Jump to content
SAU Community

M35 Bonnet Lift - Heat Extraction

Equilibrise

By Equilibrise,
in Four Door Family & Wagoneers

 Share

Recommended Posts

DMM Apprentice

DMM

Posted
Posted

Good idea!

What is actually happening is air is being forced in :P

The M35s have the zero lift aero design which actually generates some reasonable vacuum under the car. Right at the base of the windscreen is a high pressure buffer area, which would force cleaner air into the engine bay. These two working in combination would be helping to draw some fresher air into the engine bay!

Good work!!

DMM Apprentice

DMM

Posted
Posted

Maybe. Or the air being forced the back in makes it harder for air to go through the radiator.

Fortunately not, the combined frontal positive pressure and combined undertray negative pressure is combined greater than the high pressure at the base of the windscreen. It will only stunt radiator flow a little bit, nothing worth worry about.

Ben C34 Grand Master

Ben C34

Posted
Posted

Fortunately not, the combined frontal positive pressure and combined undertray negative pressure is combined greater than the high pressure at the base of the windscreen. It will only stunt radiator flow a little bit, nothing worth worry about.

Maybe.

My only issue is that you are guessing.

Ben C34 Grand Master

Ben C34

Posted
Posted

I don't need data to call you out for guessing though do I?

Here's a question for you .

How much cooling affect does an engine get from air generally blowing over it vs the actual radiator?

I don't know. But I would have a guess ;) and say the air though the radiator is way more important.

DMM Apprentice

DMM

Posted
Posted

I think maybe you misinterpreted my first post. Not trying to be argumentative here either.

I like his idea, I personally think it would work well as its removing heat from a critical area of the engine bay that sees very large amounts of heat saturation. This would have small benefits to hoses and component life in that area, as well as manifold heat soak would be brought down a little.

The reason it would work well in my opinion as its effects would only become valutive at higher road speeds when a reasonable pressure system can build at the windscreen base. At the time these speeds are achieved the radiator system at the front of the car is already achieving the maximum transfer of heat from air speeds. The only way the radiator system could become more efficient at this point is if the ambient air temperature was to become lower.

Dan_J Veteran

Dan_J

Posted
Posted

Thanks Dale. That is a pretty good temp compared to mine. I don't have a nismo thermostat as yet. I have got a 53mm aluminium radiator, except when i installed it i didnt trim enough of the shroud off so when driving it for the first time after the install, when i came off boost the engine lurched forward and plowed the clutch fan into the shroud and thus destroyed both...so i installed twin thermos in a sealed shroud i made up. So until i can get my hands on a decently priced shroud and clutch fan i have to live with the davies craig setup.

On another note: i put the undertray back on today for the first time since i bought the car. Water temp is between 90-93, so 1 deg higher on the lower running temp;same on the higher end. Intake temps were lower!!! I think this is due to more air being channeled into the cold air intake (ducting next to the I/C).

pics of shroud and how the thermos are mounted ?

there is a wrong way of mounting thermos which will block air flow

Equilibrise Community Regular

Equilibrise

Posted
  • Author
Posted

Thanks for the input guys.

I have had the bonnet like this for a little while now and although it is drawing air in at the lifted point I am not experiencing any temperature rise in any driving situation. I am in fact experiencing a temperature loss and improved drivability. I am not recommending anyone else to or not to do this, I am merely posting my experiences, and as dale said earlier, it is just another version of whats been done before.

I am yet to get my hands on the appropriate equipment to monitor the pressures, but when i do i will post up the data.

To add to DMMs discusion points, before i lifted the bonnet i could not keep my hand on intake manifold at all. Now, after a spirited drive i can keep my hand on it as long as i want - still feels warm, but not nearly as scolding as before. So i'm guessing that the heat from the exhaust manifold that wraps around the back of the motor is being extracted rather than heating up the intake.

I'll take a pic of the shroud in the daylight, but i am still convinced that the clutch fan is a better option.

