Dale FZ1

That's brilliant. I suspected it would liven things up a fair amount response wise. Let us know how it goes with the top end power. Hopefully the power won't "nose over" and die in the last 1000rpm. What is full boost at this point? How does it feel to drive? Progressive or coming on with a rush?

Bring on next weekend. Man I hope that turbo gets "woken up" by the housing change. It couldn't hurt to try one heat range cooler than stock plugs, but the benefits are likely to be marginal for normal road use. Maybe worth slipping a set in if planning extensive dyno work or extended high speed/high load running.

Motion seconded. Use a little care with your spanners and I'd be surprised if there was a problem with stripping/dripping. cheers

Has it surged from the time you fitted it, or commenced doing something unusual only recently? Surge basically happens because the compressor is attempting to pump more air than the engine can ingest - the literature describes how a series of pressure reversions occur between the throttle and impeller. Generally it should be at less than full throttle, and under some load (boost) as you describe. DO check your BOV. cheers

No it is definitely off-boost. The noise really is like "CHOO" and can be felt from the driver's seat. any other ideas?

Two factors have a major impact on the rate of acceleration of an impeller: radius mass Increase either of them, and the ability to build boost quickly is diminished. Note that Blade numbers, shape, inducer size also impact on compressor performance. cheers Dale

I sent PM yesterday. No reply, no pics? Can you give more detail on the high flow? Origins/exact specs please. cheers Dale

The closer to the source, the better. If you've gone to the expense of picking up two pyrometer kits (and they're not cheap), get the bosses welded on to your dumps. You can always use a bung if/when you've had enough of monitoring exhaust temps. Monitoring temps pre and post-turbine would be an interesting experiment, similar to measuring back-pressure and probably a useful indicator of turbine efficiency. I just don't know anyone who's done it. I have one installed in the dump, parallel to the O2 sensor. My RB25 typically runs 550-620 in open loop light load running, 630-660 in close loop cruise, and about 720 max with a good hard full power run (not just a quick blat through the gears).

I'm trying to trace an odd noise happening with my RB25, noticed it over the past month occasionally. Basically accelerating only moderate, either off-boost or 1-2psi max and an odd noise comes from the engine. Initially I put it down to the air-con cutting in, and the belt needing more tension. Checked that, same noise happens periodically. The noise seems a bit like a sneeze and is only really audible when the windows are down. I suspected it may be a backfire (funny - it's not a violent noise or anything) but it is happening only when the car is under load, and nearly always happens accelerating away from the same intersection, heading uphill. Any ideas where to look? cheers Dale

Pick up the phone, dial the freecall number to Mobil and speak to a techo. You should find that a full synthetic is designed and rated to easily withstand 105 deg C temps. If that's the max you get, little to worry about especially for a road car getting limited thermal loading. If you want to run track work, oil coolers are an easy way to achieve more consistent temps and reliability.

PM me. Let me know where you are. Have a stock system from cat-back. Cheers

I'm on the lookout for a set of Z32 16" wheels, don't want anything that's all gutter rashed. Interested in either turbo/non-turbo variety. Located on the Sunshine Coast, Qld. cheers

Showing my ignorance of Garrett product, but can you share whether there is a suitable 76mm wheel in smaller trim size with fewer than 7 blades? If so, is it an expensive proposition to swap in a different impeller? Still mulling over those flow maps you provided too - great stuff!! The initial feeling is that the flow capabilities of the compressor and engine are mismatched, and I'm having a look at that aspect, with the assistance of the tutorials at turbobygarrett.com, and the maps provided by Discopotato03 Big power from a moderate-small capacity road engine while retaining low-lag (note : not lag-free) response is not going to be easy. 320 odd kW (crank) from 2.5 litres is big power, and that concept of average power through the range comes back into focus when looking at response and useable power. Otherwise all those engineers would have got all their turbo matches spot-on. It's clear to me that virtually all engineering requires a degree of compromise. Paul, we don't know for sure whether fuel is a major issue or not. I believe Mafia has to try a simple test to eliminate that from the equation. In the absence of pump 98 octane, it might be worthwhile getting a quantity of aviation fuel and do a dyno run. That will give him some answers about the top-end pinging initially complained about. The GT-RS would have to be a pretty good unit but there's not a lot of comment out there by people who are running them. Likewise the 2835 Pro-S, though I've heard they tend to come on with a rush (that coming from a member who is running a 2530, against his brother's 2835). As with most things it's a case of knowing what characteristics are most desired ie. the compromises to accept or reject. I'll post a bit more later on. cheers

It's got to be the way to win more customers.

