[bambill]

You can add say a 1mm or so shim, I strongly advise against adding multiple shims to reduce fuelling on a large scale, this does affect timing curves.
As does when playing with the fuel screw, but also, the fuel screw will affect things from idle all the way through, not a smart thing to do.
You mention Redarc gauges, hmmm.
Just a observation, my eBoost street boost readout is far from accurate, the Autometer gauge and the dyno which uses a transducer are within a psi or so of each other.
Few gauges that give weird readings on our dyno, Redarc and SAAS, about on a par, is another with flashing ligths and **** that I cant remember the name of that also give weird readngs.

 

[geeyoutoo]

You can add say a 1mm or so shim, I strongly advise against adding multiple shims to reduce fuelling on a large scale, this does affect timing curves.
As does when playing with the fuel screw, but also, the fuel screw will affect things from idle all the way through, not a smart thing to do.
You mention Redarc gauges, hmmm.
Just a observation, my eBoost street boost readout is far from accurate, the Autometer gauge and the dyno which uses a transducer are within a psi or so of each other.
Few gauges that give weird readings on our dyno, Redarc and SAAS, about on a par, is another with flashing ligths and **** that I cant remember the name of that also give weird readngs.

Interesting, my Autometer and the gauge on Peters dyno match near as buggery, the digital boost gauge in my Coolingmist WM controller (that flashes like crazy, so it is out of the way) reads 1psi lower.

 

[GQshayne]

With 14 psi springs, I could still get good boost too, but the 26psi combo does things better. I cannot explain the technicalities though!! LOL

 

[dirty_td42]

You can add say a 1mm or so shim, I strongly advise against adding multiple shims to reduce fuelling on a large scale, this does affect timing curves.
As does when playing with the fuel screw, but also, the fuel screw will affect things from idle all the way through, not a smart thing to do.
You mention Redarc gauges, hmmm.
Just a observation, my eBoost street boost readout is far from accurate, the Autometer gauge and the dyno which uses a transducer are within a psi or so of each other.
Few gauges that give weird readings on our dyno, Redarc and SAAS, about on a par, is another with flashing ligths and **** that I cant remember the name of that also give weird readngs.

My eboost was also 2-3psi different to my old vdo gauge, so i suspect the redarc is reading closer to the truth, but i will compare it to the old vdo. I do in a lot of ways prefer the vdos but i just couldnt monitor everything i wanted to with a 3 gauge pillar mount. At least my redarc boost gauge is the digital one so its not notchy like the one with the needle, that would drive me nuts. If 27psi as the redarc suggests is accurate then that could explain my high egt. Im guessing i probably need 30psi with the borg to obtain a decent afr up top, maybe more, i think someone said the 6758 was efficient to 32psi? Ive upped the wastegate springs tonight to 26psi like Pete suggested and will reinstall with 4 Turns of preload, and hopefully now i will be able to get more than 27psi max(redarc gauge)more than likely my egts will come down. ideally id like to run as close to 30 as possible, hopefully wont have to shim.

 

[Jjjag2099]

What is the best spring arrangement for a stock 11mm

 

[Jjjag2099]

For the turbo to adapter plate what size stud works for the short side pretty tight

 

[dirty_td42]

For the turbo to adapter plate what size stud works for the short side pretty tight

Hey mate i ended up cutting that stud to size.

 

[ROGQ]

Has anyone opted to take a die grinder to the T3-T25 adaptor? I’ve got the 2 piece style from GCG that most people are using but where the T3 plate sits on my manifold, the adaptor is approximately 5mm smaller on both the long and short edges compared to the manifold opening.

I’ve been reading how you don’t want any “steps” in the flow direction when porting, so I was curious if people have been just leaving this or taking to it with a die grinder?

 

[bennytd42]

Has anyone opted to take a die grinder to the T3-T25 adaptor? I’ve got the 2 piece style from GCG that most people are using but where the T3 plate sits on my manifold, the adaptor is approximately 5mm smaller on both the long and short edges compared to the manifold opening.

I’ve been reading how you don’t want any “steps” in the flow direction when porting, so I was curious if people have been just leaving this or taking to it with a die grinder?

Yeah. Match it all up. It's not going to hurt and it only cost time and effort

 

[GQshayne]

I cannot recall whether it matched my manifold or not, but I would be matching it if it is not the right size.

 

[AngryBird]

I'm interested in upgrading the turbo in the GU - exploring all offerings. Before I embark on the 1710 post, 86 page adventure, is there a summary?

 

[GQshayne]

In short (my version), the EFR is a high quality turbo in terms of its manufacture, that works well even with 10mm injector pumps. With 12mm pumps it is capable of a lot of power and torque, and yet is still quite responsive. Many of us have gone all out with electronic boost control etc, to get the best out of it, but that does not mean it cannot be set up with a basic manual boost controller as well. It is not cheap, but it is one of the best options available.

