which turbo size should i go with?

[2000gts2000]

if you had mahle low compression pistons, along with other little engine mods like main bearings and rod bearings, which size turbo should you go with? i had a certain turbo in mind, but i saw that someone else is running the same turbo on stock internals and talking about it like it was a perfect fit, which makes me think that i need a bigger one. what size would you guys go with?

[Boosted2.0]

what are your power and performance goals. What kit are you using. What is your intended usage (street, drag, road race, autox etc)

[2000gts2000]

I'm considering a custom kit with a Neukin manifold and downpipe, and I'm looking for as much power as i can safely get. I want at least 300whp, if i can get more, i'd like to go for it. and with low boost settings it's a daily driver, with a higher boost setting i'd like to drag race it. boosted, i know you're the professional here, so any knowledge you'd like to share with me would be great.

[Boosted2.0]

If you go with Mahle pistons and MWR bearings MWR oil pump, ARP main studs and an otherwise stock setup then you could easily hit 300 and probably push as far as 400 HP without breaking a huge sweat if you choose the right turbo. (obviously you will need fueling system, ecu, etc as well.

But as always safe is only as safe as your tune and your tuner.

As for what turbo, for street and drag in the 300+ WHP range you probably want to look at the GT30R or larger. Smaays kit would also be a great solution and require less engineering on your part.

[monkeywrench]

If you go with Mahle pistons and MWR bearings MWR oil pump, ARP main studs and an otherwise stock setup then you could easily hit 300 and probably push as far as 400 HP without breaking a huge sweat if you choose the right turbo. (obviously you will need fueling system, ecu, etc as well.

But as always safe is only as safe as your tune and your tuner.

As for what turbo, for street and drag in the 300+ WHP range you probably want to look at the GT30R or larger. Smaays kit would also be a great solution and require less engineering on your part.

If you'll be dropping compression the 30R is a great choice. Spools reasonably well and made 550whp in our red car.

[2000gts2000]

alright, well i went to www.turbobygarrett.com and there are 4 different gt30 turbos, 3 are gt3071r and the 4th was a gt3076r. what's the difference between the four? thanks for all your help.

[Boosted2.0]

alright, well i went to www.turbobygarrett.com and there are 4 different gt30 turbos, 3 are gt3071r and the 4th was a gt3076r. what's the difference between the four? thanks for all your help.


Depends on if you want interal or external WG etc.

[2000gts2000]

oh, ok. But if it were up to you, which of the four would you go with? The 4 they had listed were:
GT30
GT3071R
GT3071R - 700382-3
GT3071R - 700382-20
GT3076R - 700382-12
I'm sure someone with your experience with cars has seen this page a million times, but if you want to see the exact page itself you can see it here. http://www.turbobygarrett.com/turbobygarrett/products/turbochargers.html
Im planning on going with an external waste gate, but as far as performance, which is the best here?
Thanks for your help.

[Smaay]

i can build you a turbo system with teh GT30R. i just finished one on another members car.

[Boosted2.0]

Then you just need a GT3071R with a turbine housing designed for an xternal gate - all the ones pictures in that thread are internal gate

i can build you a turbo system with teh GT30R. i just finished one on another members car.


even better

[Jesse IL]

I'd use none of those turbos or that manifold.

I'd use a GT2871R, 56 trim model. Buy the turbo, send it to Smaay and have him build you an internal wastegate version of his manifold with a T25 flange and a corresponding downpipe. He should have all the necessary jigging to make that happen, plus he can provide you with the rest of the kit and the fuel system.

About the Mahle pistons, don't assume you can use those on an old block. You need measurements of your block to know if they'll work. If your block needs to be sleeved, I'd go with the Wisecos since they're lighter. You could even go with a custom compression ratio like I did to give you some power back and make the car more streetable. IMO, a Stage 3 shortblock from MWR is your best answer.

[monkeywrench]

The 3076 is the one commonly called the "GT30R". The others are the Gt3071 which has a smaller compressor and also has the T25 size flange and an internal wastegate (doesn't flow enough to control boost below 10psi). We've made over 400whp on a 3071 without a problem.

[2000gts2000]

I'd use none of those turbos or that manifold.

I'd use a GT2871R, 56 trim model. Buy the turbo, send it to Smaay and have him build you an internal wastegate version of his manifold with a T25 flange and a corresponding downpipe. He should have all the necessary jigging to make that happen, plus he can provide you with the rest of the kit and the fuel system.

What's wrong with the neukin manifold? I'm in no way putting down smaay's kit, but i thought the tubular design of the neukin manifold was made especially for extra performance. In the end, which manifold will get better performance, smaay's kit, or a custom kit with the neukin manifold?

About the Mahle pistons, don't assume you can use those on an old block. You need measurements of your block to know if they'll work.

yes, of course. I've read the posts and have spoken to the guys at MWR. From what i understand, i need to measure the bores and the pistons, and that if the cylinder walls aren't right for the pistons then you already had a problem with your engine block before you even bought the pistons. According to the conversation i had with the guys at MWR, the problem of not having the cylinders match up to the size of the pistons stems from the age of the engine, and that excessive miles tends to warp the cylinders, but i only have like 40,000 miles on my engine, and that should still be in good enough condition for the pistons, right? or did i completely misunderstand the conversation i had with the guys at MWR?

