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Advice needed on single turbo conversion parts with usage of an 67mm dbb unit.


Mario
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Best Turbo Gurus,

I need some help/advice with my single turbo conversion parts which I want to buy in the coming year, but haven’t really a clue what to choose, as there is lots of performance parts available out there.

The turbo is already been bought, it’s an precision t67 dbb unit with an ar .81

I’m leaning towards the twin waste gate turbo kit which Paul Whiffin supplies,

But wan’t the best performance which can be achieved with this 67mm turbo,

What(staggered?) cams do I need and why, what size of injectors do I need and why, what fuelling pump(s) do I need to buy for the best possible set-up.

I want to use my standard intake manifold for the beginning,

And the stand alone management system I will leave open for the tuner to decide what he thinks is best.

What figures are possible, and if you can please add some information why particular parts are better performing in this set-up over other parts, that would be much appreciated.

Thanks Mario,

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I can only go by my personal experience, hopefully this will be useful:

 

A T67 will hit 600bhp no problems around 1.5bar of boost. It will boost higher if you have the supporting mods to enable it.

 

256in/264ex or 264in/264ex cams are a good combo, they don't sacrifice much down low but the engine will pull all the way to the redline instead of chokcing up above 6000rpm.

 

Injectors you will need 700cc minimum, 850cc would give more headroom. One walbro pump can fuel this power, but no higher, you'd need a twin pump setup or possibly one of the Bosch pumps.

 

One HKS style wastegate is all you need, anything else is overkill :)

 

That's about it really, a beefier clutch is necesary but everything else will be fine. Although it really depends on what you mean by "best performance" :)

 

-Ian

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Thanks IanC,

What parts are needed to boost above 1,5 bar?

Will 264in/272ex or 272in/272ex in comparison with the 256in/264ex or 264in/264ex perform better or worse.

850cc to give me some headroom, will 1000cc work too or will an larger injector size give trouble during map sessions.

What does overkill mean? I'm actually amazed to hear that,:), can you please explain why, as far as i know the twin waste gate kit gives an customer better spool-up over a single waste gate manifold. I don't really understand yet what you mean with overkill.

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Thanks IanC,

What parts are needed to boost above 1,5 bar?

Will 264in/272ex or 272in/272ex in comparison with the 256in/264ex or 264in/264ex perform better or worse.

850cc to give me some headroom, will 1000cc work too or will an larger injector size give trouble during map sessions.

What does overkill mean? I'm actually amazed to hear that,:), can you please explain why, as far as i know the twin waste gate kit gives an customer better spool-up over a single waste gate manifold. I don't really understand yet what you mean with overkill.

 

Hi Mario,

 

1000cc injectors will be fine if you have a decent ecu like a Syvecs to control them. The twin wastegate design I sell will definately give you a faster spool up than single wastegate, in a back to back test I did against an HKS manifold our twin wastegate manifold improved spool up by nearly 1000rpm!

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Thanks for the info Paul, i'm very excited about this all and very much liking the the twin waste gate manifold, it's like an piece of art!

still need to decide on the cams, but want to know what longer durations cams (staggered)will do

in a set-up like this. Will they add spool time, will they add bhp, do they perform only in a certain rpm range?

I really want to know what the different options are before i buy something which i may regret in a later stadium.

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I would certainly go for Paul's twin WG manif.

 

Although I personally would go for 280 cams, my actual setup made nice results with 264 cams. On a stock engine, I guess 264 or 269 cams (SRD or Whifbitz stage 2) will be sufficient, as wilder cams will provide more punch in higher revs, which is not really what a stock engine likes.

 

Go for 1000+ injectors .. you never know what turbo is next on your shopping list. ;)

If you can afford, go for a fuel kit with bigger lines and rails. Check whifbitz pages for their latest products.

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Thanks for the info Paul, i'm very excited about this all and very much liking the the twin waste gate manifold, it's like an piece of art!

still need to decide on the cams, but want to know what longer durations cams (staggered)will do

in a set-up like this. Will they add spool time, will they add bhp, do they perform only in a certain rpm range?

