Just starting a thread to discuss turbo/fuel/intercooler selection and theories. Some base information.. http://community.asiaosc.org/~zaliman/TurboSelector.htm Outlet CFM × Density Ratio = Actual Inlet CFM Using the same 350 in our examples, it would look like this: 516.5 CFM × 1.37 = 707.6 CFM Inlet Air Flow That is about a 37% increase in airflow and the potential for 37% more power. When comparing to a compressor flow map that is in Pounds per Minute (lbs/min), multiply CFM by 0.069 to convert CFM to lbs/min. 707.6 CFM × 0.069 = 48.8 lbs/min Now you can use these formula's along with flow maps to select a compressor to match your engine. You should play with a few adiabatic efficiency numbers and pressure ratios to get good results. For twin turbo's, remember that each turbo will only flow 1/2 the total airflow. Last updated 12/28/02 Turbo Type ----------- Approx flow @ pressure Stock Turbo ---------- 360 CFM at 14.7 PSI IHI VF 25 ------------- 370 CFM at 14.7 PSI IHI VF 26 ------------- 390 CFM at 14.7 PSI T3 60 trim ----------- 400 CFM at 14.7 PSI IHI VF 27 ------------- 400 CFM at 14.7 PSI IHI VF 24/28/29 ----- 410 CFM at 14.7 PSI ========= 422 CFM max flow for a 2 Liter at .85 VE pressure ratio 2.0 (14.7 PSI) 7000 RPM ======= IHI VF 23 ------------- 423 CFM at 14.7 PSI FP STOCK HYBRID -- 430 CFM at 14.7 PSI IHI VF-30 ------------- 435 CFM at 14.7 PSI SR 30 ----------------- 435 CFM at 14.7 PSI IHI VF-22 ------------ 440 CFM at 14.7 PSI T04E 40 trim -------- 460 CFM at 14.7 PSI ========= 464 CFM max flow for a 2.2 Liter at .85 VE pressure ratio 2.0 (14.7 PSI) 7000 rpm ======= PE1818 -------------- 490 CFM at 14.7 PSI Small 16G ------------ 505 CFM at 14.7 PSI ION Spec (stg 0) --- 525 CFM at 14.7 PSI ========= 526 CFM max flow for a 2.5 Liter at .85 VE pressure ratio 2.0 (14.7 PSI) 7000 RPM ======= Large 16G ----------- 550 CFM at 14.7 PSI SR 40 ----------------- 595 CFM at 14.7 PSI 18G ------------------- 600 CFM at 14.7 PSI PE 1820 -------------- 630 CFM at 14.7 PSI 20G ------------------ 650 CFM at 14.7 PSI SR 50 ---------------- 710 CFM at 14.7 PSI GT-30 ---------------- 725 CFM at 14.7 PSI 60-1 ----------------- 725 CFM at 14.7 PSI GT-35R -------------- 820 CFM at 14.7 PSI T72 ------------------ 920 CFM at 14.7 PSI <--- Note you would have to spin a 2.0 L engine at about 14,000 rpm to flow this much air. IHI VF 25 ----------- 395 CFM at 18 PSI IHI VF 26 ----------- 400 CFM at 18 PSI T3 60 trim ---------- 410 CFM at 20 PSI IHI VF 27 ----------- 420 CFM at 18 PSI IHI VF 24/28/29 -- 425 CFM at 18 PSI IHI VF 23 ----------- 430 CFM at 18 PSI IHI VF-30 ----------- 460 CFM at 18.0 PSI AVO 320HP -------- 465 CFM at 17.5 PSI T04E 40 trim ------ 465 CFM at 22 PSI FP STOCK HYBRID- 490 CFM at 18.0 PSI IHI VF-22 ---------- 490 CFM at 18.0 PSI SR 30 --------------- 490 CFM at 22 PSI Small 16G ---------- 490 CFM at 22 PSI ION Spec (stg 0) - 500 CFM at 19 PSI PE1818 ------------ 515 CFM at 22 PSI Large 16G --------- 520 CFM at 22 PSI ========= 526 CFM max flow for a 2 Liter at .85 VE pressure ratio 2.5 (22 PSI) 7000 rpm ======= ========= 578 CFM max flow for a 2.2 Liter at .85 VE pressure ratio 2.5 (22 PSI) 7000 rpm ======= HKS GT2835 ------- 580 CFM at 22 PSI 400 hp MRT 400 ------------ 580 CFM at 16 PSI AVO 400HP -------- 580 CFM at 17.5 PSI MRT 450 ------------ 650 CFM at 19 PSI AVO 450HP -------- 650 CFM at 20.0 PSI SR 40 ---------------- 650 CFM at 22 PSI ========= 658 CFM max flow for a 2.5 Liter at .85 VE pressure ratio 2.5 (22 PSI) 7000 rpm ======= HKS GT3037 ------ 670 CFM at 22 PSI 460 hp PE 1820 ----------- 680 CFM at 22 PSI 20G ---------------- 695 CFM at 20.0 PSI HKS GT3040 ----- 710 CFM at 22 PSI 490 hp AVO 500HP ------ 770 CFM at 22 PSI SR 50 ------------- 770 CFM at 22 PSI GT-30 ------------- 790 CFM at 22 PSI 60-1 --------------- 800 CFM at 22 PSI HKS GT3240 ----- 830 CFM at 22 PSI 570 hp GT-35R ----------- 880 CFM at 22 PSI T72 --------------- 1000 CFM at 22 PSI <--- note you would have to run a 2.0 L engine at >40 PSI boost to flow this much air Conversions used where there was control over conversion factors: 1 HP approx equals 1.45 CFM 1 CFM approx equals 0.0745 lb of air/min 0.108 Lb/min approx equals 1 hp 1 Meter cubed/sec = 35.314 CFS = 2118.867 CFM 1 KG/sec = 132 lbs/min approx equals 1771.812 CFM power coversions: 1 PS = 0.9859 HP = 75 Kgf m/sec 1.3405 HP = 1 KW 1 HP = 746 watts TMIC Intercooler information. Stock WRX 390 CFM TurboXS: 635 CFM MRT: 650 CFM Spearco:1000 CFM FMIC APS seems to number there intercoolers near approximate CFM 500-650-750. As most can see the Stock WRX intercooler is perfect match for the stock turbo as well as leaving a smidge of headroom on the table. Naturally there is efficency/Pressure Drop, core design and ability to shed heat which are not apart of this formula. So while a Spearco TMIC has enough CFM for a T-70, it may not be efficent at cooling the charge, on a hot atl day, but on a normal michigan day, or while on the move, it would do very well. Likewise there are many many 20g's that are fine and dandy on larger top mounts. Pick the appropiate one and pull the trigger, there is more to it and proally some wrong info here, so correct if needed. Exhaust Housing Theory..... Most of my knowlege is on DSM's as far as turbos go, but I rarely see mention of Exhaust housing size. Most upgraded turbos are going to be 7cm housings. I feel that the 7cm Housing offered on the non-rotated setups are not the most optimal for a larger turbo 20g+, whereas a good option for an EVO would be a 10.5 Housing of a TME. When planning, out the car, I felt there is a problem with exhaust turbluence with larger turbos reinforced by EWG power gains that were insane. To Start the main fix for this is the External Gate. This bypasses this problem and reduces turbulence, resulting in a FAT gain. What about those of us who do not wish to go external.. How can we reduce this preturbine backpressure in the turbo.... Respected Tuner Clark Says... In most cases on subaru's clipping actually decreases spool. One car gained 40-50ft lbs in the middle with nothing changed but a clip. Most turbine options for the EJ motor are way, way to small choking off power and running a large Exhaust gas presssure ratio before the turbine. Clipping increases flow, reduces pressure and makes more power. This is one of those things that points out that an EJ motor is really different then an inline 4. On large turbos I think this is much more of a problem So the options are 8cm housing, or a Clip to reduce backpressure.. One is available only by greddy, the other deadbolt can hook you up with To see if you have problems with pre-turbine backpressure you can fab a pressure gauge to run off your EGT bung in your upipe (Where most ewg mounts huh) Maybe tommorow some fuel discussion ^_^ DiscusS!!! Jason
Damn! I'll be reading this while I'm at work today. This is actually most interesting, I am curious to see more information about clipping of the turbo fins and the alleviation of backpressure.
