Jump to content
SAU Community

Recommended Posts

Put a gurney flap on it Russ......

that's what I was getting at. without gurney flap it's not doing nearly as much as it could be. especially with a very flat shape like that. it will be low drag which is good, but low downforce too which is not.

yeah a big part of the downforce comes from that little 20mm flap on the top. it's been tested many times. most of the jap wings (the real ones that work) come without gurney flap for street cars who just want the look without all the drag and with gurney flap for track cars. yes it is adjustable but past a certain angle it will not make any more downforce and the wing will stall. hence you need the flap. if you can't buy one for the wing they are easy to make/have made.

What Baron has already said Russ, it's very important, and honestly, without it, it's an oranment.

A small 20mm gurney will massively increase the downforce, and really, creates bugger all drag, because all is it doing is creating a high pressure zone on the top 20 to 40mm of the wing's surface, pushing it down.

Without it, all you have is a blade running through the air, and when you increase the angle of attack, you are creating as much horizontal drag as you are downforce. Very inefficient.

What Baron has already said Russ, it's very important, and honestly, without it, it's an oranment.

A small 20mm gurney will massively increase the downforce, and really, creates bugger all drag, because all is it doing is creating a high pressure zone on the top 20 to 40mm of the wing's surface, pushing it down.

Without it, all you have is a blade running through the air, and when you increase the angle of attack, you are creating as much horizontal drag as you are downforce. Very inefficient.

That is fine but how much rear downforce do you really want/need. No point having it if you cannot match it to the front downforce which is always the more difficult of the two to generate.

Sure, but it's not difficult to match that downforce with a 4 inch splitter on the front, which is simply creating a high pressure zone in front of the front bar. I assume Russ is adding a splitter given it is so easy, (along with a decent undertray to minimise front lift).

The rear wing is typically actually only going some way toward negating the lift generated by a sedan shaped car (low pressure area around the base of rear screen).

That's my take on it anyway, and of course I'm not an aerodynamicist, but I read a lot. :P

Edited by Marlin

yeah me too being an amateur aerodynamicist. I have read a lot and have a fair bit of practical experience with sedans and some open wheelers too (which are a piece of piss compared to the bunky cars we have).

yeah big aerofoil wing is fine but as marlin said big trade off in drag v downforce and they can only generate so much before the angle of the wing goes too far and it's in stall. gurney flap adds heaps. as far as the front goes you want an undertray to reduce lift (even better if you can incorporate an upside down type wing shape into it which creates a negative pressure zone - downforce), splitter which helps guide the air where you want it (up and over the car), even front anti-dive plates/carnards help create front downforce and grip.

too much rear downforce can be a bad thing in that you end up with high speed understeer (not nice!) but it's pretty easily tunable and to be honest most of our tracks are not fast enough for most to notice anything other than a really bad downforce imbalance. the small imbalances between front and rear downforce don't seem to cause too much grief, but you only need to look at cars with good rear wings through turn 1 at eastern creek to know if they are working or not. same goes for the front aero. lots of time to be gained through T1 at EC with more aero at both ends.

anyway, the main point is for a wing on a circuit car the gurney flap is an important tuning tool. should definitely run one or at least try one.

Thanks for the input guys. I honestly didn't consider it. They guy making this wing for me has mostly made drag wings and is only making what I'm asking him to make.

It has a big surface area and I expect a big increase in downforce compared to what I've had. The front splitter/undertray I am fitting also isn't huge. It's a start and I could easily get this guy to make up the gurney flap and a bigger undertray when I have a better idea of what I want.

It's all testing to me as I have had little exposure to the big dollar stuff you guys have seen. Feel free to invite me into your pits at superlap *wink-wink* Ben :)

I've got a 25 with 26 internals with a 6 Boost and 44 tial, i dont have any creep issues, runs really well now.

On another point, did you think about keeping the stock inlet manifold????

the reason i say this is on my newest engine, we used a Greddy plenum, tomei cams and 26 internals, when it was tuned the engine was extremely lazy, didnt come on full power till around 5k, after much deliberation we decided to put the stock manifold back on, now the car has picked up around a 1000rpm of useful power and it hasn't even been retuned yet.

I dont mean to hijack your build thread, just curious.

See how the gate pipe is at 90deg to the flow of the exhaust gases. That's what was causing all our issues with 6boost manifolds... should reweld the pipe to angle with the direction of flow, like the photo roy posted a while ago

This was considered but couldn't be done without redoing the whole manifold. Tuning tomorrow. See how we go...

I've got a 25 with 26 internals with a 6 Boost and 44 tial, i dont have any creep issues, runs really well now.

On another point, did you think about keeping the stock inlet manifold????

the reason i say this is on my newest engine, we used a Greddy plenum, tomei cams and 26 internals, when it was tuned the engine was extremely lazy, didnt come on full power till around 5k, after much deliberation we decided to put the stock manifold back on, now the car has picked up around a 1000rpm of useful power and it hasn't even been retuned yet.

I dont mean to hijack your build thread, just curious.

Yeah Roy is a big fan of standard manifold. Good for torque and mid range response. From what we saw when it was on the dyno this comes on really early anyway. We'll see tomorrow.

New 10mm slip on spacers are a perfect fit on the front. They were custom made for us locally. Also have Nismo long wheel studs installed.

These were needed for inner clearance for the front. Now effectively 10.5 +5 lol

post-10715-0-57127400-1308579080_thumb.jpg

Custom tailshaft loop made to accomodate the big exhaust and way stronger than the standard one.

post-10715-0-80576000-1308579194_thumb.jpg

This was considered but couldn't be done without redoing the whole manifold. Tuning tomorrow. See how we go...

Ah fair enough, that is a bit of a bugger! Hopefully all goes well then... My GTR did have a 6boost and 90 degree pipe and I had issues holding less than 18psi, fingers crossed all goes well today :cheers:

Yeah Roy is a big fan of standard manifold. Good for torque and mid range response. From what we saw when it was on the dyno this comes on really early anyway. We'll see tomorrow.

fair enough, will be interested to see how you go. Looks like it'll be a good thing when its done.

Good work

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
    • Yea - I mean I've seen my fuel pump which is decades old and uh, while I'm not saying this with real knowledge... but I sure get the ick at using anything in the fuel system that produced the state of that pump. Many years ago I went through multiple pumps (and strainers) before I dropped the tank to clean it out with extreme violence. I'm talking the car would do maybe 50km before coming to a halt, which resulted in me cleaning out the filter with some brake cleaner and going on my way. None of my stuff ever looked like what came out of your fuel tank. I don't think I'd be happy with it unless every single component was replaced (or at least checked/cleaned/confirmed to be clean here).
    • I'm not going to recommend an EBC pad. I don't like them. Just about anything else would suit me better. I've been using Intima pads for a while now.
×
×
  • Create New...