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Discussion Starter #1
Yeeeaaah - it feels great when I hammer the pedal to the metal, the boost preasure rises to 12 psi and my rear tyres is skidding a little due to shear acceleration and leaves a mark from my Goodyear Eagle 225*50 16 GS-D+ - But I think it has a price to boost a L28ET S130 engine so much without any other alterations than a manual boost controller and a home made 76.1mm stainless exhaust pipe.
I have been fault seeking on my engine for quite a while and i found some minor and some major errors on it. The max preasure has been 12 psi from the day i purchased the car a year ago, but the car did'nt run very smooth when i was driving nice and quietly down the road, but when i floored it it felt OK.
The following errors was encountered:

1. Faulty ignition vac. advance....($140) in denmark!!!
2. Ignition timing 9 degrees to retard.
3. Leaking Vacum Crontrol Valve on the intake resulting in high idle....($96).

THE TIMING MARK ON THE FLYWHEEL IS 21 DEGREES OUT OF ALLIGNMENT WITH TDC!!!.

After setting my timing (a month struggle finding the error) I took the car for a test drive with boost set to normal 6.8 psi and the car was running smoothly and silently down the road - quick response even below 2000 rpm which i never had tried before and generaly felt like you could expect from a 200 bhp car.

After the first runs with low boost i raised preasure to 12 psi and listened very carefully under acceleration if there was any indikation of detonation - I could'nt hear any so I found a good highwayand tried to floor it i 5th gear pulling the car to a speedometer indication of 145mph and holdig it there for app 2 miles. When i got home i checked the engine compartment and found it soaked in water coming from the coolant water expansion container - and there was 2 liter of water missing in the radiator.
MY QUESTION IS DID I BLOW UP MY CYLINDERHEADGASKET OR COULD IT BE SOMETHING ELSE??
I naturally reduced boost preasure after that insident and the car runs fine but of course without the same amount of power. There is no water in the oil and it seems that there is no oil in the water. the car did'nt overheat at any point during the run and it was of course up to normal operating temperature.

If the gasket is blown which gasket should i purchase and from where???

When i have the head of should i then mill of the cylinderhead to raise compresion like the Stealth, or should i leave it as it is???

What is O-ringing the block to hold the gasket in place under detonation and how is it performed???

When I am at it I think that I will port match my manifold with the cylinderhead. Is there somthing that I should be cautious about in that operation???

Will i benefit from a Webber big throat trottle body without changing the Airflow meter - where to get one and how much $$???

What are the requirements to my EFI system after these mods and how can i perform them - both cheap and more expensive methods can be considered pleaase ad a price if you have any??

I will ad a intercooler in the same operation so i would like to know wich one is the best and where to get it??

A lot of Q's from a Dane with NEED for speed - I would like to win a competition called the fastest car i denmark, where you should perform 1000m run like a drag racing but about 4.5 times as long followed by a slalom run.

Hope to get many answers to my Q's

Thanks Brian Madsen

PS by the way the car is a 280 ZX TT 2+2 from 83
 

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Re: Q's about TUNING and did i blow up my head gas

I can't really answer any of your questions, but I'll try to make you feel better about your over-heating. Normally when we accelerate hard the throttle is WOT(Wide Open Throttle) for only afew seconds, even then, we come off the throttle for shifting. When you top out a car you should expect the engine to run hot. The extra wind thru the radiator doesn't really help the cooling any more then when your going moderate speeds. I also have a jeep and many other jeep people have over heating problems. The major problem is that we idle for 2 hours then go WOT up a hill or thru some mud then idle some more. The heat that is generated by the engine during WOT takes along time to cool down at idle. The bottom line is that your radiator was selected to deal only with normal conditions, if your going to go around full throttle you need to recalculate the needed cooling capacity of your engine. Maybe a aluminum radiator with a larger reserve tank would help.

