I thought i would update you guys on my mk2 golf, i used to run a hx35 with a 14cm hotside on an open manifold, I have since changed to a hy35 (10cm hotside) which reduced the spool about 500 or so rpm and i am now running E85 last weekend i was racing at santapod and managed to run a 10.63 @ 133mph with a 40 shot of nitrous. The terminal speed was the same as the hx35 with a 100 shot on petrol with the hy35 on e85 and a 40 shot so its making roughly the same power with a much smaller shot of nitrous.
Ooohhh, HX35G, fancy watercooled-ness. As dave said, there should be a number inside one of the scrolls on the twinscroll flange of the turbine housing. Looks to me like a 12cm, could be mistaken though.
What intercooler piping size are ppl running? I see 4" downpipe is the way to go for turbo response..wondering the pros and cons of running same size outlet intercooler piping vs 3" intercooler piping. I made 506whp on 3" piping, however, response wasnt super great. I would like to reduce to same outlet size from turbo...just concerned i might lose power.
Stolen this from DSMTuners, not sure how much of it is 100% accurate but the maths seems okay? Start copypasta - *.4 Mach is the point at which air becomes turbulent and losses in efficiency start to occur exponentially. The key is to stay under that speed. You want to use the smallest piping possible that still flows enough to meet your needs. Larger than necessary piping increases lag time with no measurable gain The velocities are in miles per hour and mach, and the flow rates are in cfm. Measurements for the piping are in inches. 2" piping 1.57 x 2 = 3.14 sq in 300 cfm = 156 mph = 0.20 mach 400 cfm = 208 mph = 0.27 mach 500 cfm = 261 mph = 0.34 mach 585 cfm max = 304 mph = 0.40 mach 2.25" piping 3.9740625 sq in = 1.98703125 x 2 300 cfm = 123 mph = 0.16 mach 400 cfm = 164 mph = 0.21 mach 500 cfm = 205 mph = 0.26 mach 600 cfm = 247 mph = 0.32 mach 700 cfm = 288 mph = 0.37 mach 740 cfm max = 304 mph = 0.40 mach 2.5" piping 4.90625 sq in = 2.453125 x 2 300 cfm = 100 mph = 0.13 mach 400 cfm = 133 mph = 0.17 mach 500 cfm = 166 mph = 0.21 mach 600 cfm = 200 mph = 0.26 mach 700 cfm = 233 mph = 0.30 mach 800 cfm = 266 mph = 0.34 mach 900 cfm = 300 mph = 0.39 mach 913 cfm max = 304 mph = 0.40 mach 2.75" piping 5.9365625 sq in = 2.96828125 x 2 300 cfm = 82 mph = 0.10 mach 400 cfm = 110 mph = 0.14 mach 500 cfm = 137 mph = 0.17 mach 600 cfm = 165 mph = 0.21 mach 700 cfm = 192 mph = 0.25 mach 800 cfm = 220 mph = 0.28 mach 900 cfm = 248 mph = 0.32 mach 1000 cfm = 275 mph = 0.36 mach 1100 cfm max = 303 mph = 0.40 mach 3.0" piping 7.065 sq in = 3.5325 x 2 300 cfm = 69 mph = 0.09 mach 400 cfm = 92 mph = 0.12 mach 500 cfm = 115 mph = 0.15 mach 600 cfm = 138 mph = 0.18 mach 700 cfm = 162 mph = 0.21 mach 800 cfm = 185 mph = 0.24 mach 900 cfm = 208 mph = 0.27 mach 1000 cfm = 231 mph = 0.30 mach 1100 cfm = 254 cfm = 0.33 mach 1200 cfm = 277 mph = 0.36 mach 1300 cfm max= 301 mph = 0.39 mach In order to convert from Lb/Min to CFM for the equation above, you take the flow rate in Lb/Min for your turbo (generally an educated guess based on the pressure ratio and power created) and multiply it by 14.27. That will yield the CFM flow for your setup. For Example: T3/T04e 57trim .63ar @ 21psi makes 452 whp This turbo is known to have a 50lb/min compressor wheel which will make ~500bhp. Since we're using whp above, we can assume this turbo is pretty close to its max of 50lb/min. Now to convert that to CFM, you take 50lb/min x 14.27 = 713.5 CFM. When you refer to the table above, you can see that we're starting to max 2.25" piping, but we're still in the "good" range for 2.5" but it also depends on how smooth the piping is inside... and all the bends. this i would say is " perfect piping conditions" and if you would pick a number to upsize your piping at it would be when you hit about the .3 maximum .35 mach region. - End copypasta Personally, I wouldn't have thought there was a monumental amount of response to be gained from stepping down intercooler pipe sizes. It does look to improve the air's velocity by a decent amount, but whether that would in turn equal a noticeable "response" change is something I wouldn't know enough about to comment on. I haven't seen any testing done on this either, just maths and theories. Perhaps Stav could comment or share knowledge on the matter, as I'm sure he would be better equipped to inform you than I would.
Hey guys. Holset hx32w with 12cm twin scroll housing. How does that compare to the likes of a hx35 or hy35 on a 1jz? Just curious. {}
Pretty good option tbh. If you've got a twin scroll manifold then it's ideal, but even if not it'd still work really well. Some may say slightly undersized, but the 12cm turbine housing will flow well up top. Anymore photos? Are you going to keep it internally gated?
Will work well dude, as Ben said a twinscroll manifold would help spool but cheapest option for better response is a 3.5 or 4" downpipe. It's pretty much in between a HY35 and HX35
Ok cool. I don’t think I have room for any more than a 3” downpipe and I’m on a japspeed 1jz vvti manifold with a eBay 44mm gate. I think I’m going to keep it on the shelf until I can afford standalone. Currently I’m on emanage blue but I can’t really find anyone to map it on my current setup.
Update. Had the car setup and the results aren't great. Certainly not what I was expecting. Any ideas on why it could be so laggy? {} {}
