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Discussion Starter · #1 ·
I'm trying to decide between a custom hot side supercharger setup and an MWR turbo. The appeal of the SC is the project somewhat, but mostly the "throttle response" type spool time.

If you have an MWR turbo kit on your 1ZZ spyder:

1.) if you are rolling along at around 4k rpm and then go to wide open throttle, how long before it builds full boost?

2.) If you are on it hard (WOT), say maybe around 4k rpm again, and lift off for a couple seconds, when you get back on it, how long before it rebuilds full boost?

3.) what are you using for a boost controller to get the above results?

Thanks in advance for the feedback!
 

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Not considering a Rotrex supercharger?

What racing class would allow aftermarket forced induction?
 

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Discussion Starter · #3 · (Edited)
Not considering a Rotrex supercharger?

What racing class would allow aftermarket forced induction?
Not really. The car will heat soak pretty badly sitting in grid. Meth injection isn't allowed in any class unless it is factory installed. I want intercooling. I want area under the curve. Basically I want 200 ft-lb of torque or so from 3500 or so to 7000 or so.


The two relevant classes are SSM and XP.
 

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I have never really had any noticeable lag on a 1zz or 2zz turbo.

For autox I would look at something like a turbokits.com with a short barrel style A/W intercooler in the intake piping. This will reduce any kind of lag and you can put ice in a reservior tank in the frunk. Regardless of how hot the ambient temperature you will have cold Air intake temperatures until the water temperature rises

You could run a similar intercooler setup with a rotrex.

Problem with Autox will be airflow to any A/A intercooler in the rear of the car. There are not a lot of long straights in autox. Unless you put a big fan on the intercooler it may heat soak with run after run.
 

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I agree with silversprint. The shorter the route from the turbo to the throttle body, the less lag you'll have. Also with an A2W cooler and a reservoir, you can fill with ice between runs to keep it cooler. Put a petcock on the bottom of the reservoir so you can easily drain excess water out.
 

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Discussion Starter · #6 ·
I don't think I'm interested in the log manifold and Chinese garret knock off journal bearing turbo of the turbo kits setup. I do plan to do water to air intercooling internal to the plumbing from the compressor to the throttle body, if I do this.

SS, I've driven NB's with ball bearing GT28 turbos, and found in the situations in my first post, the turbo is providing some boost as soon as you are back on the gas, but it takes maybe 8/10 of a second to get back to near full boost (longer at lower RPM). If my calcs are correct, the SC I want to use will have full boost within 0.25 seconds of WOT at any RPM. That is a huge difference when most of the places where you can go WOT are less than 1 second long. I'm lead to believe some of the problem is manual boost controllers that start bleeding the waste gate well below setpoint. Thoughts on this? Can I really get to a setup with a turbo where I can lift off the gas, apply some input for a second or two, then get back on it and have full boost in under half a second?

I should have never driven that vette......
 

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The shorter the route from the turbo to the throttle body, the less lag you'll have.
Assuming you don't need an intercooler (street and light track use), would that not make the injection setup superior to an intercooler then? i.e. not having to route the intake through the intercooler and all the associated tubing?
 

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Assuming you don't need an intercooler (street and light track use), would that not make the injection setup superior to an intercooler then? i.e. not having to route the intake through the intercooler and all the associated tubing?
With a barrel type A2W setup, you can usually replace a straight section of intake piping with the cooler, so the system isn't any longer than without it. With an A2A cooler, you easily have a few feet extra piping. As for meth injection, I like the idea of it as an additional system to cool IATs but wouldn't want to solely rely on it.
 

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Not really. The car will heat soak pretty badly sitting in grid. Meth injection isn't allowed in any class unless it is factory installed. I want intercooling. I want area under the curve. Basically I want 200 ft-lb of torque or so from 3500 or so to 7000 or so.


The two relevant classes are SSM and XP.
And EM.
 

