Stock twins

[Nickmms94]

Hi guys I’ve taken the twins off trouble shooting a misfire when the second turbo is supposed to kick in it just doesn’t, anyway This is the state they are in I don’t really want to go to single turbo so need help on what options I have or if anyone has any for sale ?

 

[Nickmms94]

also to add the actual turbines are in good condition with no excess play or end float.

 

[Spendyrx]

Tbh they don't actually look that bad. I'd maybe try getting that crack welded up over buying another mani!
I bet after you put all that back together you still have the same issue!

 

[Nickmms94]

do the cracks not effect performance ? surely with the cracks there that flaps not blocking off when its supposed too and in turn the secondary turbo would be spooling more than its supposed too at the pre spool stage ? yes I do expect I have the same issue but after pressure testing and vacuum testing all the pipes to the solenoid box I wanted to see everything was mechanically ok with the turbos and flaps etc. the problem has got to be something really stupid lol but im enjoying finding out how everything works haha

 

[jdmr_neil]

Now they don't look to bad to me either, mine were loads worse and still boosting hard on both turbos.

 

[ascari]

do the cracks not effect performance ? surely with the cracks there that flaps not blocking off when its supposed too and in turn the secondary turbo would be spooling more than its supposed too at the pre spool stage ? yes I do expect I have the same issue but after pressure testing and vacuum testing all the pipes to the solenoid box I wanted to see everything was mechanically ok with the turbos and flaps etc. the problem has got to be something really stupid lol but im enjoying finding out how everything works haha

Did you take the twins off with the engine in or out? I maybe doing the same, and wondered if you had any advice now you've done it

 

[Nickmms94]

I took them out with the engine in wasn't too bad, but did find out after that if you remove the engine mounts and jack the engine up around two inches it will help a lot as the steering rack is in the way. it can be done without doing this though as I managed haha but id defo do this next time.

 

[Spendyrx]

Yeah you'd defo have a boost issue with cracks but as neil says, if I recall, his were absolutely dusgusting and he was boosting 18psi on his twins wasn't it neil?
Obviously now yours are off you'd defo be wanting to look at doing something about the crack you have, but personally I don't think it would create 'no secondary boost' you'd just be seeing something silly like 6psi! As I say, I'd personally look at having it welded as it's in pretty decent shape and also you have no oil leaks or shaft play which is really good!

 

[ascari]

I took them out with the engine in wasn't too bad, but did find out after that if you remove the engine mounts and jack the engine up around two inches it will help a lot as the steering rack is in the way. it can be done without doing this though as I managed haha but id defo do this next time.

I'm a little green... I would need to actually remove the mounts?

 

[ascari]

Yeah you'd defo have a boost issue with cracks but as neil says, if I recall, his were absolutely dusgusting and he was boosting 18psi on his twins wasn't it neil?
Obviously now yours are off you'd defo be wanting to look at doing something about the crack you have, but personally I don't think it would create 'no secondary boost' you'd just be seeing something silly like 6psi! As I say, I'd personally look at having it welded as it's in pretty decent shape and also you have no oil leaks or shaft play which is really good!

Can you use the 99 spec boost dial on the dash, to accurately measure psi? If so, should it be showing 10-8-10 psi's when boosting to the red line?

 

[Spendyrx]

No idea! someone like @Ceylon could give you a better idea on that but I'm assuming you could as a boost gauge is a boost gauge right! You should be seeing 10 8 10 though! Because I have a decat mid mine tends to creep up to about 13psi in high revs in 4th and 5th gear!

 

[Nickmms94]

I'm a little green... I would need to actually remove the mounts?

Im
Not fully sure as I didn’t do it but I’m sure you’d just unbolt the bracket that joins the engine to the body/subframe, usually a rubber mount.

 

[rob fd]

No idea! someone like @Ceylon could give you a better idea on that but I'm assuming you could as a boost gauge is a boost gauge right! You should be seeing 10 8 10 though! Because I have a decat mid mine tends to creep up to about 13psi in high revs in 4th and 5th gear!

What numbers are you making?

 

[Nickmms94]

Yeah you'd defo have a boost issue with cracks but as neil says, if I recall, his were absolutely dusgusting and he was boosting 18psi on his twins wasn't it neil?
Obviously now yours are off you'd defo be wanting to look at doing something about the crack you have, but personally I don't think it would create 'no secondary boost' you'd just be seeing something silly like 6psi! As I say, I'd personally look at having it welded as it's in pretty decent shape and also you have no oil leaks or shaft play which is really good!

Yea I’m going to see if I can get it welded by someone, I don’t think this is the problem with the car though. I’ve tested all the fuel side and all is ok so it’s got to be something like a boost leak as it idles rough sometimes hunting and then full throttle it starts to miss around 4K when the second turbo is supposed to come in. It’s almost like the Ecu is throwing the fuel in as there’s either too much air going in so it’s trying to compensate or there’s just no secondary turbo kicking in and the Ecu is putting fuel in as it’s thinking the turbos working but it’s not getting the air.

 

[ascari]

What numbers are you making?

Now I know the gauge should be accurate, I'll test it out. I do know that if I floor it in 1st or 2nd, it won't boost, but it will boost well if I press the accelerator down half way! Is this normal, a limiter maybe?

 

[rob fd]

Now I know the gauge should be accurate, I'll test it out. I do know that if I floor it in 1st or 2nd, it won't boost, but it will boost well if I press the accelerator down half way! Is this normal, a limiter maybe?

Definetly not normal. You should be able to mash the throttle down. Im on stock twins and it's very responsive and boosts up very quickly anywhere in the rev range.

 

[ascari]

Definetly not normal. You should be able to mash the throttle down. Im on stock twins and it's very responsive and boosts up very quickly anywhere in the rev range.

Oh. Vacuum related perhaps?

 

[Ceylon]

The late boost gauges are not that accurate tbh, I wouldn't trust them for a good reading.
Those cracks wont affect performance yet, but I'd be tempted to try and weld it up if you've got the time.
Grind down into the cracks until they stop, make a V shape and weld them back up with a cast specific rod. I think when I last did some I preheated the entire hot side and cooled it all down slowly to try and avoid cracks, worked pretty well.

 

[jdmr_neil]

Yeah you'd defo have a boost issue with cracks but as neil says, if I recall, his were absolutely dusgusting and he was boosting 18psi on his twins wasn't it neil?
Obviously now yours are off you'd defo be wanting to look at doing something about the crack you have, but personally I don't think it would create 'no secondary boost' you'd just be seeing something silly like 6psi! As I say, I'd personally look at having it welded as it's in pretty decent shape and also you have no oil leaks or shaft play which is really good!

Yeah 17-18 psi and were still pulling hard when i removed them. Those cracks won't affect performance at all but obviously while they're off, might aswell fix it.

Your boost issue will more likely be a control issue rather than the twin pack itself. While it's off though check the actuators are working correctly as they cause secondary issues when they fail.

 

[jdmr_neil]

Plugs

Yea I’m going to see if I can get it welded by someone, I don’t think this is the problem with the car though. I’ve tested all the fuel side and all is ok so it’s got to be something like a boost leak as it idles rough sometimes hunting and then full throttle it starts to miss around 4K when the second turbo is supposed to come in. It’s almost like the Ecu is throwing the fuel in as there’s either too much air going in so it’s trying to compensate or there’s just no secondary turbo kicking in and the Ecu is putting fuel in as it’s thinking the turbos working but it’s not getting the air.

Plugs, leads etc good? What ecu? Standard car?