Considering that the T04 range was conceived/developed to be tailored to many different applications including diesels, I'd be interested to see a flow map for the 52 trim S with 0.7 A/R housing. How about it? I haven't found one (and have tried) but welcome someone to post either a link or pic. I think BHDave may be right but would be good to confirm. His comments about requiring more boost to make less power are good evidence of flow/pressure ratios/efficiency. Also as a matter of pure cost containment, if Mafia can get his mate to machine up a std RB25 housing, it's probably worth a go. I wouldn't like to see good money going after bad, but it'd be good to see him hit a happy medium. cheers

Separate but related info from above. The unavailability of a suitable internally gated housing for the GT30 core (in Australia at least) seems about to be corrected. Here is the information from Garrett Aust. "we are producing .63A/R and .82A/R Turbine Housings for the GT30 (Turbine Exducer Diameter 54.86mm) range of Turbochargers, manufacture of the tooling required is in progress. We would hope to have the finished Housings available about end March 2006 At this stage we don't plan to make anything smaller All Mounting and Outlet Flanges will be same as GT35 currently used on BA Falcon XR6 Turbo" Racespec has made it known that he will be able to supply these complete units by around Easter. No doubt this is the case with GCG, HP in a box, MTQ etc. Discopotato may be able to chime in here re the compatibility of flange patterns because I don't have much knowledge about the specs used by Ford. Hopefully all of the above gives some hope of correcting the sagas Mafia is having. He has gone to a lot of work and deserves credit and assistance so he doesn't blow a heap of $$ (end of grand-stand). cheers

Ok Mafia has given me the numbers he's seen on the ID tag fitted to the core of this turbo unit. He's read it as 700177-5011 Looking at available literature, I suspect it will actually be 700177-0011 check this site which gives specs: http://www.turbomaster.info/eng/applications/bearings.php For that CHRA number, it should therefore have Compressor 76mm T04S, 55mm inducer, 52 trim Turbine 57mm GT28, 54mm exducer, 90 trim As previously noted, he has a 0.7A/R comp cover. Not sure of the specs on the cover (read: nozzle/tail sizes), but it clearly has a bloody big bell-mouth. Hot side is the VG30 housing for which there have been a number of "guesstimates" on the A/R. Fact: nobody's (on this board that I'm aware of)actually sectioned either a VG30 housing or one from a RB20, 25, 25 Neo, so the A/R of each is not known. It does seem fair to say that the VG30 IS larger, but by how much we don't kow. What would be worth knowing is whether anybody has easy access to a VG30 or 25 Neo unit so that they can accurately measure (using verniers) the size of the turbine impeller at the inducer and exducer. A reasonable computation of the wheel size can be made (max diameter + trim) so we can at least see what was matched by the engineers to that housing. Until that is known I would not like to draw any conclusions or make assumptions about flow restrictions with Mafia's combination (even if they may be correct). cheers

A bit like a PC - you have to configure it so that it knows what its working with. The autodetect and multitude of drivers that most systems come with these days makes it far easier, but the principle is the same.

Man, this is a sad story about a mod that should have been THE duck's guts with the effort you've gone to. discopotato03 given that these guys have both done a hybrid using VG30 housings and both ended up with what appears to be a choke in the turbine area due to the flow capacity of their compressors, can you see what similarity they have in the CHRA?

Thanks jmac. It's good to see you're satisfied with the result to this point. There are many instances where the modifications lead you to having to keep the revs up or down just to avoid lag and/or the massive rush as it all comes on too strong. My view is that besides being strong, it still has to be streetable (tractable) and not threaten to light the bags/snap sideways any time you squeeze the throttle coming off a roundabout or turning a street corner. Probably showing my age, and preference for OEM style power delivery, but I have strong recollections (as a spectator) of the Group A Ford Sierra Cosworth RS being "challenging" to drive around windy tracks. That of course was one reason the GTR became so dominant with the level of traction available. Bass what is your level of satisfaction with your setup and power level? cheers

Ok, reading between the lines it does come on like an animal and then predictable and obviously fast? I do have to agree there is plenty of meat, very early in the curve. Please give us an idea of what it's like in on/off throttle driving. Bass how similar to your turbo is this unit (apologies if there's comment on this earlier in the thread)? cheers Dale

Looking very nice... I see that boost spike as it comes on - maybe not ideal? Did that cause any tuning problems? Also interesting to see how you have a very wide plateau of max power; what does the shape of the torque curve look like? and how does it feel in the higher revs beyond that 3500rpm point? Also is there any feeling of lacking response or engine flexibility right down low (eg. trickling along in 3rd or 4th @ 1800rpm and squeeze the throttle) compared to stock? You should be happy overall at this point though. cheers

I'm tending to agree here... The other frustration I have is that my laptop's battery has died - only works on mains power until the warranty claim is sorted. So I still haven't been able to verify the workings of the interface.

Remember to look at the shape of the curve Jono, not just the highest number. yeah, I agree it's impressive but watch for dips through the range.

High revs are also the reason why bikes went to 6 speed gearboxes while cars were still running with 4 and 5. You're going to want DEEP pockets, and have some pretty special driving capabilities. If you're serious about motorsports, have a really good look at what other people are doing first.