Fastrotor

Hi Guys, this one is for the mechanical engineers and techos out there. I'd been struggling for a while to figure out in my head whether gas flow in a pipe would drop more pressure when hotter than cooler. It seems hard to find formulas to work out pressure drop that include temperature in the calcs on the net..... but i found one site that i took the time to work out all the values to get a resonable result. http://www.efunda.com/formulae/fluids/calc...iction.cfm#calc here are my entered values : Inputs Pressure at A (absolute): 39 (psi) Average fluid velocity in pipe, V: 110 (m/s) Pipe diameter, D: 6.35 (cm) (2.5") Pipe relative roughness, e/D: 0.000708661 (M/M) (stainless steel) Pipe length from A to B, L: 6m (4m actual plus 2m for bends effective length, a guess) Elevation gain from A to B, Dz: 0 Fluid density, r: .815 (160deg c) Fluid viscosity (dynamic), m: 0.02464397 (cP) Answers Reynolds Number, R: 2.31 × 105 Friction Factor, f: 0.0196 Pressure at B: 37.7 psi Pressure Drop: 1.33 psi Volume Flowrate: 348 l/s Mass Flowrate: 0.284 kg/s When i change the temp of the air to 100 deg, (ie change Fluid density and Visosity numbers to .946 and 0.02210196) then i get the following result Answers Reynolds Number, R: 2.99 × 105 Friction Factor, f: 0.0193 Pressure at B: 37.5 psi Pressure Drop: 1.51 psi Volume Flowrate: 348 l/s Mass Flowrate: 0.330 kg/s NOW..... an explanation what this post is about..... i have an intercooler in an R33, using std piping route, then on to front mount.... so therefore one side is alot longer than the other side piping. My hot (compressor) side is the long side, going to drivers side endtank... cold side comes off P/S to plenum. I wanted to prove mathematically what would be the best side to have each on... (ie hot = short or longest for LEAST pressure drop) Now, going on thes calcs, it seems i have got it right, as for a given volume flowrate and pressure, a drop in temperature(the intercooler) increases mass flowrate and increases pressure drop for given pipe diameter and length. I assume this is why some guys have 2.5" to cooler and then 3" to plenum ??????? Any techos want to comment, ? .... Have i got it right ? Gary

I get this alot myself, its an unfortunate side of it . Charging peanuts is usually the problem. People treat you different if you are super cheap, they treat you just like your a mate helping out or something.... its weird, the less you charge , the more they expect and it attracts all the cheap arse idiots who dont have a clue (and think they do!). I learned this early on. Charge appropriately, and learn to say no if something is not up to scratch. And if they get the shits, then you dont want to deal with them anyway. As most decent people would know, if something costs you alot, you initially might cringe, however if you are happy with the result, then you soon forget the cost and are left with a smile that lasts alot longer than a cost saving initially. Confidence to charge appropriately is hard at first, depending on your personality, but you just have to get to that place where you do, else you get to the point where you are now and just throw it all away. I truly believe there is a niche for the backyard 'techo' guys to do work and tuning, as some guys like the personal service they get,dealing direct with someone rather than a workshop where there is usually not that friendly atmosphere where they feel more comfortable. Assuming your real good at what you do and take pride in your reputation (this alone will mean you go out of your way to do it right etc). They will keep coming back.... and word of mouth works well. Saying no will offend the idiots, and you might get a rep as abit arrogant, but then the idiots fade away and people who want quality generally will flow in...... takes a few years but it does work, at least for me. Hope you may reconsider ! Gary

Im currently doing lots of research into reflux stills to make my own ! As it will be years until its up north QLD. Reality is until lots of cars are E85 capable, it won't be prolific. I believe holden commodore is E85 in 2010 ???? This will be the catalyst i think , when the local cars can run it ..... can't wait. Gary

Are you saying the new guides you supplied somehow caused the head to crack ? ie too big or something ? Were they the wrong type ? just looking for abit more clarification Tangles Gary

Whats an AOD guys ? Some sort of lock up clutch in the converter ? Thats the best part of my jatco i think, and why i didnt mind going to 3500 stall. Once locked up, no difference in fuel ecconomy when crusing. Mike at MV autos said while i was talking about custom auto controllers, that i could try locking up the converter once in top gear at drags, . I was worried it wouldn't hold but he said it would. Said one of his customers had gained nearly 10 mph doing it ! Locking up the converter is also great for tuning the low end/light load on the dyno.... Without it though , thats where the mainline dynos rpm tracking is real handy !!! very handy feature when working with autos ! Gary

