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1983 turbo wastegate


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what do you mean by the inlet size?

the OE wastegate label on a new gate assy says : wastegate assembly - 32mm

with a control pressure of 6.5 psi as standard , this should then be adjusted (i think) to 8.5 psi (0.65bar)when fitted.

Dodgy

Лотос - для тех которые знают разницу

ENIGMA for those who are paranoid or download one :)

 

 

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what do you mean by the inlet size?

the OE wastegate label on a new gate assy says : wastegate assembly - 32mm

with a control pressure of 6.5 psi as standard , this should then be adjusted (i think) to 8.5 psi (0.65bar)when fitted.

Dodgy

dave when you say adjusted what do you mean?

i have to rebuild my assembly aftser stripping it down for cleaning and deoxidisation and to check the diaphram.

theres nothing i have to do apart from this is there?

as i see it when i rebuild it the diaphram gasket goes on first, retainer plate , then the diaphram, the spring retainer cup the two locking nuts, second diaphram gasket then spacer ring, spring then lower cup, tighten bolts and refit.

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it is only what i have been told Si, cant tell you any more. i would have thought there would be some adjustment on them.

Лотос - для тех которые знают разницу

ENIGMA for those who are paranoid or download one :)

 

 

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no theres no adjustment on them that can be done really.

only way i could see it being done is by way of a washer or two being put before the retainder plate then the diaphram retainer cup then the nuts, this would push the plates back slightly. im not sure.

pics shown here.

DSCN4293.jpg

DSCN4294.jpg

DSCN4297.jpg

Edited by bigsi
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Last time I took the wastegate apart, a friend drilled out the yoke and fitted a phospor bronze bush for the shaft to slide in. This gets rid of the problem of the top of the yoke corroding and siezing the shaft.

Top tip :lol:

cheers

Mike

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I believe the thickness of the aluminium spacer ring sets the boost pressure...thinner ring=higher pressure as the spring pressure is increased. I'm thinking of modifying mine with a moveable seat under the spring, adjustable for height by a suitable bolt and locknut threaded into the hole at the bottom of the bowl. Something else to play with!

Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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I believe the thickness of the aluminium spacer ring sets the boost pressure...thinner ring=higher pressure as the spring pressure is increased. I'm thinking of modifying mine with a moveable seat under the spring, adjustable for height by a suitable bolt and locknut threaded into the hole at the bottom of the bowl. Something else to play with!

It would not very wise to increase the boost unless carrying out other modifications to the engine. especially the LC lump.

It always was on the edge of reliability and increasing the boost and not changing the timing and or fuel jets sizes WILL detonate number 4 piston to death in pretty quick time I have two rebuilds under my belt for this very reason.

Lotus Technical team even suggests that the timing should be no more than 20 deg btdc dropping back to about 18 at max torque point. The Dom s3 turbo goes to 28 degrees on a standard distributer. It would be a very brave man than held wide open throttle for more than a few seconds on a standard engine with more than standard Boost. :)

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  • 2 weeks later...

Andy..should perhaps have explained that my tired old wastegate spring won't give more than about 5 psi boost at present, and I don't think the springs are available, hence the mod. idea. I'm intrigued as to why it's always no.4 piston which gives you trouble, I would have thought that could have been due to the mixture being supplied to that cylinder by the relevant carb. choke. As to why Lotus should recommend one set of ignition timing specs. and fit a distributor which provides something different....any ideas?

Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Cooling kit, Simon? Tell me more!! Whilst it's all in bits in the workshop, now would be the time...

Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Great stuff, Simon...I've ordered one up! After the Great Overheat on the way to Magny Cours last year, stuck in a jam on the hottest day ever, it's got to be a good idea...I'd never even heard of it until your post. Thanks again!!

JD

Edited by molemot

Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Andy..should perhaps have explained that my tired old wastegate spring won't give more than about 5 psi boost at present, and I don't think the springs are available, hence the mod. idea. I'm intrigued as to why it's always no.4 piston which gives you trouble, I would have thought that could have been due to the mixture being supplied to that cylinder by the relevant carb. choke. As to why Lotus should recommend one set of ignition timing specs. and fit a distributor which provides something different....any ideas?

Sorry been away..

The issue with number 4 is that it does not get cooled as efficiently as the rest, hence the cooling Mod... The HC engine got a higher capacity water pump different inlet manifold with cooling mods and a restrictor in the water flow exiting the head (to water pump) these Mods helped with the detonation and along with 45's different ignition timing, nicosil liners and different pistons allowed the increase in boost.

However even these engines show signs of detonation after a period of time.

The only high mileage engine that i have seen with no signs of detonation is an SE 78,000 miles. however i have never seen a US spec fuel injection engine.

The timing spec for the LC domestic engine are 12 BTDC increasing to 28 deg at 3500rpm.

HC domestic is 10 deg BTDC increasing to 21 deg at 2000rpm then dropping back to 18 Deg at 5000rpm.

Sorry to sound like an anorack but it is a heavily researched subject dear to my heart..........

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