evomind

ive been told bb turbos only spool up a few hundred rpm faster than stock......

chuntington101

MalibuJack that was such a good post. Mate, don’t worry to much about what us brits have coz now some of you have seen what can be done, and the fact that the vendors will want to make money, there will be stuff out soon. That is if the vendors are actually reading these threads and seeing what people want!!!!!!

And on the whole BIG turbo v. stock turbo, I am so board with reading “I got a huge turbo and I’m still only running 400bhp”. Talk about a waste of money, read what you are putting, that’s a waste of a good turbo!

Power is good and we all strive to get more. But if you where to bring your car with its big turbo over here and run down some of our B-roads against EVO 400 car with a modded stock turbo then I will guaranty you will loose. The same will apply at the track. Most racers hate turbo engines because of the un-linier power delivery, so bolting a bigger turbo on is only going to make things worse.

On the boost thing, a Ti turbo with a GOOD bb conversion will run at 2.4 bar no problems in the midrange. This will give you loads of torque where you need it (not at 5K+), and it torque that does the accelerating.

Please forget spool up for a minute. If driven properly then you can get into the correct rev range anyway (although you have a lower spooling point on the bb turbo). The thing that you will notice is LAG. This is the turbos down fall. No matter what you do (bbs, increasing cc, high lift cams, etc, etc) as you hit the throttle again the turbo still has to speed up. This takes time, bigger turbos take longer (on same cc), smaller turbos take less time!

Thanks Chris.

Captain EVO

So like I isaid, its all about spool baby. Give me my stock turbo with the BB/Ti conversion. That is the ultimate. The rest are just dyno queens. I drive my car everyday. I want power now, and I don't want to wait and I don't lag. I'm convinced.

Once again vendors, here is a huge untapped market. I'm in!

EVOVII_SWE

iTrader: (1)

I think you got the pros and cons pretty much the same way I see them. I decided to order the 3071 kit from ATP and it will be very interesting to see how it works out. I have the Ti turbo in my RS2 so I will have a slower spool than now but I checked the UK EVO400 conversion to BB and full 400 spec (I never really got any answer on what that is) and it was about the same money as the ATP kit so I went with the later and hopefully I will be happy with it.

chuntington101

PLEASE let us know how the GT3071 kits is coz there is a bit of speculation about it in the UK and a lot of people are biding their time until they hear more about it.

Hope it’s as good as Norris Design keeps saying. And good luck.

Thanks Chris

EVOeight

Posted by Captain EVO: So like I said, its all about spool baby. Give me my stock turbo with the BB/Ti conversion. That is the ultimate. The rest are just dyno queens. I drive my car everyday. I want power now, and I don't want to wait and I don't lag. I'm convinced.

Once again vendors, here is a huge untapped market. I'm in!

That say's it all. Come on vendors, step up!

EVOVII_SWE

iTrader: (1)

Of course I will let everybody know, however I'm not sure how long it will take untill everyting is in the car, tuned and ready

evoate

iTrader: (1)

Yes, let us know about the GT3071R and please be honest. Don't say it's great just because you bought it, if it's not. We are all trying to learn and find out what works and what doesn't. I hope it works out to be as good as it sounds. I'm very much interested in this kit also, but want stock driveability. I also agree with Chris and Malibu that there's more waiting to be tapped from the stock turbo. We definitely need the BB conversion kit over here. I'd love to make 400 whp on the stock turbo (on 94 octane) without the lag and cost of a bigger turbo.

ShapeGSX

What makes you think that ball bearings would allow your turbo to efficiently spit out 27.5psi of boost?

ShapeGSX

I think you are going to be disappointed on all fronts. It might improve spoolup a tiny bit. Mass is mass, and you still have to accelerate it using exhaust gasses.

More efficient? Uhh, no.

More reliable? Again, no.

A Mitsubishi TD05H is just about as reliable as you are going to get when it comes to a turbocharger. Ripping apart the factory turbo to install a set of ball bearings is not going to make it more reliable.

chuntington101

ShapeGSX. A few points. A GOOD bb conversion will not rip the turbo apart anymore than servicing a turbo would. The conversion is popular in the UK and is done on more than just the EVO turbo as people are starting to use them on the Cosworth turbos (Garrett T28 through to T4’s). I have heard of very few problems.