> Yeeeaaah - it feels great when I hammer the
> pedal to the metal, the boost preasure rises
> to 12 psi and my rear tyres is skidding a
> little due to shear acceleration and leaves
> a mark from my Goodyear Eagle 225*50 16
> GS-D+ - But I think it has a price to boost
> a L28ET S130 engine so much without any
> other alterations than a manual boost
> controller and a home made 76.1mm stainless
> exhaust pipe.
> I have been fault seeking on my engine for
> quite a while and i found some minor and
> some major errors on it. The max preasure
> has been 12 psi from the day i purchased the
> car a year ago, but the car did'nt run very
> smooth when i was driving nice and quietly
> down the road, but when i floored it it felt
> OK.
> The following errors was encountered:

> 1. Faulty ignition vac. advance....($140) in
> denmark!!!
> 2. Ignition timing 9 degrees to retard.
> 3. Leaking Vacum Crontrol Valve on the
> intake resulting in high idle....($96).

> THE TIMING MARK ON THE FLYWHEEL IS 21
> DEGREES OUT OF ALLIGNMENT WITH TDC!!!.

> After setting my timing (a month struggle
> finding the error) I took the car for a test
> drive with boost set to normal 6.8 psi and
> the car was running smoothly and silently
> down the road - quick response even below
> 2000 rpm which i never had tried before and
> generaly felt like you could expect from a
> 200 bhp car.

> After the first runs with low boost i raised
> preasure to 12 psi and listened very
> carefully under acceleration if there was
> any indikation of detonation - I could'nt
> hear any so I found a good highwayand tried
> to floor it i 5th gear pulling the car to a
> speedometer indication of 145mph and holdig
> it there for app 2 miles. When i got home i
> checked the engine compartment and found it
> soaked in water coming from the coolant
> water expansion container - and there was 2
> liter of water missing in the radiator.
> MY QUESTION IS DID I BLOW UP MY
> CYLINDERHEADGASKET OR COULD IT BE SOMETHING
> ELSE??
> I naturally reduced boost preasure after
> that insident and the car runs fine but of
> course without the same amount of power.
> There is no water in the oil and it seems
> that there is no oil in the water. the car
> did'nt overheat at any point during the run
> and it was of course up to normal operating
> temperature.

> If the gasket is blown which gasket should i
> purchase and from where???

> When i have the head of should i then mill
> of the cylinderhead to raise compresion like
> the Stealth, or should i leave it as it
> is???

> What is O-ringing the block to
> hold the gasket in place under detonation
> and how is it performed???

> When I am at it I think that I will port
> match my manifold with the cylinderhead. Is
> there somthing that I should be cautious
> about in that operation???

> Will i benefit from a Webber big throat
> trottle body without changing the Airflow
> meter - where to get one and how much $$???

> What are the requirements to my EFI system
> after these mods and how can i perform them
> - both cheap and more expensive methods can
> be considered pleaase ad a price if you have
> any??

> I will ad a intercooler in the same
> operation so i would like to know wich one
> is the best and where to get it??

> A lot of Q's from a Dane with NEED for speed
> - I would like to win a competition called
> the fastest car i denmark, where you should
> perform 1000m run like a drag racing but
> about 4.5 times as long followed by a slalom
> run.

> Hope to get many answers to my Q's

> Thanks Brian Madsen

> PS by the way the car is a 280 ZX TT 2+2
> from 83
 

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Joined
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1,323 Posts
Re: Q's about TUNING and did i blow up my head gas

> Yeeeaaah - it feels great when I hammer the
> pedal to the metal, the boost preasure rises
> to 12 psi and my rear tyres is skidding a
> little due to shear acceleration and leaves
> a mark from my Goodyear Eagle 225*50 16
> GS-D+ - But I think it has a price to boost
> a L28ET S130 engine so much without any
> other alterations than a manual boost
> controller and a home made 76.1mm stainless
> exhaust pipe.
> I have been fault seeking on my engine for
> quite a while and i found some minor and
> some major errors on it. The max preasure
> has been 12 psi from the day i purchased the
> car a year ago, but the car did'nt run very
> smooth when i was driving nice and quietly
> down the road, but when i floored it it felt
> OK.
> The following errors was encountered:

> 1. Faulty ignition vac. advance....($140) in
> denmark!!!
> 2. Ignition timing 9 degrees to retard.
> 3. Leaking Vacum Crontrol Valve on the
> intake resulting in high idle....($96).

