Dale FZ1

Can anyone help with the right part numbers for Whiteline front springs to suit the old Sydneykid spec Bilsteins? I have the rears which are marked 23139, noting that there is a slightly different number on the Whiteline catalogue. What I want is the fronts, just doing the homework on part numbers before trying to source a pair. Secondly, it appears that the desired ride height is ~345-350mm from wheel centre to top of wheel arch. Does anyone running this spec suspension know what groove the spring perches are located on to achieve this ride height?

This is probably the most pertinent question - are they spec'd for long service, or likely to be a smokey squealing mess within 20000km? I'd suggest that Kando the Great has learned many lessons from Grand Master Mitsu and doing a fair effort at imitating, not buying in their product. If the quality of metallurgy, specification and tolerances are equal to Mitsu then these things should be difficult to overlook. Mind you, there are also some reasonably priced BW units in the Airwerks range too - with an established quality control base behind them.

48T GT3037 would be an odd-ball but still interested to see if anyone had ever seen or used one. I suspect it would/could have been spec'd for those twin GT3037 setups for RB26 that were floating around a few years back

I'll share a little recent/ongoing boost control experience with GT3037 Pro S on 30DET. Started with 12psi actuator running straight feed to the actuator, no BC. Definite problem with boost slowly building then running away to 19psi and tapering to 16psi; not readily fixed or changed with preload. Changed to a 18psi actuator, trialed with straight feed again. Slower boost build to peak 19psi, again tapering to 16psi. Obvious that actuator spring strength affected the rate of build, and was generally more effective. Activated and tuned the Vipec BC map. Found that it is very sensitive to adjustments, and duty cycles were effectively addressing the characteristics observed when not running any BC. ie. high DC to promote fast boost rise, quickly tapering to allow the actuator to do its thing and limit boost to the observed peak. Then finally start to ramp DC back up so that boost didn't fall again beyond 6000rpm. And come to the conclusion that the turbine is probably getting to its flow capacity and starting to struggle a bit. I did find that the boost "curve" was a bit wavy and didn't look super smooth with up to 1.25psi variation through the range. Not my ideal but it works ok. Comment to OP: make sure you use an actuator not far removed from your target boost. Light-pressure actuator probably won't cut it if you want to run some bigger boost levels. Get the preload set right. An extra turn or two on the rod will make a difference. Be prepared to play with EBC settings to get it "right" or at least to an acceptable degree of control. Good luck and don't worry too much about the power number. Look at the shape of your torque curve.

If he was prepared/able to run E85 exclusively, then agreed, 10:1 might be do-able. But I wouldn't go there with 98 pump petrol and expect to exceed his current output with the SR20 AND expect the engine to live. The oil jets are intended to take out the thermal loading and expansion of the stock cast pistons. The extra cooling effect of alcohol fuel might negate the need for that. One thing is for sure, high static CR and decently high boost levels can quickly lead to detonation unless fuel and ignition is right.

Emphatically, YES. Regardless of whether you're paying for someone else's time, or using your own time, dropping in new valve springs while cams are out is a no-brainer. Just got to be sure the method used will ensure the valves don't drop down into the chamber. I hate having to go back over my own work to make an improvement I could/should have made the first time around.

What is the format on the pan? ie. just round circles, or do you intend to lay out some motorkhana style tests?

Stock RB25 top hose fits fine.

Trent did you try variations on total increase in overlap? Eg IN+4, EX-4? Still gives you 8 degrees but I'm interested to know how it affects the torque curve. Using a Tighe grind on my 30/25 and it seems that there is a point where the mid range is noticeably fatter but torque at the top end falls away and you end up short shifting a bit. Note this is a bit of subjective feel, trying a few settings on the road before slipping it onto the dyno.

There was only a handful of people around that ever went with the GT3071, and no real evidence of ANY response superiority over the GT3076 despite its inability to flow as much air as big brother. I see it as a hard one to call whether there's going to be this great real-world improvement or not - but at least it gives the punter more options to trial. Look at the flow comparisons between GTX3071 and GT3076 - compressor can do much the same thing but higher speeds required for the 71. Both would in honesty require the 0.82 turbine housing, so hot side flow capacity/efficiency is identical. Sure is going to be interesting to see a few fitted up and running to see what eventuates.

It's going to be interesting to see how these things match up to "typical" installs using the old-spec GT series turbos. With the increased compressor flow comes the need for increased turbine flow and maybe a touch less low end response. I'm left thinking the bigger 1.06 housings will become more of a common selection depending on engine and turbo combination. Just taking time to digest it all.

It helps to know what characteristics you want before you start. Some combinations are deceptively fast ie. cover ground quickly and don't feel it. Despite the power number, it might deliver the goods if you can directly compare with something else. I'd be interested to see a dyno sheet, even if it only tells part of the story... Well you've already asked someone who is a specialist in the field. I wouldn't think that a housing upgrade would cost the earth, and if it stops the thing choking up high then trialling it would be worthwhile. You may also find that any loss of response is academic when you look at the entire picture. You might be surprised what a bigger turbine housing will do, and the extra ignition timing that it allows you to run. If you went with a -32 spec 2871 all you would get is a smaller turbine rotor with the same sized compressor FWIW, I found a -31 spec (ie 48 trim) GT2871 high flow very good, progressive and fast with 225rwkW. Never looked fast but it really covered ground nicely for a road car.