I really want to know what the different options are before i buy something which i may regret in a later stadium.

 

Are you using a stock head or are you going to fit valve springs?

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The twin wastegate design I sell will definately give you a faster spool up than single wastegate, in a back to back test I did against an HKS manifold our twin wastegate manifold improved spool up by nearly 1000rpm!

 

What's the science behind that? The fastest spool you'll get is with a completely closed wastegate. So if your boost controller does it's job, it'll be shut until full boost is almost reached and then bang the wastegate open. From then on it pulses it to control boost pressure. I'm at a loss as to explain how having two completely shut wastegates affects spoolup by such a large amount compared to one completely shut wastegate.

 

Did you do your back to back test with a BC in place, or were you just feeding the wastegates with a boost reference and letting the spring do the work? Is there a fundamental design difference in the exhaust manifold to package the twin WG setup?

 

Regarding overkill, I always thought a twin 'gate setup was because your turbo system was so big, and the revs went so high (8000rpm+), one wastegate physically wasn't big enough to divert enough exhaust gas in order to control boost. So if you aren't running a massive turbo and a high rev limit, two wastegates would be overkill, like a twin fuel pump setup in a BPU car or a drag parachute on an NA.

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Thanks IanC,

What parts are needed to boost above 1,5 bar?

Will 264in/272ex or 272in/272ex in comparison with the 256in/264ex or 264in/264ex perform better or worse.

850cc to give me some headroom, will 1000cc work too or will an larger injector size give trouble during map sessions.

What does overkill mean? I'm actually amazed to hear that,:), can you please explain why, as far as i know the twin waste gate kit gives an customer better spool-up over a single waste gate manifold. I don't really understand yet what you mean with overkill.

 

There is no 100% correct answer to your questions, as it all depends on what your goal is. If you want a fast road car, then a T67 at 1.4bar will be great. Mild cam upgrades and fuel upgrades and a clutch keeps the costs down.

 

Once you go into the 272 cam territory you're losing more low down than you'll gain up top without raising the rev limit. Doing that starts to get expensive as you'll need to do something with the internals if you want any sort of longevity out of it.

 

1000cc is fine if you've got future plans to upgrade and an engine management system that can handle them ok. If you're only going for 500 to 600bhp on the T67 then they are, again, overkill.

 

I use 720cc injectors but my static fuel pressure is kind of low, so they are at their capacity at 1.4bar, maximum revs. I could up the fuel pressure to give them more headroom, but that would cock up my map, and I also don't think the single Walbro pump will be able to deliver much more fuel anyway. This is my point about what your goals are - if I wanted to go beyond where I am now, I'd probably have to replace the injectors, move to a twin pump setup, and probably change the clutch system. Then redo the whole map. All that just so I can have even less traction until 70mph? No thanks :) My goals were met a long time ago and I'm happy, if anything I'm looking for things that'll make more power lower down.

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What's the science behind that? The fastest spool you'll get is with a completely closed wastegate. So if your boost controller does it's job, it'll be shut until full boost is almost reached and then bang the wastegate open. From then on it pulses it to control boost pressure. I'm at a loss as to explain how having two completely shut wastegates affects spoolup by such a large amount compared to one completely shut wastegate.

 

Did you do your back to back test with a BC in place, or were you just feeding the wastegates with a boost reference and letting the spring do the work? Is there a fundamental design difference in the exhaust manifold to package the twin WG setup?

 

Regarding overkill, I always thought a twin 'gate setup was because your turbo system was so big, and the revs went so high (8000rpm+), one wastegate physically wasn't big enough to divert enough exhaust gas in order to control boost. So if you aren't running a massive turbo and a high rev limit, two wastegates would be overkill, like a twin fuel pump setup in a BPU car or a drag parachute on an NA.

 

I was wondering the same thing as I intend to use a GTX35R when I go single... However the cost of Pauls setup is very competitive compared to HKS units and similar quality I believe so that can be considered a major advantage.

 

Anyway, keen to see Pauls response..