> THE TIMING MARK ON THE FLYWHEEL IS 21
> DEGREES OUT OF ALLIGNMENT WITH TDC!!!.

> After setting my timing (a month struggle
> finding the error) I took the car for a test
> drive with boost set to normal 6.8 psi and
> the car was running smoothly and silently
> down the road - quick response even below
> 2000 rpm which i never had tried before and
> generaly felt like you could expect from a
> 200 bhp car.

> After the first runs with low boost i raised
> preasure to 12 psi and listened very
> carefully under acceleration if there was
> any indikation of detonation - I could'nt
> hear any so I found a good highwayand tried
> to floor it i 5th gear pulling the car to a
> speedometer indication of 145mph and holdig
> it there for app 2 miles. When i got home i
> checked the engine compartment and found it
> soaked in water coming from the coolant
> water expansion container - and there was 2
> liter of water missing in the radiator.
> MY QUESTION IS DID I BLOW UP MY
> CYLINDERHEADGASKET OR COULD IT BE SOMETHING
> ELSE??
> I naturally reduced boost preasure after
> that insident and the car runs fine but of
> course without the same amount of power.
> There is no water in the oil and it seems
> that there is no oil in the water. the car
> did'nt overheat at any point during the run
> and it was of course up to normal operating
> temperature.

> If the gasket is blown which gasket should i
> purchase and from where???
HKS SIMPLY MAKES THE NICEST GASKET AROUND. I RUN 19 PSI DAILY WITH NO PROBLEMS AND THE GASKET CAN TAKE ALOT MORE. $130 FOR 1MM AND $160 FOR 2MM THICH GASKETS.
> When i have the head of should i then mill
> of the cylinderhead to raise compresion like
> the Stealth, or should i leave it as it
> is???
NEVER LISTEN TO A THING THAT GUY POSTS. IF YOU MILL THE HEAD, YOU WILL RAISE COMPRESSION AND ALSO THROW OFF YOUR CAM TIMING. YOU WOULD THEN NEED TO SHIM THE CAM TOWERS OR BUY AN ADJUSTABLE CAM SPROCKET. I KNOW GUYS RUNNING 7.4:1 COMPRESSION AND RUNNING 12.5'S IN THE 1/4. THE LOWER COMPRESSION WILL ALLOW YOU TO RUN HIGHER BOOST LEVELS.
> What is O-ringing the block to
> hold the gasket in place under detonation
> and how is it performed???
O-RINGING IS CUTTING A SMALL GROOVE AROUND THE CYLINDER BORE. WHEN YOU TIGHTEN DOWN THE HEAD, THE GASKET IS FORCED INTO THE GROOVE CREATING A SEAL THAT IS DIFFICULT TO BREAK. THE HKS AND SOME ARP HEAD STUDS WILL GIVE YOU ALL THE PROTECTION YOU WILL NEED EVEN AT 25PSI BOOST. ALTHOUGH IT CANNOT HURT TO HAVE IT O-RINGED, IT IS NOT ABSOLUTELY NECESSARY.
> When I am at it I think that I will port
> match my manifold with the cylinderhead. Is
> there somthing that I should be cautious
> about in that operation???
NEVER MAKE THE MANIFOLD PORTS LARGER THAN THE HEAD PORTS. THIS WILL CAUSE YOU TO FORM A LIP THAT WILL ABRUPT FLOW AND KILL PERFORMANCE. USE A GASKET AS A TEMPLATE TO BOTH YOUR MANIFOLD AND HEAD. LINE UP THE BOLT HOLES AND MARK WHERE METAL IS TO BE REMOVED.
> Will i benefit from a Webber big throat
> trottle body without changing the Airflow
> meter - where to get one and how much $$???
YOU WILL BENEFIT IN PERFORMANCE, I HAVE NO IDEA THE COST.
> What are the requirements to my EFI system
> after these mods and how can i perform them
> - both cheap and more expensive methods can
> be considered pleaase ad a price if you have
> any??
HAVE AFTERMARKET FUEL/IGNITION COMPUTER, HAVE NO IDEA. YOU CAN BUY THE UPGRADE ECU FROM MOTORSPORT.
> I will ad a intercooler in the same
> operation so i would like to know wich one
> is the best and where to get it??
****, YOU RUN 12PSI WITH NO INTERCOOLER! DEATH WISH ON THE MOTOR????? SPEARCO MAKES GOOD INTERCOOLERS, ALSO BELL ENGINEERING MAKES A NICE INTERCOOLER FOR CHEAP.
> A lot of Q's from a Dane with NEED for speed
> - I would like to win a competition called
> the fastest car i denmark, where you should
> perform 1000m run like a drag racing but
> about 4.5 times as long followed by a slalom
> run.