I was going to say, gee they look exactly like my LM-GT2's ... Thanks for the clarification MintR33 ! They are an awesome looking rim. I have them for my circuit racing, love the look... make the car look so much tougher than the VOLK multispoke rims i use for street... Gary

My god thats good value Darren !! awesome machine here guys, excellent for those with a family ! Best of both worlds. Gary

Oh i forgot to mention that in that spiel , thanks Darren. Yes i now know pressure is a problem, i too run an 044 pump i bought off of "Pump Daddy" off the forums here, however i suspect its faulty. The last dyno run i did last year when we discovered the new turbo and auto didn't add a kw extra, i had put a FP gague on and sure enough the FP topped out at 55psi on a 40 psi base, when running 20psi. So effectively have 35psi across injectors to your 43. which reduces there effective size to 496cc, plus it was running very rich, so that probably explains it.. When i got home, the pump was noisy as hell.... due to heat i assume , hasnt done it since. I have a new walbro sitting here waiting for me to get around to throwing it in. Plus i have to sort out a dual volt setup that allows full volts when 'full on' , for guilt-toy. I figured 550's should have been enough based on your results previously, and a few other guys around the 300 mark, however since i have sold my 550's (guys still isn't ready for them so i'm still running them) ,i figured i may as well buy some 740's. I'll get the pump in this weekend, as with the 740's and should be on dyno next week. I suspected the VG30 was out of puff, even with all the meat taken out of it, and hence why i went to a full turbonetics .63 housing.(and HKS cast mani) Time will tell i guess. I've got the option to go to the .8 later if this still isnt enough, however i sprint race the car mainly so i dont want to kill off bottom/mid any more as its already crap (full noise/boost at high 4000's).. Gary

Yeah i have found this too, going to a 2800 rpm converter dropped my mph from 118 to 113 ! , but ET dropped from mid 13's to 12.3 ! i now have a 3500 converter but yet to run strip. I only show 250 rwkw's and can't seem to get past it..... however my 550cc nismos are maxxed at 6000 rpm, so this gives me more of an indication of where i am at relative to others on here. (740's arrive tomorrow!) URAS, have you ever noticed on the R33 auto's, if you ramp them too slowly you get a big power dip just at the start of the run ?? The LINK i run has a rpm setting for cam on and cam off. I did notice if i turn it on to early it is noticibly harder to cruise up small hills, more throttle required, so i raised it to counter that, but the switch off has always been 6000, and i am ashamed to admit i haven't played with it yet when on dyno... will do now though as last run late last year i started noticing the top end dips ! Im chasing a problem of not being able to break thru 250rwkws. New larger turbo yeilded 250 same as previous, dropped exhaust BP from 7 to 3.2 (collapsed cat), nothing...250rwks....... its frustrating. I often wondered if the auto comp was playing silly buggers.... Dyno opens again next week, so i'll be back on soon to try new options (HKS cast mani and replace turbine housing with proper .63 turbonetics, rather than bored out VG30 one. And Ext gate + full 4" inlet to 4" pod (yet to be shielded, but just going for best soloution on dyno with bonnet up for now, until problem/restriction is found then will box properly for cold air.). Thanks for the info though, i really appreciate these posts where you guys show real data and measurements in your posts, great resource. Gary

Just saw this thread, and since i'm keen on a tig as i do abit of pipe work, i looked up the tig this guys uses..... holly cow, at Token Tools in AUS, there only $558 ! http://www.tokentoolroom.com/wsm200a.html Not bad for a home workshop. It doesn't look too cheesy from the pics.... might grab one ! Gary

Thats fine, as long as there part num RR544 at the end, i'll still take the 4 of them please. Gary

i'll take injectors, pm sent. Gary

Obviously not the std setup, but a custom setup would work fine. I'm about to swap out the 040 for a walbro over the chrissy break, so i will have a look at the wiring and work out a way to wire an external two stage setup triggering off the stock one and get back to you , with a drawing and all if anyone is keen. Obviously i can't say definitively what voltage the "low" setting has to be, until i get an idea what each pump needs to work at minium load setting, then i can reccomend a resistor to suit. I'll come back with some definate info later on. And if there is interest i can whip them up to ease install for those not into electronics/ electrical etc . Gary

