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@Turblown@RGHTBrainDesign I'm SURE you guys have some fast intake temp data on single turbo FD's with Greddy Vmounts. Does the intercooler cool enough, or is it pretty sub par with the likes of a S362SX-E pushing 450-500hp?
The reason for the low power is CRAZY high IATs is because stock intercooler and SUPER lazy timing (on purpose) It will make over 400 EASILY once it has a decent IAT. (we use Dynapack same as you just the bigger pods) (yes I'm crazy and tried a dyno run with the stock intercooler, IAT went from 38C at the start to 78C at the end of the run in 4th gear 16-17psi at 8-9 degrees timing) Poor 13B eh.
Rice Racing in one of his diatribes elsewhere years ago mentioned seeing a consistent 85C with the ducted SP smic when running the twins on a warm day over here, maybe not that remarkable. I haven't seen him post elsewhere in recent years - without getting the ban stick soon after - but with the progression of various singles and pre-turbo injection, was still running that smic (for originality! ) last I saw.
Originally Posted by coupe-r
Reason for me not going vinny fab is the 5k NZD price tag
Must be screwing the home market, all varieties, seem to be shown as 1k Au, maybe the kiwi has dropped off a cliff recently.....plazmaman might return the favour going the opposite way!
When the greddys got popularised ~10/12 years ago, I thought the main selling point was a bolt-in kit for those who didn't have the ability or facilities to roll there own - seems you can, no brainer if you want something better I would have thought? If rx72c is around, maybe he kept logs from this 8474 set-up https://www.rx7club.com/build-thread...1047574/page2/
I would have to do some digging, I haven't personally been tuning cars for a good 7+ years ( only really step in for big ones for fun). We are also the busiest we've ever been, so I really don't have the time unfortunately.
One of the big problems with these vmounts is the end tanks I believe. They just don't distribute flow well enough, and there is some serious turbulence at high boost. Most of the Vmount end tanks literally are pointing the airflow at the flat bottom side, its my suspicion that this is why a lot of FMIC cars make more peak power usually. We've been working on a fix for this, and will be documenting pressure drops/air temp difference with a back to back dyno against a similar core in roughly 30 days when the molds are finished. I've show a few of the edits off on our social media.
Regarding the end tank design, funny thing is Greddy is prob one of the BETTER vmount tanks design with it being a nice cast flow. But yes still against the back side of the cooler vs across it. Plenty of the front mounts on FD actually have the same end tank flow direction with em angled straight up off the back side.
I have my doubts if this is a HUGE issue regarding cooling and performance but be interesting to see your tests. You would be surprised at what boost fixes haha
Another way to look at this is, am I really going to fit THAT much of a bigger/better core design in there if I make it myself?
I could prob get another 20% size MAX out of it if I want to fit a cold air filter on the side, even then it's hard to find high quality tube and fin in the correct size. Bar and plate is everywhere, Garret cores etc.
I thought the main selling point was a bolt-in kit for those who didn't have the ability or facilities to roll there own - seems you can, no brainer if you want something better I would have thought? If rx72c is around, maybe he kept logs from this 8474 set-up
Its a time thing, I need to call in favours for fab work from friends and by time its done, will take longer and prob similar cost to if I just bought the Greddy kit.
Realised this thread was getting boring so here is the dyno vid.
385hp at 7030rpm, 430.5Nm at 5840
Borg Warner S362SX-E 1.0 A/R
Cast stainless sch10 manifold, twin Turbosmart compgate 40 plummed back into 4" Down pipe, then into 3" CAT back exhaust (no cat)
13B engine of unknown build but looks to be mild street port when checked in the runners.
Stock intercooler with cobbled together temporary piping.
stock 9 trailing plugs all round on stock coils.
Stock 550cc primaries with 1600cc secondaries.
AEM 340LPH pump on stock wiring with resistor bypassed (still low 11.5volts at pump but ZERO pressure drop at this power and boost level)
Boost wasn't controlled very well with the power FC on that run (didn't have it dialled in correctly) was targeting 18psi (only hit that at 5800 or where the max torque is) dropping off to 16.4psi at peak power.
38C at the start of the run increasing to 78C. Dyno RPM limit set to 7800rpm.
Mild misfires from 6500rpm on due to spark. (have a twin power to go on)
No knock at all.