[Jesse IL]

What's wrong with the neukin manifold? I'm in no way putting down smaay's kit, but i thought the tubular design of the neukin manifold was made especially for extra performance. In the end, which manifold will get better performance, smaay's kit, or a custom kit with the neukin manifold?
1. The Neukin manifold has never been shown to be superior to the manifolds being used on other cars.
2. The Neukin manifold is designed for an external wastegate and T3 flange, which means the smallest turbo you can run is a GT3076R. This is a big, laggy turbo. If you're building a drag car, it will be fine but I personally don't think its a great street turbo. The fact that I know you've never driven a turbo Celica means that I know you're basing your decision 100% on internet dyno charts rather than on driving cars.
3. The extremely large size makes fitment difficult.
4. Its not part of any kit, so you're going to have to go custom on anything.
the problem of not having the cylinders match up to the size of the pistons stems from the age of the engine, and that excessive miles tends to warp the cylinders, but i only have like 40,000 miles on my engine, and that should still be in good enough condition for the pistons, right? or did i completely misunderstand the conversation i had with the guys at MWR?

You're making a BIG assumption, which is why I have a problem with it. You're also taking the word of mouth of MWR and have weak technical understanding yourself. I would only be comfortable with the Mahles if I didn't care about my car being down potentially for an extended time and had a second car to drive (you should always have two cars if you want to turbo a Celica). If you tear down your engine and have the bores measured, you could end up dead in the water and be down for an extended period of time. If you want to go with the Mahle pistons, I'd price out a new main block from Toyota and be prepared to buy it if your measurements are off.

[2000gts2000]

If you tear down your engine and have the bores measured, you could end up dead in the water and be down for an extended period of time. If you want to go with the Mahle pistons, I'd price out a new main block from Toyota and be prepared to buy it if your measurements are off.

ok, well lets say that my engine, which is running completely fine with the stock pistons and bores right now, ends up having the problem of bad bore sizes for the mahle pistons. If it turns out that i can't use the mahle pistons, what's to stop me from putting the stock pistons back in and just using them since they were running fine to begin with? why would i be down for an extended period of time?

I admit the fact that i'm not really knowledgeable on the mechanical stuff on the celica, but the guys at MWR are. Now, they said over the phone that the mahle pistons wouldn't fit in the case that my cylinders are warped due to the extreme use/old age of the engine. Now, my car is going on 8 years old and only has 40,000 miles. I baby it, and it performs like a dream. Now unless they lied to me, or neglected to tell me other pertinent information, the information that i've gathered would lead me to believe that the stock size mahle pistons will fit. But, even if they don't, i can just go back to the stock pistons. Is there something else that they didn't tell me as to why it wouldn't work?

[Smaay]

my philosophy is that if you ever crack the block open or any surface where bearings are involved, I replace them. you can actually pull the motor, take off teh head, and measure the bores. just rotate the pistons to BDC

[Jesse IL]

ok, well lets say that my engine, which is running completely fine with the stock pistons and bores right now, ends up having the problem of bad bore sizes for the mahle pistons. If it turns out that i can't use the mahle pistons, what's to stop me from putting the stock pistons back in and just using them since they were running fine to begin with? why would i be down for an extended period of time?
The stock pistons are pieces of crap and will likely fracture given your power goals.
I admit the fact that i'm not really knowledgeable on the mechanical stuff on the celica, but the guys at MWR are. Now, they said over the phone that the mahle pistons wouldn't fit in the case that my cylinders are warped due to the extreme use/old age of the engine. Now, my car is going on 8 years old and only has 40,000 miles. I baby it, and it performs like a dream. Now unless they lied to me, or neglected to tell me other pertinent information, the information that i've gathered would lead me to believe that the stock size mahle pistons will fit.
Who are you going to believe, the guys who are trying to sell you parts or the numerous people on this forum who have taken apart old engines and had the Mahle pistons not work? I'm not saying they won't work, but if they don't, you're up shiet creek without a paddle.

Its not that MWR doesn't know what they're talking about, its that you NEED to have a definite answer to a question that has no definite answer. I've told you this before, but you're never satisfied with any answer unless you can get some iron-clad guarantee that the decision you're making is 100% the best answer possible and there's no way it could go wrong. The problem is that you're forcing MWR to give you an answer that they really can't answer. Should the pistons work if you baby the car (according to you) and it only has 40k miles? Sure, but then again they might not. You don't seem to have any contingency plan for that scenario.

Frankly, I think you should drop the idea of turboing your car altogether. If you want a turbo car, buy an EVO or STI. As someone who owns a F/I Celica, my personal feeling is that someone with zero mechanical knowledge (by your own admission) should ever own one. They are inherently unreliable, require extensive custom tuning and in general are bad cars for your everyday car enthusiast. If you want a F/I Celica, you NEED a beater car (which you don't have) because your car WILL go down (which you seem unwilling/unable to accept) and the build/tune process tends to be long and involves the car being out of comission. You can tell me I'm wrong, but I could easily come up with a dozen threads from guys like you about their year plus builds that got stupidly expensive and where they got marginal results. I mean, you debated for months the purchase of some $20 motor mount inserts. What are you going to do when it comes to forking over thousands for turbo parts?

[blownoffvalve]

it would be easy to go with a full complete kit with thosee upgrades