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There is no 100% correct answer to your questions, as it all depends on what your goal is. If you want a fast road car, then a T67 at 1.4bar will be great. Mild cam upgrades and fuel upgrades and a clutch keeps the costs down.

 

Once you go into the 272 cam territory you're losing more low down than you'll gain up top without raising the rev limit. Doing that starts to get expensive as you'll need to do something with the internals if you want any sort of longevity out of it.

 

1000cc is fine if you've got future plans to upgrade and an engine management system that can handle them ok. If you're only going for 500 to 600bhp on the T67 then they are, again, overkill.

 

I use 720cc injectors but my static fuel pressure is kind of low, so they are at their capacity at 1.4bar, maximum revs. I could up the fuel pressure to give them more headroom, but that would cock up my map, and I also don't think the single Walbro pump will be able to deliver much more fuel anyway. This is my point about what your goals are - if I wanted to go beyond where I am now, I'd probably have to replace the injectors, move to a twin pump setup, and probably change the clutch system. Then redo the whole map. All that just so I can have even less traction until 70mph? No thanks :) My goals were met a long time ago and I'm happy, if anything I'm looking for things that'll make more power lower down.

Thanks for the explanation Ian, this is the best answer I received so far:,, Once you go into the 272 cam territory you're losing more low down than you'll gain up top without raising the rev limit’’, think i follow your advice on the cams, I would be stupid not to, i don’t want to mess up my stock motor.

I’ll stick to the staggered camshaft set-up like you said 256in/264ex, will have a chat with Lee in the near future and ask if he can do these cams in the hollow billet version. So I can also enjoy the weight savings on the rotating mass.

I get your point now what you mean with overkill, lol:)‘’drag chute on an NA supra’’.

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Yes, i was thinking about an supertech or BC valve spring and retainer kit, for the rest stock motor and stock head.

 

If your going with the upgraded valve springs I would go with my 280 9.9 lift cams, we did a test back to back against HKS 280 cams and we not only gained 70bhp we also gained 200rpm of spool up to!

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What's the science behind that? The fastest spool you'll get is with a completely closed wastegate. So if your boost controller does it's job, it'll be shut until full boost is almost reached and then bang the wastegate open. From then on it pulses it to control boost pressure. I'm at a loss as to explain how having two completely shut wastegates affects spoolup by such a large amount compared to one completely shut wastegate.

 

Did you do your back to back test with a BC in place, or were you just feeding the wastegates with a boost reference and letting the spring do the work? Is there a fundamental design difference in the exhaust manifold to package the twin WG setup?

 

Regarding overkill, I always thought a twin 'gate setup was because your turbo system was so big, and the revs went so high (8000rpm+), one wastegate physically wasn't big enough to divert enough exhaust gas in order to control boost. So if you aren't running a massive turbo and a high rev limit, two wastegates would be overkill, like a twin fuel pump setup in a BPU car or a drag parachute on an NA.

 

There is a good article here http://www.modified.com/tech/modp-0906-twin-scroll-turbo-system-design/viewall.html

 

We first did a test with one of my single wastegate manifolds and that improved spool up by about 800rpm over the HKS manifold. Then I changed the single wastegate version to one of my twin wastegate versions and saw another 200-300rpm improvement. Manifold is exactly the same apart from the wastegate routing obviously, dont ask me why it works but it does! All tests were done with the Syvecs controlling the boost with no adjustments made.

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If your going with the upgraded valve springs I would go with my 280 9.9 lift cams, we did a test back to back against HKS 280 cams and we not only gained 70bhp we also gained 200rpm of spool up to!

 

Thanks for the input Paul! nice article too,

maybe i should've been more specific in first place, i just wan't some input on cam decission etc. due i'm not experienced enough to decide what camshaft option will be giving best hp/torque figures in a set-up with an 67mmdbb.

I don't want to leave an handfull of bhp on the table if i can make a decent decission which is widely proved/tested by owners which have had some similar set-up.

I don't want to break my motor, by going to high a duration and lift on the cams which maybe isn't good for the GTE's stock internals.

If it's guaranteed that my engine will hold together for let's say a year from when the single conversion is completed, i then can concentrate on improving the bottom end the year after.