Lazy 8-9 degree timing 10.6-11:1 A/R area.
I'm sure there are modest end tank shock loss/turbulence effects but if you look at the transition from end tanks into and out of the core tubes it seems a bit silly to get too obsessive at least on the intake side. As smooth radii into and out of pipes as you can, beyond that there has to be massive velocity changes at the core interface anyway.
The contouring of IC end tanks (like the HKS V-mount core shown) is only to reduce VOLUME for the transient response benifits and fit the largest core in given area.
There is NO benifit but conversely a detrement in trying to maintain laminar flow from the end tank into the IC core and huge benifit to the opposite of introducing turbulence on the inlet and easing transition of turbulent back to laminar flow for the outlet.
You will see OEM end tanks often have shapes to reduce volume while evenly distributing flow and internal features (dividers/walls) to trip flow to turbulent flow to make it easier to penetrate the core.
That's a good observation but I think it's worth considering/noting that the climate around Tsukuba is also generally pretty cool. Especially in February which is when the major Attack event is held. Temps during that time seem to average a low/high of 34°F - 49°F. The car in this example is also still tt. You can see the intake for the second turbo between the brake booster and intake manifold. Not that the intake air temp issue is reserved for single turbo cars..
Sidebar -- it's pretty incredible that RE built an FD that runs a 56.xx Tsukuba lap on stock twins, though. That's flying
Above the exhaust manifold is an even worse place heat-wise than behind the intercooler. Good point about the climate.
Extended side-bar: This car is also currently for sale, $80k landed in the USA. Would be really cool to have, more exciting to see than a Spirit R car for me at least.
Sidebar -- it's pretty incredible that RE built an FD that runs a 56.xx Tsukuba lap on stock twins, though. That's flying
its interesting, to me that you can do sub 2 minute laps with pretty mild engines. its probably that a broad powerband has more average power than something peaky
the Super Now! FC was under 2 minutes with a stock turbo FC engine, which is really nuts, maybe 240rwhp?
apparently that intercooler is a pair of Cx5 cores, which is also interesting
Can anyone with a Fast acting IAT and a greddy vmount please comment on their IAT increase above ambient? Ideally someone pushing some decent HP and boost through a smaller SX-E turbo (S362 etc) 16-20psi area 400-500hp.
FYI- There was a car on BAT just today that didn't sell but it has:
Borgwarner S362 turbocharger
GREDDY cooling fans and v-mount intercooler
Is pushing 500RWHP
The car was built by IRP and there is a dyno sheet uploaded to the auction. So if I we're you, I would give them a call and get a reliable answer.
The reason for the low power is CRAZY high IATs is because stock intercooler....
Damn...The stock IC is inadequate even for a stock twin turbo car.
I say that because back in the day a buddy of mine's FD was pretty much stock, his only mods were intake, DP, and a tuned power FC. Anyway, on a 25C day we did a couple of pulls and his IAT's soared to 65-70C. And pretty much stayed heat soaked for like an eternity.
In contrast, I had a PFS smic and my temps after a few pulls raised from low 40's to 50C and stayed there until I let it cool (which also took a long time but that's the nature of the SMIC). These days, I love my greddy vmount. A heat soaked IC is a thing of the past for me.
The GReddy v-mount is ubiquitous enough now, where someone should make a carbon intake box that seals the passenger side hole, and leaves the back customizable for the turbo you have, and/or make it for popular setups like the Turblown shorty.
It's fundamentally a bad idea to suck in hot air from behind the intercooler. You want to feed the turbo with the coldest, and most DENSE air possible.
Many people just think of air temperature without considering density. They believe that the difference between 90*F and 120*F isn't huge when the compressed air can see well over 300*F before dropping to less than half of that, and their belief that a bigger intercooler will bring that final air intake temp down lower than if they sucked in 30*F cooler air and lost over 30*F of intercooler temperature reduction ability.
AIR DENSITY needs to be considered. Hotter air is less dense. A turbo compresses the amount of air molecules that it takes in. Feed it hotter and less dense air, and your compressed air has less air molecules than it would otherwise.
You can have 90*F air intake temps in Denver, Colorado and make less horsepower than 120*F turbo intake temps in Florida.