For the record, my 040 intank has done the same.... noisy as hell after a dyno session and slow drive home..... its been quiet when cool. i guess since its submerged its cooled for longer, however the dyno session heated up the fuel alot . I'll wire the two stage back in, modified of course to provide full power when switched to direct. Gary

John at Turbo Supplies in Townsville did my Turbonetics front cover. Fair bit of work.... CNC machine would be nice once programmed. The slot inside sits just on the tip of the second smaller blades. Id post up a pic but at work. Gary

Just got the car back together this arvo and got it up and running again. Managed to get the full 4" intake and now using a 4" K&N filter. Will be cardboard fantasy'ing later on to come up with a box around it , then get it laser cut once looking nice. Also , currently got screamer, as i have to order a v-band 2" and flex joint to join back into exhaust. but thats changing too, as its 4" dump then welded onto chopped up end of original dump pipe for now. Later i will go 4" to Cat, then 3.5 back. Basically alot of small compromises in neatness (for my normal level anyhow) just to get it going again and to see if it all works ! It was good to hear it run finally .... but cops are rampant locally as its the season and all, so i though better of taking it out for some testing just yet..... So since it was still on jack stands i tried to stall it up.... Shame R33 rear brakes are shitty, as it wont lock fully, however i stayed on it and got to 10 psi and the gate cracked and holly shit........ Skyline lovers anywhere in a few blocks ears would have pricked up !!! haha Gary

The simplest way would be to reinvoke the factory system of lowering the pump voltage when not needed... this is obviously one of the reasons the factory do it in the first place, and we all go and rip it off. So way not use a spare output to controll your own setup of a relay and resistor. You could experiment with what size resistor will maintain the flow needed below your chosen rpm (since bosch flows more, it may need less volts at low revs than the stock pump needes to maintain pressure) ... A correctly working two stage system is the best soloution , no coolers required. Gary

a GTS LINK plug in still has knock retard , if its enabled. and it will pull timing out. And this resets once turned off, timing goes back to where it was. But i doubt this is your problem. Try reloading a new map in full, then modify to your specs , abit of a pain i know, however i recently had an old link giving me grief, and it turned out to be a corrupt map file. and even though i kept messing with it etc , the fault was still present..... a reload with another map solved problem (TPS was working in reverse !) So once i proved this i just adjusted maps to suit and parameters and it was all good.... Weird i know but i proved it by reloading original map and TPS was suddenly reversed again..... so worth a shot if you have hit a brick wall with other avenues. Gary

I agree with Guilt toy. The LINK Storm does a plug in for the R33 (i assume thats what you have ?) ... The Vi-Pec is a LINK customised to suit Ray Halls specs. Both work very well. And even if you keep the microtech, there is no excuse for not using the matrix mode, using the original single rpm load based mode is ludicrious. I know the Micros have there fan boys, especially rotarys, however from a tuners point of view, there really is alot better gear out there with finer resoloution and much better features that give you the opertunity to make the car drive alot nicer in all the areas between full power and idle !! And thats where you spend 90% of your driving time ! That being said, it still sounds like the Microtech isnt tuned well, and if your adamant about keeping it, im sure you could obtain a much better driving experience while still using it if it was tuned better. Gary

Im selling my VG30 Rear housing. Already got wastegate bored out and ported around it inside, however the housing is bored out to suit a T03 stage 3 garrett or turbonetics turbine wheel. PM if interested. Gary

i believe your microtech is an older MTX model without even "Matrix" mode ..... ie it has 15 odd load points , no rpm correction except WOT RPM off set ... and cruise corrections ..... IE Bloddy hard to make a nissan run nice with...... I currently run the original GTSLink also , but am awaiting arrival of the new G4 plugin to replace it. The new links are a pleasure to tune, and have some really great features..... Either way you wont know your car afterwards ! Terrific investment. Gary

Still a good result peter, got your sheet yet ? Now off to the drags to see if you can run a number ! Gary

Hmm more evidence R34's are alot more rear biased than R33..... thanks, Gary

yes there not overly roomy. I've never seen a legnum in the flesh but i asume there alot larger inside ... But then again its turbo'd..... and V6 ... do you really want to spend the money modding it (cmon you know it will happen) ... HPI guy is doing one currently i believe. Had to say whether to part out or sell, there value has dropped alot..... maybe try as is... cause its a weapon..... and well known... and would be good to keep a tuff 4 door auto around.... Yeah i just remembered Satanic has it now. Still pretty close Gary

No point revving above 6K anyway in stock form, powers already dropping off...