The question about the injector size has to do with future plans, eg. an gtx74mmdbb turbocharger for example, let's say if i choose to go with 850cc injectors, will they be at their end for an upgrade towards an gtx74mmdbb? Hence my question about if it is possible to overdesign the injectors on my set-up, just so i won't have to deal with installation and replacementcosts again.

But how wlll those 280's perform against 256in/264ex, are there any dyno sheets or comparison charts available, so i can see in what rpm range the improvement of the cams is noticable, my redline is also stock and i don't know if the redline can be changed towards lets say 7200 in completely stock condition.

Thanks,

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Best stage 1 cams are GSC S1 with their beehive springs.

Yanks think its the best street cam available. they give more hp and tq then hks 272's.

The GSC S1 use 269 btw and have a pretty aggresive lift and require adjustable cams if you dont like the lope they provide when untuned.

 

http://www.power-division.com/home.php?cat=345

http://www.power-division.com/home.php?cat=346

 

and ofcourse the test from USA:

http://www.supraforums.com/forum/showthread.php?533317-Camshaft-test-GSC-S1-and-S2-vs-HKS-272

 

I dont know if the GSC cams are interference tho, titan 264's are the only ones to my knowledge that not seem to make a 2jzgte non vvti interference

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There is a good article here http://www.modified.com/tech/modp-0906-twin-scroll-turbo-system-design/viewall.html

 

We first did a test with one of my single wastegate manifolds and that improved spool up by about 800rpm over the HKS manifold. Then I changed the single wastegate version to one of my twin wastegate versions and saw another 200-300rpm improvement. Manifold is exactly the same apart from the wastegate routing obviously, dont ask me why it works but it does! All tests were done with the Syvecs controlling the boost with no adjustments made.

 

Ah, right, all that explains things. I'm assuming your single wastegate manifold is a divided housing type and the HKS isn't? When run in conjunction with a proper twin scroll turbo housing, it certainly should deliver improvements like you say. From that article, it looks like the twin wastegate setup is really just a factor of having a divided housing, and twin wastegates allow the collector part of the exhaust to be a more efficient design.

 

Really it's the twin scroll turbo mounted on a divided housing manifold that delivers all the performance improvements. The twin wastegate setup is just a byproduct of this design :) Your first post read like simply adding a second wastegate to an existing setup would magically improve spool, hence my questions :D

 

All this gets me thinking. Some of the newer DBB turbos, like these batmowheels and BW and especially the new Garretts, have improved spool times. If you ran one of those with a twin scroll housing on a divided manifold like these, at about 1.5bar, with the smallest a/r you could get away with, just how damn fast would they spin up?

 

-Ian

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So I've been idly looking at the GTX3582R compressor maps against a Supra, thinking "just how fast can we get a 550+bhp Supra on boost"? I've attached my findings, but I'm never too sure about compressor maps so see what you think. I went for 1.4bar delivering 61lbs/min of air (around 600bhp) at peak power.

 

If I've done this right, then the top end is good, as it's still 75% efficient. The torque peak of 5000rpm is bang on the highest efficiency island :thumbs:

 

It's only when you get low down things might become a problem. If it hits 1.4bar of boost by 3500rpm then it's at 65% efficiancy and quite close to the surge line. I plotted 1.4bar at 3000rpm and it's well into surge, but I think that might be an optimistic level of spool anyway :) I did 1bar at 3500 and it's still just about hanging in there, so if the boost builds up through 3000 to 3500rpm it'd work. But as the point of this exercise is "can we get a faster spool up from the latest DBB turbos and manifolds etc.?", it's not much use if the turbo stalls when it spins up faster than my current T67DBB!

 

My old graphs from testing the T67DBB shows I can get 1bar in 6th at 3300rpm, so if the GTX3582R spools up faster than this, chances are it'll surge if you give it loads of boost in a tall gear. Mind you, 3rd hits 1bar at 4000rpm, so these gears would be where you feel the benefit I suppose.

 

I've basically confused myself, and I'm happy to share that :D

 

-Ian

GTX3582Rcomp - supra.jpg

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