Dale FZ1

Dunno about big and bad. But Mick's suggestion of a 7670 1.05 sounds about right to me.

Either way, this thing needs flares!!

Valve size is one part of the puzzle. Efficient flow paths to/from the gates are right up there too. So if you could run similar manifold/piping as cited above ^^ should be ok.

Big flowing compressor needs to be matched with a turbine capable of flow. Otherwise the engine effectively has a cork up its arse and can't breathe out. So it won't get near 400kW, and streetable response isn't there. Better achieved by using a different setup. https://www.sau.com.au/forums/topic/426059-forced-performance-hta-turbos/?page=47

You'd want the CEA (ball bearing) version, and if you've got the budget to build a 400+kW Skyline then you won't shy at the cost of going with a split pulse/twin gate setup that's well designed (ie not a dodgy cheap China manifold and piping). A 0.6x turbine housing would completely defeat the purpose of this size turbo, just choke the thing and frustrate you. I'd expect a decent setup on Neo 25 to perform best across 4500-8000rpm An excellent alternative complete HTA3076 setup complete bolt-on capable of nearly 400kW is currently up for sale by 34GeeTeeTee. Well worth a look.

Understood. By way of a recent experience that may help: We've shaken down the Emo after a prolonged upgrade/build period. I appreciate that a 4G63 - SR20 comparison is not apples-apples, but it is a 4wd platform that counts for heaps. No porting, but lightweight retainers, upgraded springs, and (against my advice) some Jap cams advertised specs around 270. Actual cam doctor measurements showed significant variance from advertised, and staggered/unequal between inlet - exhaust. Turbo choice budget Kinugawa TDO6SL2-20G split pulse 10.5cm. Result on 24psi bleeding to 22psi by 7000rpm was 380awhp, monster mid range torque from 4000rpm. Idles good and smooth at 900rpm. Doughy sub 3000rpm. We have assessed that OEM cams would probably have brought the useable torque floor down 500rpm, and manipulating boost control probably seen no loss at higher rpm. Car was second quickest in its category (behind a modified R35 GTR) even though we were just shaking it down. So it had "enough", and we aren't focused on hp numbers either, just a quick/reliable track car. SR with big duration cams really requires revs, and those things have a deserved reputation for spitting lash pads when using the revs. Talk to the people doing your work, but I agree with komdotcom, OEM cams will only make the cam train work with much less stress for probably as good a result.

Tuners and engine builders are not always operating on the same plane. Or even a high plane. And it's no good if they don't understand what you're trying to achieve when recommending specs. So lots of opportunity to miss the mark. Making an engine run lean where you're trying to make it "come on" is counter productive IMO. And ignition timing is very important, so if you can, you should look at the ignition map and learn. There's a lot of easy to access net resources, try hp tuners for a look. Suggest a change to 0.6 turbine housing will help with the mid range boost response, at the expense of some top end revs If you're running a 4wd Bluebird or Pulsar (guessing from earlier post?) you probably want (ie definitely need) bulk mid range anyway.

Not thinking about rwd vs awd or the actual power number. Turbo "should" perform ok. What turbine A/R did you go with? Also whatever your tuner has done with ignition timing low-mid range has a massive influence.

Bit of a loaded question without disclosing turbo size/spec and static CR, and even fuel type + ignition mapping "down low". All those things will play a part. Without committing too much $$ you could try a dyno session and adjust the current cam phasing to see if it will build better torque at lower rpm. Otherwise on topic, there's plenty of SR (and RB) owners running more basic engine upgrades with just a turbo change and OEM cams who are very happy and don't need to rev the tits off them to get satisfactory performance. Turbo spec will have a massive impact on how the engine performs over its whole rpm range.

The first and most obvious difference is complexity and cost. Packaging/engineering difficulties being part of that situation. The second and less easy to quantify with a dyno sheet is throttle feel and how it drives into boost or how it behaves on gear changes etc (different from how it runs at WOT). Otherwise, the power figure will (should) be higher with a bigger housing simply because the engine can exhale more efficiently, lower backpressure, better scavenging, less retained heat etc etc. There are reasons to go with either approach, and quite a few traps that can prevent "best" outcome for each. I'm currently engineering a 6266 0.8 single scroll 6boost setup onto a basic 30DET engine. Knowing that engine performance is only a part of what makes the car go fast.

Turbine housing will be the deciding factor on your power figure, and response. Eg. single scroll 0.84 will be way different from split pulse 1.15. If you're limiting yourself to 2 bar, could range from 450 - 550kW. Your rpm ceiling will also play a part in that figure. So there's a few variables.

^^ I'd like to see how the log looks if you'd done the WOT run from 2000rpm. 3rd gear and 4th gear.

100% the right sort of diff these things need. Put a few km on it and report back with impressions. Just don't run any friction modifiers in the diff oil. LSX90 is all that's required for maximum effect.

