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The mkiv Supra Owners Club

Warning for nat guys and the head gasket.


herbiemercman

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Is the stock NA head gasket only 0.6mm? I rather doubt it. Fitting a 1.3mm gasket is not going to kill power by 25% even if it is 0.6mm. You have other issues, for sure. Start by buying a cheap mechanical boost gauge (Raceparts UK do good ones that are far from expensive) and some suitable hose (rubber NOT silicone) to run from the MAP sensor area to inside the car through a side window. go take a drive and report the boost... Stock up on petrol and tinned food whilst out, before fuel and food rationing start... ;)

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Hi Chris, Your posting must have given me the "Midas" touch, after examining all my boost pipe connections, which looked ok, i then removed all the pipe system, what a relief i found!

The pipe which connects to the air intake manifold had a 3" tear in it, a mega boost loss.

 

I replaced the pipe and the performance came back to the best it has been since the original NAT build. Contrary to the advise i was given on how much BHP i would lose on the CR of the thicker gasket, you were correct stating the reduction would be minimal.

 

For three weeks i have been struggling and had lots of support and help from the club members, some were addament about finding the boost leak, but it was well hidden, also it did not help that the boost gauge was not working, and still is not working.

Even if i did the capping off the turbo intake test to see if the engine stopped, it would still leave me trying to locate the leak, i only found it today because i threw the pipes off in rage.

 

I was close to contacting you and paying a visit to Nantwich. Herbie. (Adrian's Brother).

Edited by herbiemercman (see edit history)
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Hi Chris, Your posting must have given me the "Midas" touch, after examining all my boost pipe connections, which looked ok, i then removed all the pipe system, what a relief i found!

The pipe which connects to the air intake manifold had a 3" tear in it, a mega boost loss.

 

I replaced the pipe and the performance came back to the best it has been since the original NAT build. Contrary to the advise i was given on how much BHP i would lose on the CR of the thicker gasket, you were correct stating the reduction would be minimal.

 

For three weeks i have been struggling and had lots of support and help from the club members, some were addament about finding the boost leak, but it was well hidden, also it did not help that the boost gauge was not working, and still is not working.

Even if i did the capping off the turbo intake test to see if the engine stopped, it would still leave me trying to locate the leak, i only found it today because i threw the pipes off in rage.

 

I was close to contacting you and paying a visit to Nantwich. Herbie. (Adrian's Brother).

 

Pleased to hear found issue and now she’s running great again

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Hi Chris, Your posting must have given me the "Midas" touch, after examining all my boost pipe connections, which looked ok, i then removed all the pipe system, what a relief i found!

The pipe which connects to the air intake manifold had a 3" tear in it, a mega boost loss.

 

I replaced the pipe and the performance came back to the best it has been since the original NAT build. Contrary to the advise i was given on how much BHP i would lose on the CR of the thicker gasket, you were correct stating the reduction would be minimal.

 

For three weeks i have been struggling and had lots of support and help from the club members, some were addament about finding the boost leak, but it was well hidden, also it did not help that the boost gauge was not working, and still is not working.

Even if i did the capping off the turbo intake test to see if the engine stopped, it would still leave me trying to locate the leak, i only found it today because i threw the pipes off in rage.

 

I was close to contacting you and paying a visit to Nantwich. Herbie. (Adrian's Brother).

 

Good man, glad it was something fairly trivial! Dropping the CR by one or so won't lose 25% power, and it can be made up with more boost although off boost performance will be a tad less sparkling.

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Glad you got there in the end mate. If you'd blocked off the turbo, you'd have heard where the leak was coming from a mile off with how big a tear was in the hose.

 

Might still be worth having a look at the map to make sure everything's tickety boo after dropping the CR. It might be fine, but it's good peace of mind.

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