If you read some of the previous posts then you would have seen that I have said that the turbo that EVO 400 sells (I think it’s a TME with bbs) will run at 2.4 bar. That’s more than what the stock TME can run at, therefore it is proof that it is more reliable. Also journal bearings generate more friction, and therefore more heat, than ball bearings (due to larger contact areas. Hotter oil I thinner and thus provides less lubrication. Less lubrication will lead to more friction (therefore more heat) and so the cycle continues until the bearings seizes up and there goes the turbo. So it is safe to say a good bb conversion will be more reliable than the stock turbo. Also if the stock steal components are replaced with Ti exhaust wheel and shaft (which are much stronger) then reliability is further increased.

On the point of 27.5psi (1.87bar??????) then as said before EVO 400 turbos have bin clocked running at 2.4bar so there is proof. And why wouldn’t it? I think you need to try and understand what a turbocharger is and what it is trying to do. Pressure is just a restriction of flow. The turbo is just trying to pump as much air as pos. you limit the amount of drive gasses to limit the boost to a level the ENGINE can handle, and at higher RPM to prevent the turbo over revving and coursing damage.

What the idle solution would be (and I think what WRC rally teams do) is run the turbo flat out. This will give you huge amounts of boost at low rpm. This stack of boost then translates into LOADS of torque bang in the midrange just where you need it! You then have to limit the rpm of the turbo by limiting the boost. this will provent turbo failure and exssesive heat build up in the charge air.

Please correct me if anything I have said is wrong.

Thanks Chris.

Zeus

iTrader: (66)

Josh,

Now don't go kicking everyone in the nuts... you know there is more to the upgrade that just that. I'd think you've spent some time on MLR on this subject. However, I think people are getting way too excited about the "spool" issue.

ShapeGSX

I run my Evo III turbo at 26psi. That is about 1.8bar. But I have a spike to about 30psi that tends to induce knock. I'm trying to lessen the spike. Are we talking a spike to 35psi, or steady state operation at 35psi to redline. There is a huge difference.

Are you talking 2.4bar (35psi) on a stock 16G6 compressor wheel with a TD05H exhaust wheel at high engine RPM? If so, I don't buy it at all. The compressor won't be efficient at all in that boost range. And the type of bearing used won't change that. Perhaps a quick 35psi spike at low engine RPM would be ok, but only a fool would be impressed by that.

I have trapped 118mph in my 3315lb car with a bone stock Evo III 16G at 26psi, flowing 44.1lb/min.

That isn't proof at all. It just means that you can overspin the turbo more easily. I've found that bone stock, sealed Mitsubishi turbos are very reliable for many miles, but rebuilds can be a gamble for sure.

Funny, I've always heard that the titanium exhaust wheel was weaker than the Inconnel version.

Ok, so lets talk about mass airflow. That is what really matters for torque and power production. I have gotten 44lb/min of airflow out of my Evo III 16G at 7156RPM. I have it datalogged. That is what it ran at 26psi. Earlier in 3rd gear, at 30psi, the system was only flowing 41.3lb/min at 5400RPM.

So what sort of flow can this Evo 400 turbo generate? If you get the same mass airflow (not CFM, CFM is useless) at a lower boost level as you do at a higher boost level, at the same engine RPM, there is no point in running the turbo that fast. It just means extra heat and wear. So we really need to see at what boost level this turbo dies out in terms of mass airflow.

No, that is absolutely right. But stating that 35psi is reasonable out of a 16G is silly without stating the airflow that it is pumping out at that boost level.

MalibuJack

iTrader: (5)

Its certainly nice to know there's a few others out there who have a similar perspective on this stuff..

I keep hearing about the "waste of money" aspect of the conversion.. I guess I'll just have to see for myself. I honestly think that there's really no wrong answer, just a bunch of compromises. I just can't see myself compromising the fun of driving the car every day just to make a number on a dyno.

What I just can't understand is the reluctance to accept that there are other ways to accomplish the same goal.

So far nobody has given me any compelling reasons why its better to upgrade to a bigger turbo besides "More horsepower" or the magic 10 second quarter mile.. nobody seems to talk much about drivability, servicability, durability, etc..

I don't know about most of you, but my biggest concern is being out on the road and having something fail.. obviously we can't fix everything, but its comforting to know that in the end I'll still be able to roll into a dealership if I'm on the road and there's a good chance that I'd be able to get something that will get my car up and running again.

Obviously this conversion (or even just a stock Ti turbo swap) isn't for everyone.. But I wonder in the end how many of us actually use the car to its abilities STOCK let alone modified..

MalibuJack

iTrader: (5)

This is certainly an interesting debate at the least..