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • JC71
      new 1.5 LSD issues/concerns

      By JC71 · Posted

      sold listed as a Tomei LSD 1.5 Way For 1998+ Nissan Skyline ER34 25GT RB25DE w/Open R200 https://www.ebay.com/itm/174006114594?campid=5338967980&mkevt=1&mkcid=1&toolid=10050&customid=&mkrid=711-53200-19255-0&loc_physical_ms=108689&loc_interest_ms=&campid=5338967980&mkevt=1&mkcid=1&toolid=10050&customid=71883f2ccc571356e0a757bc7adfdde2&mkrid=710-53481-19255-0&loc_physical_ms=108689&loc_interest_ms= it went in like butter all gears, alignment, back lash etc, rotation and clearances correct, and if rolling all rotates smooth and free when coasting down road , clutch in or out over 10 mph smooth... its the binding, clunking and jerking from a stop that is most concerning, also seems like its going to tear the tires off in 10 miles of normal road driving. 
    • Kinkstaah
      new 1.5 LSD issues/concerns

      By Kinkstaah · Posted

      What 1.5 way? There's no such thing really as a 1.5 way, just different ways of explaining 2 ways with different ramp rates. HOWEVER. In any driving in a straight line your 1.5 or 2 or 1.7 way should have no clunking at all. With the clutch fully depressed the diff should be silent (unless it's welded but I'm assuming it's not). Something aint right here.
    • JC71
      new 1.5 LSD issues/concerns

      By JC71 · Posted

      Clutch is a spec brand, new clutch system,( PP, flywheel, friction disc, etc. pull type) installed 100 miles ago, with no problems.
    • JC71
      new 1.5 LSD issues/concerns

      By JC71 · Posted

      looking for some help and maybe some insight on others experience with a new LSD. R34 GT ran and drove beautifully, but always alot of grip loss due to the open R200 rear end, so I just installed a new 1.5 LSD way into the stock open R200 for a ER34. Simple. Everything seemed right. I test drove for the first time this weekend. as I started to back out the garage the first time slowly with tires straight it sounded and felt like I had a loose or half disconnected drive shaft...that was clucking around loose and shaking entire vehicle, and making it feel like the trans clutch was spontaneously slipping then grabbing very roughly while just letting out pedal slowly. I backed it out went to pull forward with the same noise, shake and slip grab feeling with hesitation, I turned the tires to back out more and then pulled ahead some same thing but worst because of added wheel resistance (which that I expected) puzzled … pulling it back in checking everything over and finding nothing wrong, I tried it the next day. same thing, couldn’t believe how it shook everything again making a terrible noise and making it feel like the trans clutch was slipping and grabbing, but I got it out of garage into the driveway, got it straight, drove forward and then reveres a few times in a straight line everything shaking , causing what felt like clutch slip and grab every time, sounded like right behind front driver tire and I could feel it in the floor board with my feet,... worst right when beginning to let clutch pedal out to engage slightly, shuttering and sounding terrible along the way…I managed to slowly get down the road, babying it the whole way, once I was rolling (out of 1st) seemed to be better and between shifts, then clutch felt closer to normal…not slip/ grab etc., but back down to any stop, straight road or turning, same thing. Made no difference if all tires were straight or if I was turning. All other gauge read out correct. with in 2 miles as planned I reached the empty parking lot and performed the break in procedure that came with lsd, essentially to drive in a figure 8 a bunch.  Did this, binding chattering, and shaking the car the whole way. I drove it back home seemed somewhat normal once I was in straight line and past 10 mph or so, and I know it will “bind” on corners and cause some tires squeal when turning especially from a stop, but when I begin to move it still causes what feels like the trans clutch to slip and jerk badly as well as shaking the entire car, and sounds terrible, that I didn’t expect. I used the fluid they supplied with LSD kit and did the breaking, planning to change fluid as they suggest after breaking, but wondering will it get smoother or less aggressive with use? maybe a 1.5 is just too aggressive for normal road driving?   I have a LSD that I put in my 71 cuda when I restored it, with amazing smooth , quite yet effective results. Different style LSD but that ones a joy to drive. maybe expecting too much from this R200?
    • Matt Z
      SAU NSW - Archies Flame Grille Meet & Cruise to Kurnell

      By Matt Z · Posted

      Join SAU NSW for a flame-grilled feed & flame-spitting cruise! Sunday 17th August 2025 3:30PM Meeting Archies Flame Grille Sylvania Waters 4:45PM Cruise Departure 5:15PM Arrival at Cape Solander Kurnell Meet Location: Archies Flame Grille Final Destination: Cape Solander Kurnell *Disclaimer* There will be a lead and follow car so no one should get lost. If you would like to attend or bring others along please put your name down and a +1 as numbers will be needed prior! This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAU:NSW event and will be run under a CAMS permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU NSW and thus, treat others accordingly. • Any misbehavior will not be tolerated and you will be asked to leave.
×
×
  • Create New...