It could be of course that someone has fiddled with the wategate to get it to allow 12psi (spacer, stiffer actating spring, air bleed) in which case you should try and get it down to at least 9psi (unless your engine has forged pistons fitted,and or intercooler/chargecooler) so it will last.

Edited October 22, 2007 by WayneB

[bigsi 0]

i noticed today that mine boosts upto 0.75 on the dial almost 3/4 the way round and then it does the phshhhh thing but its not a nice sound at all its rather raspy and grating, im going to check my wastegate tomorrow, where would i find the setting mark on my wastegate wayne? also if it is stuck would the one below the fuel pressure regulator kick in then?

[Kimbers 1,907]

Ahhh the old Wastegate diaphram! Source of many a hearache and totally and utterly out of stock worldwide and likely to stay that way!

[andydclements 813]

Ahhh the old Wastegate diaphram! Source of many a hearache and totally and utterly out of stock worldwide and likely to stay that way!

Oi, you, sitting in the warmth, get outside and fit your new brakes.

Andy

[Bibs 11,657]

Engineering have found a manufacturer of these in China and I'm sure they're on the way soon!

[WayneB 2]

i noticed today that mine boosts upto 0.75 on the dial almost 3/4 the way round and then it does the phshhhh thing but its not a nice sound at all its rather raspy and grating, im going to check my wastegate tomorrow, where would i find the setting mark on my wastegate wayne? also if it is stuck would the one below the fuel pressure regulator kick in then?

Simon, there is a small plate rivetted on to the side of the wastegate with the factory set wastegate opening pressure stamped on it.

The phshhhh noise is the blow off valve opening (the one under your fuel pressure regulator), which usually opens around 12 to 15 psi, and is designed to instantly vent excess boost pressure to the atmosphere when the throttle butterflys are closed.

Sounds like your wastegate may have stuck.

[bigsi 0]

heres the plate on the side of the wastegate wayne, what do you think? is mine ok going to 0.75 on the dial then? as it states 7psi

[Simon350S 192]

EEErrrrrrrrrrr.......... NO.....!!!!

Thats 7psi dude......

Your guage reads Bar....

0.75bar = 10.87783 psi....!!!

Thats.... err.... too high.....!!!

Your wastegate was freely moving when it was rebuilt and the valve seat in the wastegate adaptor manifold thigy is a little cracked, as most of them are......

Yes check to make sure that your wastegate is free to move... could be the diagpram has a small hole which is alowing a cretain amount of pressure to leak causing a higher boost....

Could also be that the boost tube from the turbo to the wastegate hasn't sealed properly and your venting little pressure from there giving you a higher boost level.....

The fitting was replaced in your wastegate..... for.... ermm..... mine....!!! as yours was damaged so it maybe that when that was refitted it hasn't sealed properly..... don't know if any sealing tape or paste was used as I didn't do it.....

Lots for you to be getting on with......

Add it to your list of other things mate and you'll be busy for a while....

Simon

[bigsi 0]

well i opened up the wategate before it got dark and it moved fine, and theres no holes etc in it , what happens is when i put my right clog down the boost guage climes to 0.75 sometimes and then drops. so whats going on then because i havent got a bloody clue.

what fitting was replaced?? when i stripped my wastegate the cup, spring, backing plate, diaphram, top plate, and valve stem were fine, so the only thing it needed were new upper and lower gaskets to stop the diaphram sticking to the metal cups.

Edited October 24, 2007 by bigsi

[Simon350S 192]

The brass fitting on the outside of the wastegate to which the small stainless pressure tube from the turbo is fitted.... think it was the wastegate end, if not it was the turbo end as in storage it must have got damaged.... so it was knicked off mine when I was in Oxford I think... LOL

Being that it is a mechanical system their is a good chance that you get a little overswing of pressure before the valve opens and stabilises the pressure....

If it hits 0.75 and then drops back to normal then I'd guess thats normal.....

With your new exhaust system the pick up in boost (not max boost) may have increased significantly, the knock on effect will be an increased time to regulate the boost.....

Just my 2p.....

Simon

[Brandt 0]

I finaly got the wastegate out; well parte of it. The nusts came lose fine, but it seems there is some sort of exhaust sealant on the screw treads on the holes and th cast iron bit won't budge. But the diaphram housing is off and there is a nice big rear in the diaphram.

So i'll ge a diaphram from SJ. I was just wondering if Garrett doesn't supply the diaphram?

Is it normal for rust scale to be present in the steel part of the diaphram camber? There is losts of lose rust scale present in my unit, and I think the rust scale could have helped with that hole in the diaphram.

Is there an easy way to check the wastegate spring tension? Something in the line of pressing down on the spring by hand whilst the spring is resting on a scale, whilst check the scale reading? What should the scale read if the spring is compressed by say 1/2 inch?

[BC007 6]

Mine reaches just 0.5 too!

Brendan

[bigsi 0]

i dont know how to tell you this but there are no diaphrams available, period! there may be some in the pipeline new fbeing made in china we are not 100% sure yet.

[PER 0]

i dont know how to tell you this but there are no diaphrams available, period! there may be some in the pipeline new fbeing made in china we are not 100% sure yet.

It seem like Sj has got hold of some of these diaphrams. If you take a look at the news and offers page on his site.

"We now have the waistgate diaprams in stock for the early Esprits.

[Esprit Aviation 2]

That's why I changed my turbo over to the integral wastegate type. $170.00 USD just for a piece of rubber covered cloth...I don't think so!!

[bigsi 0]

for not much more you can get the turbo upgrade kit from gary kemp, by the time you pay that plus postage and vat you may as well.