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Discussion Starter #1
Since there are existing aftermarket Garrett flanged manifolds for Duratec 2.3s, I was wondering if Mazda changed anything on our exhaust that would prevent us from using a Duratec 2.3 turbo manifold.


Anyone in a dealer environment able to compare exhaust manifold gaskets?

If not, I guess I can order the gaskets and compare them.
 

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the block is the same for sure, but there might be a new divet/hole/post somewhere in the mix to make it not fit perfectly?
 

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I want to keep my DISI head and put a diferent manifold on it. If the ports are the same as the Duratec 2.3 I can use an existing Garrett flanged manifold rather than have one custom made.

I think you could put a GT2871R on and get boost in at nearly the same RPM and pull hard to 6800 for a peak of about 390ish HP at the crank using the stock boost levels. The compressor would be running at 75-76% efficiency for the meat of the power band too.

That would make for a fun ride.
 

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I want to keep my DISI head and put a diferent manifold on it. If the ports are the same as the Duratec 2.3 I can use an existing Garrett flanged manifold rather than have one custom made.

I think you could put a GT2871R on and get boost in at nearly the same RPM and pull hard to 6800 for a peak of about 390ish HP at the crank using the stock boost levels. The compressor would be running at 75-76% efficiency for the meat of the power band too.

That would make for a fun ride.
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dont know about getting boost at 2500rpm with the GT2871R. you'll have to have a tb exhaust for sure in order to even come close to spooling up down there. but you'll have a ton more top end.
 

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Think you'll need to tweak the ECU. There's a rumour that the ECU closes the throttle opening to 80% when u hit 6000rpm.
 

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Discussion Starter #6
dont know about getting boost at 2500rpm with the GT2871R. you'll have to have a tb exhaust for sure in order to even come close to spooling up down there. but you'll have a ton more top end.
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You'd have to come up with a new downpipe to fit the Garrett so it would be a good time to go 3".

Think you'll need to tweak the ECU. There's a rumour that the ECU closes the throttle opening to 80% when u hit 6000rpm.
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I'll do some logging with AutoEnginuity and see what the actual TPS is over 6k.
 

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Since there are existing aftermarket Garrett flanged manifolds for Duratec 2.3s, I was wondering if Mazda changed anything on our exhaust that would prevent us from using a Duratec 2.3 turbo manifold.
Anyone in a dealer environment able to compare exhaust manifold gaskets?

If not, I guess I can order the gaskets and compare them.
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No, they're not even close. Totally different bolt pattern. The DSI is all by itself, CX7 and MPS6 only.
 

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Discussion Starter #8
No, they're not even close. Totally different bolt pattern. The DSI is all by itself, CX7 and MPS6 only.
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Thanks!

I guess it will require a custom job.
 

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Thanks!

I guess it will require a custom job.
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Although the basic architecture of the engine is the same as the regular 2.3 there are some fairly signifigant differences in the cylinder head casting to accomodate the DSI and turbo. I almost wonder if you were looking to modify to the point of a max output race type application where peak horsepower was the goal if you might not be better off ditching the DSI altogether and going back to the regular setup. Pure speculation on my part but it seems to me that, although the DSI does a REALLY good job providing low end and midrange performance and driveability, it may end up being a liability if you're looking for maximum power levels. Of course that would defeat the whole purpose of the design paramaters, but if you're looking for max power.........
Then again, if you look at Audi's current V12 Turbo diesel setup with over 800 ft lb's of torque and 600 plus hp using DIESEL fuel it kind of leads you to believe that there's a tremendous amount of headroom in this design. Now HERE'S an idea for the aftermarket, how about a DIESEL upgrade kit? Heck, all you'd have to do would be to put a set of pistons in it to bump up the compression about 8 or 9 points and throw away the ignition system and it would BE a diesel, wouldn't it?
 

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Discussion Starter #10
Although the basic architecture of the engine is the same as the regular 2.3 there are some fairly signifigant differences in the cylinder head casting to accomodate the DSI and turbo. I almost wonder if you were looking to modify to the point of a max output race type application where peak horsepower was the goal if you might not be better off ditching the DSI altogether and going back to the regular setup. Pure speculation on my part but it seems to me that, although the DSI does a REALLY good job providing low end and midrange performance and driveability, it may end up being a liability if you're looking for maximum power levels. Of course that would defeat the whole purpose of the design paramaters, but if you're looking for max power.........
Then again, if you look at Audi's current V12 Turbo diesel setup with over 800 ft lb's of torque and 600 plus hp using DIESEL fuel it kind of leads you to believe that there's a tremendous amount of headroom in this design. Now HERE'S an idea for the aftermarket, how about a DIESEL upgrade kit? Heck, all you'd have to do would be to put a set of pistons in it to bump up the compression about 8 or 9 points and throw away the ignition system and it would BE a diesel, wouldn't it?
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My goal was to swap out the turbo for a Garrett ball bearing design with enough flow potential to carry 15.5 PSI to 6800 redline.

That, in theory haha, would keep you within the factory fuel and spark table boundaries. I'd prefer to not have to mess with supplemental fuel control systems. J2534 pass-thru programmers are $500 or less now. Eventually the fuel and spark table offsets within the flash files will become known allowing custom tuning of the factory ecu.

I would like to keep the DISI for low end torque to get the turbo spooled early. That and the ball bearing design of the Garrett should get the boost in by 3k or less on the GT2871R.

I don't want a race car. I just would like to get the full potential out of the engine it came with.

I think you could get the custom manifold, turbo and plumbing for $2.5k-ish.
 

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My goal was to swap out the turbo for a Garrett ball bearing design with enough flow potential to carry 15.5 PSI to 6800 redline.

That, in theory haha, would keep you within the factory fuel and spark table boundaries. I'd prefer to not have to mess with supplemental fuel control systems. J2534 pass-thru programmers are $500 or less now. Eventually the fuel and spark table offsets within the flash files will become known allowing custom tuning of the factory ecu.

I would like to keep the DISI for low end torque to get the turbo spooled early. That and the ball bearing design of the Garrett should get the boost in by 3k or less on the GT2871R.

I don't want a race car. I just would like to get the full potential out of the engine it came with.


I think you could get the custom manifold, turbo and plumbing for $2.5k-ish.
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I don't consider myself to be an expert in these matters and this is just my opinion but I think if you want to have your cake and eat it too here (keep the bottom end and gain more top end) the ideal solution would be to go with a variable vane turbo setup. Unless I miss my guess the Mazda engineers were well aware of this option but production cost considerations ruled it out. While the direct injection is part of the reason why we have our beloved bottom end punch I believe by far the biggest part of that package is the small turbo because it spools up so quickly. Lose that and there goes the bottom end. Again, just opinion without the testing to back it up but I'd be willing to gamble on it.
The biggest thing to remember here is that it IS a package, all of the components are inter-related, change one and you change everything. Another large part of the equation is the higher than normal compression ratio facilitated by the better atomization and charge cooling properties of the direct injection.
 

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You might also consider looking into an adapter flange to bolt between and the stock one and the new turbo. Its not the most elegant solution, but can work well.
 
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