> Hope to get many answers to my Q's

> Thanks Brian Madsen

> PS by the way the car is a 280 ZX TT 2+2
> from 83
 

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Re: Q's about TUNING and did i blow up my head gas

What problably happened when you were going that fast was the lower rad hose collapsed and the water pump pushed the water out the overflow. If the engine is still running fine i wouldn't worry about it.
 

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Re: Q's about TUNING and did i blow up my head gas

> HKS SIMPLY MAKES THE NICEST GASKET AROUND. I
> RUN 19 PSI DAILY WITH NO PROBLEMS AND THE
> GASKET CAN TAKE ALOT MORE. $130 FOR 1MM AND
> $160 FOR 2MM THICH GASKETS.

The Nissan Motorsport o-ringed gasket is an excellent piece, also, but it is quite expensive, and requires machining of the block. Actually, at 12psi, the stock head gasket should work fine, _IF_ you make sure that the head bolts are torqued properly (65ft-lbs for the ZXT), in the proper sequence, and retorque them periodically.
You description didn't sound like a blown head gasket, though.

> NEVER LISTEN TO A THING THAT GUY POSTS. IF
> YOU MILL THE HEAD, YOU WILL RAISE
> COMPRESSION AND ALSO THROW OFF YOUR CAM
> TIMING. YOU WOULD THEN NEED TO SHIM THE CAM
> TOWERS OR BUY AN ADJUSTABLE CAM SPROCKET. I
> KNOW GUYS RUNNING 7.4:1 COMPRESSION AND
> RUNNING 12.5'S IN THE 1/4. THE LOWER
> COMPRESSION WILL ALLOW YOU TO RUN HIGHER
> BOOST LEVELS.

Agreed However, if you are looking for more moderate (say, <270hp) power levels, a slight increase in compression (8.5:1 or less) would give better off-boost response and better overall efficiency, at the expense of ultimate power.

> O-RINGING IS CUTTING A SMALL GROOVE AROUND
> THE CYLINDER BORE. WHEN YOU TIGHTEN DOWN THE
> HEAD, THE GASKET IS FORCED INTO THE GROOVE
> CREATING A SEAL THAT IS DIFFICULT TO BREAK.

Often a metal o-ring is actually fitted in the groove, in order to crush the gasket even tigher around the perimeter of the cylinder bore.

> NEVER MAKE THE MANIFOLD PORTS LARGER THAN
> THE HEAD PORTS. THIS WILL CAUSE YOU TO FORM
> A LIP THAT WILL ABRUPT FLOW AND KILL
> PERFORMANCE. USE A GASKET AS A TEMPLATE TO
> BOTH YOUR MANIFOLD AND HEAD. LINE UP THE
> BOLT HOLES AND MARK WHERE METAL IS TO BE
> REMOVED.

Also, unless you really know what you are doing, or know someone who does, don't mess with the head ports. It's really easy to make it flow worse, and alot more difficult to improve it.

> ****, YOU RUN 12PSI WITH NO INTERCOOLER!
> DEATH WISH ON THE MOTOR????? SPEARCO MAKES
> GOOD INTERCOOLERS, ALSO BELL ENGINEERING
> MAKES A NICE INTERCOOLER FOR CHEAP.

