Sydneykid

Good question R31 POWER, but if your engine has enough blow by to cause idling problems, then it is not the blow by that you should be worried about. :spew:

Let's try this one, it's the open to atmosphere catch can; The idea is to only have one connection from the cam covers as they are joined by the standard pipe. The PCV valve and the connection to the inlet before the turbo are blocked off. You can have a return (drain) to the sump form the catch can if you like. Don't T it into the turbo oil return as it is under a bit of pressure and the oil can run up into the catch can. The other 2 options follow in separate posts.

Sorry guys dead lap top, I'm working on it. :thumbdwn:

As Roy posted and he is absolutely correct. We found that we get more power EVERYWHERE, on boost, off boost, even at idle it has more power. But we never just stick a turbo on, there are lots of other things that make a dfifference, refer previous list.

Your wish is my command :slap: Your example is somewhat valid exept there are 2 problems; Mechanic #1 should have told the owner why he undertuned (your word), I prefer "left a margin for safety". Mechanic #2 deserves the suing (and bad rep) that he is going to get. :wassup: If you hang around here and read enough you will find a lot of information that, as a car owner, will help stop this happening to you. A dyno read out with A/F ratios, ignition timing, boost and a few others will help you (and other willing helpers) diagnose exactly what is going on. You will know what mechanic #1 has done and it will also help you stop mechanic #2 from doing something stupid. As I said, much to learn around here, worth the time though as it is priceless.

With this information........ you expect me to be able to tell if the turbo is good for 225 rwkw? :wassup: Sorry I can't do that, there are at least 20 different combinations of T3 and T4 turbines & covers and compressors & covers. I have no idea which set the turbo builder has used. Since they have gone to the trouble (and expense) of doing a ball bearing hi flow then chances are it is a worthwhile upgrade. My best suggestion would be to find out who did the work and ask them, they should have a record via the turbo serial number.

Firstly you need to remember that boost is simply a measure of restriction to airflow. It is airlfow itself that makes power, boost is really irrelevant. If you remove the restrictions in your engine, then you can make more power at lower boost. :idea: Moving on to your question, 300 rwhp is ~225 rwkw and that is pretty much the limit of the standard injectors. RB25DET internals seem to handle ~300 rwkw (400rwhp) as long as the tuning is spot on. There are a number of threads on this subject, you really should do a search.

Ahhhhh no! :dump: "the larger the turbo the greater the boost the larger the gain" that's not correct, if I choose the right turbo I can actually have more power at lower boost levels. Boost is a measure of restriction, airflow is what makes power. :idea: If I do a leak down test, check out the internals with a bore scope, drain the oil and have it annalised, I can tell what condition your engine is in, pretty much spot on. If I use a Dyno Dynamics dyno running in Shoot Out Mode, it is very difficult for me to a get false result, one that is impossible to pick anyway. :angel: This is much more reliable than taking it to "the track" where driver skill, suspension set up, tyres, ambient conditions etc etc make much more of a difference than a tricked dyno. :headspin: And if you get "boom blown piston" then put that down to poor tuning and diagnostics, it's got absolutely nothing to do with "hammer". Exceeding the limit of the metalurgy will also do it just as effectively. :innocent: There is much to learn, that's why I come here. :aroused:

You got it.

Honestly MIC33R, I have no idea what the specs are, it is an off the shelf GCG RB25DET ball bearing hi flow. If I had to guess it feels like no bigger than a 0.64 A/R Turbine Housing with around a 76 trim turbine in it. The Compressor Housing looked to around 0.70 A/R with maybe a 48 trim compressor. But all that is really guess work, I have deliberately never measured one.

Ooops, that's the air inlet to the turbos, not the outlet from the turbos to the intercooler. :wassup:

Hi BOOSTD, it still has the standard exhaust manifold. On one of our other engines we use a GTSR exhaust manifold (low/rear mount turbo) and it holds good power to ~8,000 rpm. So I think that could be it. I can get a little more top end out of it by retarding the exhaust camshaft timing, but the average power is lower. So I removed the adj pulley. Maybe a set of 264's would boost the top end, but then I would loose the VVT. Honestly, it is so nice to drive, I really don't want to change anything. The 11.9 was on Mickey Thompson ET's, I have tried Nittos and it was only a couple of tenths slower. I might give the new Goodyear Radials a go next time, the guys are getting goods results from them. :aroused:

I would have removed the T4 internals from the VL turbo and stuck them in the RB25 turbo. All you would have had to do was machine the RB25 turbine cover. Coupla hundred bucks with new seals and gaskets. Maybe worthwhile thinking about.

What engine is this?

Well done WazR32GTSt, I was starting to doubt myself :confused: No I wasn't, I knew if I could get it to work anyone could. :thankyou:

Several, what do you want to know?

OK I just have to jump in here, I have seen the engine dyno sheets for an RB26 equiped with a pair of Group A turbos that made 471 kw at 1.9 bar. That's with a standard R32 V SPec intercooler as well. The car it went into was red, some bloke called Richards drove it. Oh btw it had 9.3 to 1 compression ratio as well. Just 'cause SOME people can't do it, doesn't mean EVERYONE can't do it. :thankyou: PS Everyone knows Perth Kw's are bigger! :confused:

There is far more to a 0-100 time than the turbo, vehicle weight being the most obvious, followed closely by engine capacity. So comparing a VLT with an R33 GTST really is a waste of time. :headbang: To answer your question, I have an RB20DET with an RB25DET turbo on it and I wouldn't even think of taking it off and puting a VL turbo on. The average power would suffer greatly, plus I would have to change a whole pile of stuff to get it to fit. The big advantage of the RB25 turbo on the RB20 is it fits straight on. Just swap over the wastegate actuators (the RB20 one has a higher spring rate).

Mine doesn't "suffer" as much racing, as it does in ciyt traffic driving to work:wassup:

Shoot where would you like me to start? Shaft diameter Bearing width Seal pressure Wastegate in dump Wastegate diameter Oil spray enough?:headspin: Don't get me wrong, for a 1986 turbo they were fantastic. But that was nearly 20 years ago and turbo technology (particularly aerodynamics) has moved on, a lot.

Hi Benm, I generally use a spread of rpm that corresponds to the maximum rpm drop of upchanges (1st to 2nd is usually the worst). So that would be 4,000 rpm to 7,000 rpm in this case. I posted the numbers a while ago in another thread, I don't have the dyno sheet with me but, I think this is them.............. 7,000 -------- 246 6,500 -------- 266 6,000 -------- 261 5,500 -------- 252 5,000 -------- 231 4,500 -------- 202 4,000 -------- 149 Average -------- 229 Did that answer your question OK?

When I read the post heading I thought WHY WOULD ANYONE BOTHER? :looney: But then 7 posts later, all was revealed :idea: So I gotta ask, why didn't you put the T4 internals in the R25 turbo?

What RPM range?

And they have balls! :aroused:

How long (not how often) can you run NOS before the engine suffers?