Thanks all, Bored again tonight at work, so I will go ahead and talk about engine cooling and importance for these upgrades on WRX-STI. During this part there are a few things that are important to know.. Our EJ Series 2.0 and 2.5 engines are of an aluminum design, unlike the EVO and other cars which use a Cast-Iron block, which are less sensitive to warping/detonation/egt Around Temps of 115c+ there is a possibility of head warping, which no one wants or likes Its important to some degree to monitor your water temperature on more heavily modified cars. Here is how the stock water temp gauge works on most 2002+ Subarus From Service Manual When the coolant is at a normal operating temperature of approx. 70 to 100°C (158 to 212°F), the guage's needle stays in the middle of the indication range as shown below. It then gives a graph with the X-axis labelled "Temperature (°C)" and the Y-axis labelled "Indication." From 50 to about 70°C the graph rises with a slope slightly less than 1. From about 70 to 100°C, the slope is just slightly above 0. And from about 100 to 120°C, the slope is slightly above 1. 120°C corresponds to the start of the red area on the temp guage. What does this mean? Well for one once you hit Red you are at engine damaging levels.... Also, consider this, if you were to lose all of your coolant, the gauge is going to only read the TEMP of the air/steam/remaining coolant passing over the stock sensor, sans visual inspection you would have no way of telling. A dangerous example..... Wrxatlanta member is driving to a track event slowly losing coolant, the said driver feels secure knowing he must look down and would think losing coolant equals high temps. As he drives the meter doesnt move due to the alternating temp of steam/coolant that remains in the system passing over the sensor. Thinking its safe, the said driver blasts from 15mph-85mph enjoying his on ramp merge, this time enough could cause engine damage if not closely monitored. Seeing that the temp sensor may be at the bottom half of the block were the coolant pools, as is the themostat, the top half of the system may be all steam/evaporated water or none at all (HEADS/TURBO). Damage ensues... Keep an Eye on your levels! So for a healthy car it is always wise to increase reserve. Does 20% more horsepower not worthy of 20% more cooling capacity? So there are a lot of ways to reduce this we will start with the water side of cooling, and then the oil side of cooling. These two will be related more often than not. The main reason is the following. Turbocharger=Air/Oil Cooled. STI/WRX comes equiped with a water cooled oil cooler right where you screw your oil filter in. Reducing one will generally result in a change in the other, how much? Havent tested yet, but people with oil coolers only notice their water temps are a smidge lower and people with upgraded coolant systems notice slightly lower oil temperatures. So Cooling whats good and not Options 160 Thermostat:The main thing this will do is help lower the recovery time of coolant to a normal degree. Also a bonus is the ability to fail open. Upgraded Radiator:Increases the cooling capacity of your system, as well as efficiency depending on core, design and dimensions. Fans:Can increase the airflow over the radiator, usually most aftermarket fans will do no better than stock. The main selling point is the running options of the fans, you can set them to come on at an eariler temperature, always on, manually on, however you wish. Coolant Mixtures:Youve heard about these. Water Wetter, 20% Coolant/Water mix etc. I will leave this best set to you, here in summer however I run water wetter, and a 20%/80% mix for summer. Warning:Water Wetter breaks down rather quickly and starts to loose its effectiveness. Its always best to change your coolant on a seasonal basis. Dont forget the Subaru Conditioner(opinion) So what other benefits/results can come from this. Well first, cooling upgrades make ZERO horsepower. They add piece of mind, and recovery. A cooler engine is a more lasting engine, and is less prone to detonate. Here are some results from various testing done over time. How I tested the Tstat on my WRX at the time running around 325whp on the dyno dynamics: I sat and idled until I reached temp stabilized. With the stock Tstat this was around 88-89C as reported by delta dash. I then ran through the first 3 gears at WOT and pulled over while running data logs with delta dash. I forgot my dang Delta dash Key today so I cant post these logs. But here are the start and ending temps: Stock Tstat: start of test 88C at idle. End of test 102C with a rise 20 seconds later to 105C. Time back to 88C was 3 minutes at idle. Steady state cruise on highway 85C Crucial Tstat: Start of test 82C End of test 85C A rise to 87C after 20 seconds. Time back to 82C was 1.5 minutes. Steady state cruise on highway 76C This car as a PWR radiator, Samco Radiator hoses and a 50/50 mix of coolant and water. Stock fans. A cooler engine is less prone to detonate. A hotter engine normally runs cleaner and is more effecient. A cooler engine will probably last longer and it will certainly raise the detonation threashold of the engine. A leaner AFR can probably be run and or more boost. High HP WRX's can get over 105C on long pulls. A single Dyno pull on a 400whp WRX will have a rise of 15-20 degrees. Some further data. http://importdesigns.com/datalog/160tstat.html So the main worry about a colder thermostat is engine warmup. Its ok, the ECU stops fuel enrichment for cold start at 60c or 140F, (Well below the 160 themostat temp)which you will not see often unless it is cold cold wintertime. (IF you feel its time to change the