The base of Pikes Peak can be 80*F while the summit can be 30*F. Due to the less dense air at the summit, cars will always make significantly less power than they would at the base, even if the turbo inlet temps are 50*F higher. This is because the turbo is sucking in far less air molecules despite the intercooler seeing 50*F colder air temps to cool off the compressed charged air.
Don't be lazy and slap air filters on behind your intercooler. Feed your turbo with the coldest air possible.
Re-Amemiya RX-7:
It's not that hard to turn Sub-1s at Tsukuba with decent tires and a little aero. The Re-Amemiya car with twins might be making 350-400whp+ which would make that lap time fairly easy to achieve. Also, many Japanese Time Attack cars do goofy things that are NOT right/better/good/fast. So I would take whatever you see with a grain of salt and not view everything they do as gospel.
Last edited by Billj747; May 11, 2024 at 12:47 AM.
The coolest air possible would be best, but not if getting it causes restriction. If you create a low pressure area at the turbo inlet from restriction you are raising the pressure ratio the turbo is working at for the same peak boost which adds heat.
Just adding a velocity stack to an otherwise unrestricted turbo inlet pipe can reduce the low pressure at turbo inlet and increase spool and power noticeably. I did the data logging back when I did it.
Next point. 400rwhp is around 60lbs/min air into the turbo. Thats about 800 cubic feet a min or 13 cubic feet a second and your engine bay is going to have about 6 cubic feet of air space. Which is exactly why heat soak from idling at a stop clears up so fast once you start boosting.
Think about it from your own experience. you heatsoak at a stop with the car feeling sluggish and then boost your car (which should add heat) and temps come down fast instead of going up.
Last point is efficiency of heat exchangers. The IC and radiator can only transfer so much heat into the air passing through. When he vehicle is moving at speed there is a LOT of air flow through the heat exchangers with a small increase in temperature of each cubic foot of air.
A race car that has timed laps from a flying start isnt going to benifit from cold air intake like a car stuck in traffic and trying to race off a red light would.
Good points on inlet restrictions and pressure ratios, but I disagree on your last sentence. Road rce cars greatly benefit from getting cold air to the intake, which is even more important when interfoolers, engines, radiators, and the entire cooling system heat soaks and reaches an equilibrium (often insufficient for many builds) after many minutes of running at full throttle.
To add even more variables, you mentioned the engine bay is only 6 cubic feet. If the turbo is open to the engine bay and creates a low pressure area in the engine bay, then your pressure ratio goes down, and so does your power. A well designed vented hood creates lower pressure to extract air from the engine bay and radiator, which also makes a post-intercooler air filter result in less power.
On a dyno with the hood open, most turbos benefit from poorly placed intakes and you'll see gains from reducing the inlet restriction by doing things that will greatly hurt your power in practice, with the hood closed and the car actually moving.
You want the coldest and highest pressure possible for the turbo inlet. You also need to instrument and look at the results with the car moving and not from static dyno results.
Because of this, I've always liked V-mounts where the turbo, intercooler, and radiator get ambient, high pressure air (when ducted properly) vs fmics which increase the temps and reduce pressure to the radiator and turbo inlet (unless the turbo is ducted to a removed headlight).
It's not that hard to turn Sub-1s at Tsukuba with decent tires and a little aero. The Re-Amemiya car with twins might be making 350-400whp+ which would make that lap time fairly easy to achieve. Also, many Japanese Time Attack cars do goofy things that are NOT right/better/good/fast. So I would take whatever you see with a grain of salt and not view everything they do as gospel.
Generally speaking I agree this is a fair/good/smart perspective to maintain. Particularly regarding some of the weird tactics used/tried there. At the same time, at Tsukuba, there is a big difference in difficulty within the 3 to 4 seconds that separate a less than 1min lap and a 56 second lap. I dug a little more and that RE car has the 71st fastest lap at Tsukuba overall, clocking a 56.094 and there are 19 RX7s that have done a faster lap. Seems pretty impressive to me.
56 second Tsukuba car, for sale built by Re-Amemiya as a Demo car. They seem to believe the larger intercooler vs CAI is the way to go.
I tried looking this car up and couldn't find it doing a 0:56 at Tsukuba. Do you have a link?