I haven't examined either of those units in any detail. Not so sure that the flow (rated power) figures are for a single unit there though... But it's an example that isn't in keeping with the original question. eg. different housing, different trim size. And without a detailed inspection, it's quite possible that the blade form (shape) is different. The case I cited was for a TDO6H-25G. Turbine rotor was available in either 11 blade or 12 blade when I purchased. There was also a 9 blade with the same critical dimensions but completely different design. Compressor impeller options had 3 choices, but they were all different designs (and prices). Two different compressor housings, and up to 5 different turbine housings were available. It would be very easy to get into a muddle with so many choices, which is probably why the engineers do the development work and the marketers generally offer only basic spec variations eg. turbine housing A/R.

It's much the same as for any pump, or even boat propellors. Without changing ANYTHING other than the number of blades, it will pump more air earlier (compressor), or apply more drive to the driven shaft (turbine). And then become less efficient at higher pressure ratios and mass flow levels. More blade surface area to do the work helps shift air at lower rotating speeds, and the same factor eventually becomes a restriction. The use of extended tip blades, light weight impellers, half-height blades etc are engineering solutions to either flow/response requirements from a given size package, or noise reduction. It is still possible to option some turbos with different blade counts, with a realistic expectation it will perform differently. By how much is the unknown factor. Kinugawa is one that I know of.

^^ Tyres are bolt-on speed, without question. The rubber I'd suggested is all a step up on what Dan currently runs, but slicks are a natural end point. Depends on category rules - I think his class required treaded rubber? Bars are a topic of debate/contention. "Best" bar spec is relative to springs/shocks spec and they have to work together. There's more than one way to get a desired result. By way of example, my 33 currently runs a stock front bar. The rear bar is removed. Car isn't perfect, but it's got a workable/useable balance to the handling and last season it was one of the quicker things in its category.

The "hard points" of the car haven't really changed from before/after. ie. same weight, same max power, same rubber, same shocks/springs. And the driver may have been a bit rusty? Achieving a large number of laps at or near your previous best pace means the day wasn't a waste, and you'd have to take a positive from that. Where your best pace sits relative to others is a different issue Pic on the second tyre doesn't look great (LH front?) with that lateral cut/split across the face. Make sure it's not heading towards a failure. If you do get something new, try the RSRR, or a set of NT01 or AR1. If 9" rims and 255 rubber would fit without clearance issues, go with them all round. Get into the habit of monitoring and managing pressures. If MCA are giving advice about what an S13 needs re: springs/shocks/bars, it comes from plenty of experience. You don't have to use their gear, but I would make the change without hesitating. But be certain that you are speccing the car for a purpose. If you require any on-road ride quality it's probably going to need the lighter spring rates. More important IMO, is balance front to rear. Get a plate style LSD (eg Kaaz, Cusco) to replace the helical S15. Aim to get your ride heights in a happy area. MCA can give guidance about this point. It is fairly (ie. really) important, sets the suspension arm angles, not referring to the way the body looks or how much room there is between guard and tyre. All of the above is about making the whole car "less wrong" and more mechanically suited for the job. Now - chase your alignment settings. What you used should be a reasonable starting point. When you're at the track, be prepared to alter ride heights to address under/oversteer. Don't just make small changes to the shocks and expect to feel something hugely different. I generally try mid range shock settings both ends, then one end go full hard, full soft to feel the difference. And repeat for the other end. You will quickly find useable shock settings from that.

"Splash guard" under the engine is an essential part of managing cooling airflow through the radiator. Ambient 25-28 isn't hot...

Best course of action is to identify if you're getting silly pressure fluctuations. Install a decent pressure sensor in the fuel line, and log. The FPR800 may not be the poor performer.

Full credit where it's due. This thing looks great, and the effort to package all those bits and pieces is immense. Pics show a lot of detail work you've undertaken. The Modena box is the part that's most impressive!!

If bigger sway bars upset the balance, revert to stock and see how it feels. (knowing there's a wide variety of opinion regarding bars) Your alignment settings are reasonably benign. If the front outside edges are getting caned, chase another -1 degree of camber. Might put it in a happier place. More caster = good. Consider whether how you turn-in, lines held, and throttle application are contributing to understeer and tyre wear. Some pics of the car cornering, or honest input from an experienced "proper" driver who's got time to watch you could help. RSR-RR or Nankang AR-1 would be worth a look when you're prepared/able to spend on new rubber. Proper R spec tyres will always be the fastest option, but it sounds like setting up for doing more track km is the smartest move.

Great to see it ready (almost). What sort of alignment settings are you chasing? Tyres?

So what did you end up doing George?

Very nice indeed! Bar work, front tubs, column mount, pedal box. And a proper gearbox. And more. Keep the pictures coming. Don't make it too pretty - you won't want to use it.

Lithium's comments ^^ are where it's at if there's a burning desire to go split pulse on RB20. Use its advantages (ability to rev and maintain VE). The 7163 will allow it to exhale more easily, so of course it will make the numbers up top if torque doesn't drop away as fast. For "minimal" response compromise down low compared to the 6758. Personally I would give a much closer look toward the TD05H-16G (or 18G that Roy has surplus to needs), run a half respectable high mount manifold (eg 6boost) and EWG. Simple, robust, cost effective. And the manifold + gate will easily transfer over to a 25 or 30DET if you decide you want cubic inches.