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Our manifold isn't quite a log, it is a semi tubular with short runners. The shortness of the manifold will actually allow for more heat to the turbo and faster boost response. Our turbos aren't a knock off. We have our own bearing housing with journal bearings and 360 degree thrust, we use our own billet compressor wheel and our new batch of turbos will have a larger internal wastegate port to allow for even better boost control. Our turbos are made from quality metal & parts, they are component balanced and then assembled, spec'd and high speed VSR balanced up and over 100,000 RPMs with full oil pressure. They are then hooked up to a water pressure jig to test the internal water chambers. Now, I can completely understand someone not wanting to run a turbo they have not had experience with, fair enough. So you can always upgrade to the Garrett GT28RS or in your case (depending on HP goals) I might suggest the GT2560R and a .64ar housing for the ultimate in boost response. Couple that with our short charge piping and full 3" exhaust and you would have a very potent track machine :)







I don't think I'm interested in the log manifold and garret knock off journal bearing turbo of the turbo kits setup. I do plan to do water to air intercooling internal to the plumbing from the compressor to the throttle body, if I do this.
 

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Discussion Starter · #11 ·
Now, I can completely understand someone not wanting to run a turbo they have not had experience with, fair enough. So you can always upgrade to the Garrett GT28RS or in your case (depending on HP goals) I might suggest the GT2560R and a .64ar housing for the ultimate in boost response. Couple that with our short charge piping and full 3" exhaust and you would have a very potent track machine :)
Those photos change my understanding of your manifold design; thanks for posting them!

Priority number one is throttle response. I want to be able to come off the throttle completely for a couple seconds at 4k rpm (after having been at full boost WOT), and have not just boost, but nearly full boost nearly immediately on WOT. This is possible with a positive displacement supercharger.... I've looked at the GT2560R 60 trim 0.60ar, and I'm unclear on whether it can handle the low pressure ratio at peak flow rate for 250 HP or so. At best it seems to be getting ready to lose a ton of thermal efficiency and start spinning like crazy at that part of the map. The 0.64ar seems like it would be worse on thermal efficiency at the top end of the flow numbers I want. What I can't get my head around yet is by how much and if it matters to me. The sure to work answer is the GT28RS, but I'm not sure the response time will make it worth having for my application. Thoughts?

I have a racing buddy who has a dyno in his shop, so tuning shouldn't be a problem. I plan to run a custom intercooler setup that has high thermal efficiency and relatively low air volume. I want to get near 200 ft-lb by 4000rpm, near 200 ft-lb at 6800, and hopefully a little north of that in between. I want to not do damage running out to 7200 rpm or so, even if it means dumping the fuel to it and losing power up there, or something like that. And I want reliability, so I want a reasonably sized external waste gate to go along with the tuning time, cool charge air, and knock response system.
 

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Go with GT2560 .64AR and external dump wastegate if possible. You will get 200 ft-lb around 3000rpm. I am almost certain response at 4000 rpm is less than .5 sec if you're in 2nd or 3rd gear (which should be used most in autox), and pretty much instant response pass 5000rpm. Make sure your downpipe and exhaust is at least 3" and small/short intercooler pipings. Use Tial wastegate and BOV to guarantee no leak for even faster response.
 

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I concur with ThangCu35, the GT2560 would be beautiful for your goals. I bet you can get to your goals with an internal gate to help keep the cost down as well. The GT2560 would require welding to the comp housing in order for a coupler style attachment, but we can do that easily here so it is a drop in on our kit. The GT2560 would spool very fast, in the low 2Ks, torque should be ~200Ft Lbs and HP easily at the 250 mark. That turbo with our tight manifold and charge piping (add some thermal coating to get the heat to the turbo faster) and I think you have a winner. Hope this helps. Thanks

Those photos change my understanding of your manifold design; thanks for posting them!

Priority number one is throttle response. I want to be able to come off the throttle completely for a couple seconds at 4k rpm (after having been at full boost WOT), and have not just boost, but nearly full boost nearly immediately on WOT. This is possible with a positive displacement supercharger.... I've looked at the GT2560R 60 trim 0.60ar, and I'm unclear on whether it can handle the low pressure ratio at peak flow rate for 250 HP or so. At best it seems to be getting ready to lose a ton of thermal efficiency and start spinning like crazy at that part of the map. The 0.64ar seems like it would be worse on thermal efficiency at the top end of the flow numbers I want. What I can't get my head around yet is by how much and if it matters to me. The sure to work answer is the GT28RS, but I'm not sure the response time will make it worth having for my application. Thoughts?