So what is it making - somewhere around 230-235? Looks like you've got a milled (high flowed) OEM turbine housing. If so I think you'll find they're somewhat smaller than 0.63, but there is no marking on them to indicate. Might not be a good match with the rotor, can lead to a bit of choking and below expected outputs. You might do well to consult with a turbo manufacturer/remanufacturer about housings - perhaps Hypergear can help out if that is the culprit.

For some reason when I log into turbobygarrett.com I can't see the GTX series in their catalogue. And the pics hosted on this thread won't open either??? But if Honeywell have stepped up a size on the inducer then it's no wonder they have shifted their maps over to the right and claim they will support higher outputs than the previous GT models. Was there an update to the turbine specs that they are using, or just the compressor?

So what did you trial? Just the bearing type vs plain bearing, or did you also swap comp housings and trial ported shroud vs full shroud? Assuming no changes to the tune were made. The overlay shows little quantifiable difference but is there any difference on the road and if so which gave you the best "feel"?

Just trying to understand. So the anti surge brings the boost rise and torque on faster, but not making as much maximum at higher rpm? I guess noise is the inevitable by-product of giving the air an escape path, but wonder if the number of slots/holes, and position along the blades makes a difference?

Adrian I'd say you'll spend less time and effort by just getting the front pipe made, and the car will be on the road. Let's see this thing running please.

In building my RB30, I checked out extrude honing and spoke to one company that provides this sort of service. Found out that they commenced the job with a fair bit of die grinder work and then pump the abrasive medium through the gas passages to finish off. I looked at the stock manifold and then took to it with my porting tools and abrasives. The biggest two areas needing attention were the sharp shoulders inside each primary runner, and then a pretty ugly looking collector area. Spent probably a few hours from start to finish, lots of looking and planning, with pretty satisfactory looking results and much reduced turbulance inducing edges + a fair go at port matching to the head. I followed the same principle in doing a basic porting job on the head. Bugger all material removed, but a decent amount of time spent smoothing sharp edges and blending curves. I'll have no idea if it improved things because no direct before/after tests were possible and I didn't put it on a flow bench. But I know my approach wasn't that far from the job being enquired about, and the job didn't look or feel much different from a few heads I've seen done by reputable porting services. I'd agree with Wolverine about the manifold unless you have the time, inclination and gear to do it yourself. And even at $500 you're a good way towards paying for a 6boost or ETM.

If that's the approach he has, suggest you consult with and pay someone different.

It's been covered before, but I found this to be a most useful resource, includes pics. http://twinturbo.net/net/viewmsg.aspx?foru...&dtSearch=0

It is a fair bit of compressor for the engine. Are you averse to having the housing milled? I'd tend to agree with Matt; playing with cam timing will realise changes in the gas trapping dynamics and the rpm where things come together. Seems that addressing it by at least trying to dial the cams would help. Alternatively if you have good boost control, why not drop 2-3psi in that range? Depending on your rpm ceiling you might then pick up more mid range efficiency by dialing cams to suit that arrangement. Win-win if you could achieve that.

You seem to have answered your own question. From a technical perspective, a manifold that allows more efficient flow and cylinder scavenging is the thing to have. Also an external gate properly set up will offer better venting and boost control. There was a comment from Al who wants to go to virtually the type of turbo system you ask about, from an IW, collector style manifold on the basis of boost control and efficiency. That would/could open up the option of using split pulse too. But there are many people easily achieving 400 rwhp +/- 15 using OEM manifold and IW turbine. A very tidy result at significantly less outlay. And it works superbly on a street car. If you were keen and capable, it is possible to smooth some internal sharp edges/restrictions in the OEM manifold too. Unknown exactly how much advantage this gives, but every little bit would help. If you were chasing higher hp and using a GT35 turbo, then I'd have no hesitation in going 6boost + EW. For me it's a question of performance target and budget.

I don't think you're likely to kill the engine by using the smaller restrictors, but noisy lifters at idle would be a PITA over the long run.

Moogley you've seen the man's advice. It's a fairly common experience - the issue is obtaining sufficient flow from the pump at low revs (idle) through a small orifice to fill the hydraulic lifters. I have a stock pump with 2mm shim, and 2x 1.6mm feeds and no VCT. Hot or cold start it takes ~ 2-3 secs to pump up the lifters and otherwise the top end is silent at any engine speed. I expect it and can live with it The other thing I found was a big impact by the grade of oil used on cold start oil pressure and lifter noise. The guide is just that, not a Bible. If you're 100% road use then stick with the stock feeds to avoid noisy lifters. But do drill out the internal oil returns in the block and head.