Geez...no kidding! You should really look into at least getting a rising rate fuel pressure regulator, and a fuel pump with sufficient high pressure fuel flow capabilities. The stock FI system wasn't sized to supply enough fuel for an honest 12psi of boost. Turning up the boost ONLY increases the amount of air going into the motor. If you don't make sure that you have enough fuel to go with it, bad things will happen. Things that are alot more expensive than replacing a head gasket...
 

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Discussion Starter #6
Re: Thanks

> The Nissan Motorsport o-ringed gasket is an
> excellent piece, also, but it is quite
> expensive, and requires machining of the
> block. Actually, at 12psi, the stock head
> gasket should work fine, _IF_ you make sure
> that the head bolts are torqued properly
> (65ft-lbs for the ZXT), in the proper
> sequence, and retorque them periodically.
> You description didn't sound like a blown
> head gasket, though.

> Agreed However, if you are looking for more
> moderate (say, Often a metal o-ring is
> actually fitted in the groove, in order to
> crush the gasket even tigher around the
> perimeter of the cylinder bore.

> Also, unless you really know what you are
> doing, or know someone who does, don't mess
> with the head ports. It's really easy to
> make it flow worse, and alot more difficult
> to improve it.

> Geez...no kidding! You should really look
> into at least getting a rising rate fuel
> pressure regulator, and a fuel pump with
> sufficient high pressure fuel flow
> capabilities. The stock FI system wasn't
> sized to supply enough fuel for an honest
> 12psi of boost. Turning up the boost ONLY
> increases the amount of air going into the
> motor. If you don't make sure that you have
> enough fuel to go with it, bad things will
> happen. Things that are alot more expensive
> than replacing a head gasket...

First of all, I do NOT have a death wish for my motor, but thanks to you and Z240 TURBO I now drive with the more moderate of 6.8 psi until i have located the fault on my engine (headgasket or collapsed lower radiator hose). I can understand on you guys that it is NOT recomendable to boost a standard L28ET engine that much without making any other alterations, but this amount of boost was preset by the guy from who i purchased the car. The car has been running with up to 12 psi boost preasure for app 7500 miles. I don't know if there has been made any alterations to the FI, but i don't think so. I haven't heard any knocking/pinging sounds from the engine compartment so I hope that the engine is OK (Please let luck be with me!).

You write that i should get another preasure regulator, can you recommend one or can i alterate my standard regulator to rise fuel preasure??

And at last, Which fuel pump will you recommend - The Stealth Z guy uses at pump from a Porche Turbo - is there any other alternatives???

Thank you for answering most of my Q's and i hope You will answer to some of my other Q's as i get along with my project.

Brian the more enlightend
 

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Discussion Starter #7
Re: Thanks - I hope you are right!! (n/c)

> What problably happened when you were going
> that fast was the lower rad hose collapsed
> and the water pump pushed the water out the
> overflow. If the engine is still running
> fine i wouldn't worry about it.

(n/c)
 

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107,695 Posts
Discussion Starter #8
Re: Thanks -but the car does'nt overheat(n/c)

> I can't really answer any of your questions,
> but I'll try to make you feel better about
> your over-heating. Normally when we
> accelerate hard the throttle is WOT(Wide
> Open Throttle) for only afew seconds, even
> then, we come off the throttle for shifting.
> When you top out a car you
> should expect the engine to run hot. The
> extra wind thru the radiator doesn't really
> help the cooling any more then when your
> going moderate speeds. I also have a jeep
> and many other jeep people have over heating
> problems. The major problem is that we idle
> for 2 hours then go WOT up a hill or thru
> some mud then idle some more. The heat that
> is generated by the engine during WOT takes
> along time to cool down at idle. The bottom
> line is that your radiator was selected to
> deal only with normal conditions, if your
> going to go around full throttle you need to
> recalculate the needed cooling capacity of
> your engine. Maybe a aluminum radiator with
> a larger reserve tank would help.

(n/c)
 
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