coolant anyway, grab that stock thermo if ya feel, but not necessary) So definately a worthy mod for your car if only for the reduced coolant recovery times. ----Colder Plugs---- What they do:Reduce chance for pre-iginition. How they do this: Dissipate electrode heat to the heat, reducing in a cooler plug tip(I.E not so hot it lights off the incoming fuel mix before spark). Why is the cooler spark tip good? It is possible for the tip of the plug to get so hot it will set off the combustion mixture prematurely causing preignition. Definitions and Causes: http://www.hastingsmfg.com/Service Tips/detonation_and_preignition.htm For us STi owners this is somewhat an issue as the ringlands on the 2.5 are not at all kind to any kind of Detonation or Otherwise. Nor is it a cheap fix. Example: http://forums.nasioc.com/forums/showthread.php?t=739894&highlight=ringland
From Howstuff Works as a starter. Clipping is the technique of cutting away some of the material on the fins of the impeller wheel of the turbocharger. In other words, to 'clip' a turbo is to make the fins in the exhaust path smaller. The cut is usually done at an angle of between 10 and 20 degrees - the bigger the angle, the more material is removed from the fins. This may seem like a dumb thing to do, since smaller fins mean that the exhaust gases will impart less force to the turbine wheel and consequently increase turbo lag. This is true, but the benefit of clipping is found in the high RPM range of the motor. At higher RPMs, the turbo may have already surpassed the required user-set boost levels and is not contributing to engine power. Since the impeller wheel in the exhaust stream partially blocks the exhaust gas flow (by design), it can act as a significant restriction at high RPMs, when the exhaust flow rate is highest. Clipping the turbo reduces this restriction and allows more air to flow past the turbo wheel at high RPMs, thereby improving airflow through the engine and increasing top-end response Which btw, Jerry annouced maybe two days ago the future return of 8cm housings. TEC has as well, announced there 8cm turbo housing on nasioc yesterday! Hope, im curious to see if this is a big power maker. Anyas the possible cause of the backpressure is due to unavoidable runner length and boxer design. 1-3-2-4 Firing Order 1-3: Drivers Side Cyl. 2-4assengers Side Cyl. So that being said the 1-3 pulse fires, immedately hits uppipe, then 2-4 fires, travels across the runner and then goes up the uppipe, to the turbo. Basically the turbo spins up charged by the first gas pulse 1-3 at ??? %throttle, waits, slows by X amount, and is slammed by a most likely different velocity exhaust pulse spinning it back up from cyl 3-4 direction. This process repeats. So as a lame example if you were to take a pinwheel and blow a steady stream of air the wheel spin will be smoother more predictible. No see if you can achieve the same smooth spin by taking puffs at the wheel. Most likely it will not be the same. (Now for clipping, imagine you were able to change the angle of the fins on the pinwheel) I wont get into gains/losses of headers as some like some loathe so thats between you and tuner/expert/what you want.. Subaru has seen fit to equip Spec C with Equal Length header, and most JDM STi (all with twin scroll which isnt offered here) "The unique twin-scroll equal length manifold now joins cyl. #1 with #2 and #3 with #4 to reduce exhaust pulse interference and ensure maximum exhaust energy is available to spin the turbo" Im not a big fan of the non-equal length sound nor do I own any equal length header, but interesting none-the-less. Yummy Equal/Wierd Sound: http://www.boomplustoys.net/Fujitsubo/images/superex/gda-01.jpg Avg Unequal(2 crosspipe paths) Aftermarket/Boxer Rumble!: http://images.channeladvisor.com/Sell/SSProfiles/10056586/Images/Img_0004.jpg Stock!(single cross pipe/Recommended due to Heat retention/EG velocity by most) http://putfile.com/pic.php?pic=6/15804355750.jpg&s=x2 As always Standard disclaimer, this is just me rambling, and not any kinda fact fact fact!
I'm interested in crucial racing Cooling package. Does "shroud" really work?? or is it just bling bling factor???
You know I have a shroud but I couldnt tell you for a fact if it works. If anything it makes a neat heat sink for the radiator if its made of metal, but its supposed to direct air, not increase surface area for cooling but either way if its >$50 couldnt hurt.. No proven results I could give you.
interesting write up on the headers, not sure though if I could go without the boxer sound. Although, a plus, from what Ive read about some of hte high end headers avail, people are putting out sounds similar to race bikes or such (more bass).
You know, there is a new product that I wish I could go back and try on the headers. It would retain most of the cast iron parts and replace the worst part of the header. Its the Injen Crossover pipe. Coating the center pipe wouldnt be much and probably the best of both worlds.
^^^^ Does that just join the left and right exhaust manifolds? I dont know anything about headers . . .
holy 230 for a pipe batman! http://store.newlevelmotorsports.com/02crpiwrwa.html can anyone find the diamiter of the new pipe? heres more info from club wrx info ill post more as i find it! i might get one made for me. anyone got a stock header crosspipe laying around that i can get the flanges from?
Off topic So I drive a 02 Rex, the suby dealer put a new 05 tranny in and new front axles to fit, and and gave it back to me.. Well drove the Rex 2k miles and boom clutch goes out.. Fly wheel and everything. So shouldn't they replace the clutch with a 05? By the way costing 1,500$.. Hmm