 

[dirty_td42]

Im finding the tuning quite fiddly. It doesnt help that there is nobody up here with a dyno that knows what they are doing. Will be dropping in to Ufi early next year when i drive down to Perth. Mine is still a little doey down low and a bit smokey. But otherwise once it gets going is very responsive. Maybe a slight timing adjustment is all it will take to sort the bottom end and the smoke out. I have played with the timing quite a bit though. Ive had a distinct drop in top end performance and lack of smoke indicitive of being too far retarded, as well as had really good top end and even worse bottom end with more smoke than i have now which would indicate a little too much advance. its somewhere in between now. With the ufi pump it is definately a lot more noticable when small timing adjustments are made. There are some with the opinion that the turbo may be too big to get the bottom end performance i am expecting, but there are also several people on here who have reported very early spool as well. I cant really make that call until ive had a proper tune.

 

[simcoe]

I wouldn’t say very early spool, [email protected] ish, when at full 3.5t weight it didn’t really start to boogie until 16-1700.
Under 1500 is near non eventful if you are presented with a hill, feeding it fuel at those rpms will just make smoke and hinder spool up. Revs hard from from once it gets going though to redline.

I should have my motor back in over the wknd again and now my rig is near a tonne lighter I will probably like it again.

 

[dirty_td42]

I wouldn’t say very early spool, [email protected] ish, when at full 3.5t weight it didn’t really start to boogie until 16-1700.
Under 1500 is near non eventful if you are presented with a hill, feeding it fuel at those rpms will just make smoke and hinder spool up. Revs hard from from once it gets going though to redline.

I should have my motor back in over the wknd again and now my rig is near a tonne lighter I will probably like it again.

Yeh ok maybe my expectations arent quite right or perhaps the ones ive been reading about with the insane spool are silvertops. Is your new motor a factory turbo or a silvertop?

 

[simcoe]

Yeh ok maybe my expectations arent quite right or perhaps the ones ive been reading about with the insane spool are silvertops. Is your new motor a factory turbo or a silvertop?

The block I have now is a silver top using its cam, timing gears and lifters, and t backing plate, timing case and crank etc. but those figures were with the old t motor.

I haven’t driven it yet with the 6758. I trialled the 6258 for a few hundred kms. With out some serious tuning not sure it would have been worth it.

so pulled the motor back out to fix some oil leaks and swap turbos back to the 67.

 

[dirty_td42]

The block I have now is a silver top using its cam, timing gears and lifters, and t backing plate, timing case and crank etc. but those figures were with the old t motor.

I haven’t driven it yet with the 6758. I trialled the 6258 for a few hundred kms. With out some serious tuning not sure it would have been worth it.

so pulled the motor back out to fix some oil leaks and swap turbos back to the 67.

Nice, will be interested to see if you notice a difference with the new motor once the 6758 is back on as you now have a silvertop camshaft which ive heard makes an improvement. Lets hope this is the end of your reliability issues as well. I was also considering the 6258 at one stage because i dont go past 3000 rpm very often and thought the smaller turbo may be a better match for my driving style. My tinkering is at minimum at the moment as most days are up at 40 degrees.

 

[GQshayne]

It has now been confirmed that the camshafts between the two engines are the same lift and duration, but are not interchangeable. The difference is in the timing. So those of us with T spec engines can change the timing of the cam to Silvertop spec by moving 1 tooth on the cam gear. @OldMav can confirm this, but I think it is about 5 degrees.

 

[boosted_zd]

So after trying everything to get my 6758 to spool up properly under 2k I pulled it off last week and installed a 16g 6cm to test if the turbo was just too big.

What do you know the 16g spools up identical to the efr

So this leaves me with either the pump or the cam, I was actually making a few calls this week about sourcing a silvertop cam but if the above is correct then that will save me a LOT of headaches.

As for 16g vs efr the 16g has better torque in the lower rpms obviously but the funny thing is it seems to take more to get going hard to explain

 

[GQshayne]

I am reluctant to say too much about the cam, as it is only second hand info from Oldmav. Best let him confirm the details. I supplied him the Silvertop camshaft and timing gear, but he did the testing to see what was what. This testing was done on a stationary engine, not a running engine.

But from memory the Silvertop cam cannot be fitted to the T motor, as there are difference in the cam followers etc. Profile of the cam is the same, it is just that the timing gear on the T motor has 5 degrees more retardation, which works out to be one tooth. So advancing the T motor timing gear 5 degrees (one tooth) gives it the same as the Silvertop specification. Piston to valve clearance is ok.

The Silvertop engines have been shown to respond earlier in the rev range, make peak torque closer to 900nm instead of 750nm, and peak power of about 180kw instead of 200kw. Rough numbers there.

Peter can confirm this when he sees it, to ensure I have the details correct.