I have a racing buddy who has a dyno in his shop, so tuning shouldn't be a problem. I plan to run a custom intercooler setup that has high thermal efficiency and relatively low air volume. I want to get near 200 ft-lb by 4000rpm, near 200 ft-lb at 6800, and hopefully a little north of that in between. I want to not do damage running out to 7200 rpm or so, even if it means dumping the fuel to it and losing power up there, or something like that. And I want reliability, so I want a reasonably sized external waste gate to go along with the tuning time, cool charge air, and knock response system.
Go with GT2560 .64AR and external dump wastegate if possible. You will get 200 ft-lb around 3000rpm. I am almost certain response at 4000 rpm is less than .5 sec if you're in 2nd or 3rd gear (which should be used most in autox), and pretty much instant response pass 5000rpm. Make sure your downpipe and exhaust is at least 3" and small/short intercooler pipings. Use Tial wastegate and BOV to guarantee no leak for even faster response.
 

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Does anyone have a dyno comparison of a GT28RS and GT2560 turbo'd 1ZZ? Is the latter a no-brainer if not planning to make excessive HP?
 

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Discussion Starter · #15 ·
Does anyone have a dyno comparison of a GT28RS and GT2560 turbo'd 1ZZ? Is the latter a no-brainer if not planning to make excessive HP?
I don't have what you ask for for Dyno plots, but I have a lot more first hand experience than when I started this thread. As was the origin of this thread (and probably why you posted here?) there is more to it than Dyno plots. My (possibly minority/unpopular) opinion is that the 2560 is, as others told m right here in this thread before I bought one, a better option than the GT28RS if you don't plan to build the engine.

The GT28RS is potentially both more thermally efficient and more pressure efficient (depending on A/R) at higher rpm, while the 2560 builds boost sooner and responds to transients quicker. On a Dyno plot this will show as the 2560 having more power at very low rpm, and a little less at higher rpm. I'm not entirely satisfied with my 2560 (on my miata), but compared with an otherwise similar miata with a gt28rs, it is the better choice both on the autocross course and anytime fun without timing is the goal (given no internal mods to support more boost). This is based on the miata 1.8 at 13.5 psi.

The miata was a great purchase. It quickly taught me 3 things I thought I already knew: 1.) I'm too picky / perfectionist to buy someone else's project. 2.) when it comes to power, there is no such thing as enough, but more shouldn't come at the expense of responsiveness. 3.) budget builds need near constant attention, which is ok on the miata, but wouldn't make me happy on the spyder.
 

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I'm trying to decide between a custom hot side supercharger setup and an MWR turbo. The appeal of the SC is the project somewhat, but mostly the "throttle response" type spool time.

If you have an MWR turbo kit on your 1ZZ spyder:

1.) if you are rolling along at around 4k rpm and then go to wide open throttle, how long before it builds full boost?

2.) If you are on it hard (WOT), say maybe around 4k rpm again, and lift off for a couple seconds, when you get back on it, how long before it rebuilds full boost?

3.) what are you using for a boost controller to get the above results?

Thanks in advance for the feedback!
I had a built 1zz with a MWR turbokit.
never had problem with any turbo lag and the response was good, alwas had a good amount of power at around 3k,

I used a Greddy Prospec II for boost control, it is a little bit hard to get used to but works great, and U have the chance to have 3 diffrent setups, base boost, and to saved ones, i think the base was a 0,7bar, then my other ones was a 1,0bar and 1,3bar. and as mentioned. worked great!

how quick it will spool dippends a little, what turbo are you going to use? I have the GT28RS for my setup.
 

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Discussion Starter · #18 ·
Thanks for that. So which route will you be taking with your Spyder?
There are several possibilities in the running still. I don't have to decide until this off season :D The smart choice for me would probably be a GT2554 on a short, thin walled header with a reasonable merge collector. right now I'm back to considering adding a whole bunch of weight in the name of reliability (bigger displacement rather than forced induction).
 

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One thing to consider if partial throttle modulation and building boost fast are high priorities is to not run a bov. This will allow excellent part throttle modulation, and throttle response, because you aren't dumping boost and starting at zero pressure every time you lift on the throttle. Keeping some pressure in the charge pipe will allow you to build boost back up exponentially faster than a bov set up.
 

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^ wrong, you will actually build boost even slower between shifts, because the excessive pressure will be redirected back at the compressor blade, stalling it, and create compressor "surge", which will exponentially destroy your turbo in no time. The excessive pressure will find its way out of the charge pipe no matter what, either through the compressor housing or blow up a coupler. A more reasonable approach is a bypass valve to redirect airflow to inlet of turbo. The goal is to keep the compressor blade from slowing down much, by allowing the air flow to keep moving in the positive direction, and that's what the BOV and BPV are for.
 
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