Originally Posted by cloud9
Generally speaking I agree this is a fair/good/smart perspective to maintain. Particularly regarding some of the weird tactics used/tried there. At the same time, at Tsukuba, there is a big difference in difficulty within the 3 to 4 seconds that separate a less than 1min lap and a 56 second lap. I dug a little more and that RE car has the 71st fastest lap at Tsukuba overall, clocking a 56.094 and there are 19 RX7s that have done a faster lap. Seems pretty impressive to me.
Do you have a link to that particular car's 0:56 or where the RE car being ranked 71st? I would guess there are more lap times than are on whatever list that is.
Many people have said a 1:00 lap at Tsukuba is comparable to a 2:00 at Buttonwillow in California. Heck, a stock powered BRZ/GT86 with tires and a little aero can do Sub-1 at Tsukuba and Sub-2 at Buttonwillow. Neither of which is that difficult to accomplish.
A stock GT86 makes half the horsepower that stock/modified twin turbos can make in an FD. Therefore, a stripped time attack car with good tires and a lot of aero with twice the whp of a stock GT86 (that is capable of a Sub-1 at Tskukuba) isn't all that difficult.
^^^Might be waiting a while, looks like he's been a bad boy!
Does "demo car" mean a tribute replica or the genuine article?
This appears to be the vehicle 車両. If it's LW, it suggests it should be under 1000kg/2200lb, with more tyre, running 050 softs(?), assuming same track conditions, matching the earlier car that did 56s with 50hp more, I guess is possible......and the PFC suggests it was running twins. Funnily enough, to get back to the OP's original discussion, the IC set-up they are flogging that is named in the spec https://www.rhdjapan.com/re-amemiya-...-kit-fd3s.html doesn't quite match the thing that's in that car.
However, billy's link clued me in that I mistook another blue RE car for this one. So this car below is apparently the one that ran the 56.094; not the one being discussed here. My mistake.
I'll admit I don't know a lot about buttonwillow, but I would challenge whether a stock gr86 could lap tsukuba in under 1min. Probably closer to 1:10 is more realistic. HKS's internal GR86 has a fastest lap of 55:978. You'll find it in position #66 on the link I provided above.
Given how short tsukuba is, I just want to reiterate that there really is a considerable difference in difficulty between running a 59:xx time and a 56:xx time.
As a reference point, here is a video of Tsuchiya driving a modified Porsche GT3 RS on slicks at tsukuba in 2022 and lapping a 59:278.
HKS did a 1:01.8 at Tsukuba in a stock GR86 modified with a muffler, tires and a small wing. A modest wing and a splitter could drop that time to sub-1.
A similar prepped car does about a 2:00 at Buttonwillow, while a GR86 with stock power and significant aero has done a 1:53 -so aero and tires alone made a 7 second difference at buttonwillow, which is ~ a 3.5 sec or so difference at Tsukuba; which would be well below 1-minute. I guess my point is that you don't need 500whp to turn fast lap times, and an FD with 400whp can be quite fast with good aero.
In Southern California, most track FDs have 350-400whp, and 500whp+ cars that i've seen tend to overheat very quickly and constantly have problems preventing them from turning continuous laps. Many of which do less than ideal things like mounting air filters behind the intercooler. Reliably tracking high horsepower FDs is significantly more difficult than drag racing or making that kind of power on the street. I'm looking forward to putting my build to the test tracking with 500whp+.
Yes your point about power at tsukuba is well made and I agree. That track certainly rewards down-force and momentum modifications. Hope I didn't come off as taking a position against the significance tires and aero can make; wasn't my intention and would be foolish. Simply illustrating that I find <1min at tsukuba to be fast/impressive and anything even less to not exactly be easy. This HKS GR86 you posted is a great example of cost/benefit and I think their 1:01.8 time with it is super impressive. There is a link to video coverage of the day in the thread you posted where you can see/learn some added details like that they also stripped out the interior to lighten up the car, installed an aftermarket LSD, added tuned coil overs, and put an endless brake setup on it as well. That thread also lists 1:08 as the true stock GR86 lap time so it seems HKS shaved 6.2sec off the factory stock time with those mods. Not earth shattering stuff in terms of car setup to be sure but more than a muffler, tires, and wing and to find their next 5.82 seconds at Tsukuba required this level of setup & investment LINK. You can actually see the progression of the car over time via that link which also shows that the car did not get under a minute before they turbocharged it. All very interesting and perhaps I'm simply easier to impress.
) last I saw.
