thegreatestben

Romans COD piece

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On 01/09/2013 at 18:12, Roman said:

No disputing that looks ultra sweet.

 

However driveway at my new house makes any slammage impossible, need planks of wood to get it up the drive as is.

After this is certed I'm not planning to do anything further to it, apart from tending to maintenance and breakages.

Lies!!!

just bought a carina coupe myself, been through your whole build thread, and now making my way through the discussion thread hoping to take in some of your test and tries.  I think I was dreaming about graphs last night!!!

1 major question which will help heaps with the start of my setup (planning similar to you, fun track/weekend car, probable gen 3 3SGE swap to come), what spring rates did you end up running front and rear?

love your work, been following this build since the start and it looks like so much fun

 

cheers

Matt

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Thanks Matt, I am currently using 5kg front and 3.5kg rear.

This is a reasonably nice balance but with a touch of understeer so I might add the rear swaybar on now. 

Or otherwise get some new rear springs made in 4kg or 4.5kg.

 

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Awesome, cheers. That should give me a starting point at least.

 

just curious on your thoughts on the power loss with quads. You think the reduced airflow (from cross section of ITB throats compared to a large single) is a major factor, or underbonnet intake temp would be a big problem as well?

 

I'm leaning towards a 3SGE swap with either twin carbs to start, then some form of quad throttle bodies later, but I have to admit that your cross section comparison has got me thinking. I've got a spare bonnet so I could cut it up to promote cold air being directly fed to the intake, but if it's only part of the problem then I may have to change my plans

 

cheers

Matt

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Air through the bonnet isnt necessarily a good plan, if you look at my aerodynamic cross section of the carina there is actually lower pressure and not so much airflow there. 

Take a look at @Truenotch's AE86 project, he has quad throttles on a beams engine with what I consider to be the ideal intake setup. (Apart from no filter haha)

After talking to the very talented Mr Robbie Whitley, he has suggested one of the primary reason for quad throttles is that when you start using a very aggressive cam.
With a single throttle at part throttle the vaccum in the plenum pulls the air and fuel back out of the cylinder and exhaust gas back through. Which means your motor runs like a sack of shit. But having quad throttles means that the vaccum is lower, and also there is only so much area behind the throttle plate to blow back into so the problem is reduced. 

Another big benefit of quad throttles is being able to easily change the length of your runners which can push your powerband around a bit... Very hard to do this with a plenum.

Also, just re: under bonnet temperatures... The High Performance Academy 350Z gains ~15kw if you tilt the intake pipe up so its getting colder air instead of air behind the radiator. Can make a big difference! 

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Your revs are too far from the sweet spot.

bqyjbw4a.y3u.jpg

 

Interesting re outer injectors.   im still on the fence, if I should try  the outboard setup on mine

 

 

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Yeah well its been proven to work by others, its also possible that it just wasnt fuelling evenly between cylinders on mine as the runners arent exactly the same. 

But either way, in my case the benefits werent worth the downsides. 

Also if you have a quad throttle setup where it's at the same temperature as the head then you'll probably have a better result as the fuel evaporates a lot quicker.

Something interesting, I saw someone post a factory inlet manifold for an SR16VE N1 and it has staged injection from factory. The other 4 injectors are in the head.

$_1.JPG

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Alsooooooooooooooooooo

I wired in an exhaust pressure sensor, and wtf'd at the results hahaha. 

When there's more air flowing through the pipe, the pressure goes down:

 

I reckon you need encouragement for more graphs, so... what's the cam timing doing when the pressure goes down?

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The cam timing advances through the midrange, and pulls back towards top rpm. 

There isnt really a pressure trend that follows this, or at least it's not evident from the resolution available with this sensor. 

With a 1 bar absolute map sensor or using a differential pressure sensor this might be more evident though.

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I'm no expert  on exhausts but I am surprised that the sensor's max reading is 1 ATM. What sort of sensor is it? Total pressure or static? 

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Trust me I'm surprised as well.

I've confirmed that the sensor reads higher pressure fine, and when the engine is off the signal is the same as barometric pressure. 

I can only think that either the diameter of the line is too tiny for it to work effectively, or, there's a venturi type thing happening even at idle. 

But its definitely weird. Might try again with a bigger diameter line for starters.

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where in the exhaust is the sensor plumbed in?     does the signal  jump around if you watch it in real time?

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On 11/25/2017 at 09:34, kpr said:

where in the exhaust is the sensor plumbed in?     does the signal  jump around if you watch it in real time?

Plumbed in near the end of the 2-1 section, as this is where the standard narrowband sensor was positioned. 

I really just think the issue here might have been that the lines were too small and the pressure scale of the sensor too high.

For the moment I've retired it, but will give it a rethink later on. Having the MAF back in is proving interesting enough so far.

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Are you using vacuum  (or pressure assisted) infusion with your CF bits? They're looking a bit dry.

 

Also, could I convince you of the wonder that is glass fiber? Significantly cheaper than CF and you'll get the majority of the weight savings with it, unless you really optimize the structure to its limits (which costs more $$ and time than you'd ever save). Fiberglass is also an electrical insulator, whereas CF will end badly if you mix it with electricity. /I'm a bit of a glass barry.

 

But yeah, fiberglass doesn't have the same cool factor as carbon..

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other weight saving ideas - 

Underseal/sound deadening, hood lining, fibreglass mould the dash and throw the old one away, do you really need all those wires?

Speed holes!!!

but seriously, good thinking mate be interesting to see results

I remember a test many years ago where they took an old 120y or something and sent it down a drag strip, then slowly started taking shit off it until the absolute bare minimum required to get to the other end was left on it (basically a shell with a motor) and they shaved off a few seconds

 

 

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1 hour ago, ajg193 said:

Are you using vacuum  (or pressure assisted) infusion with your CF bits? They're looking a bit dry.

 

Also, could I convince you of the wonder that is glass fiber? Significantly cheaper than CF and you'll get the majority of the weight savings with it, unless you really optimize the structure to its limits (which costs more $$ and time than you'd ever save). Fiberglass is also an electrical insulator, whereas CF will end badly if you mix it with electricity. /I'm a bit of a glass barry.

 

But yeah, fiberglass doesn't have the same cool factor as carbon..

To be honest Carbon Fibre material itself is neither here nor there, as its the expoxy and time making molds that is the true "cost" of the process.
 

I was not expecting the dry appearance either, I think it's because I had a shitload of wax on the mold as I was expecting it all to permanently sandwich together and be a disaster.
But I can assure you that each layer got an exceptionally liberal application of epoxy as I did a wet layup like you'd do with fibreglass
(partially because I mixed hilariously way too much) and as best I can tell there are no issues with layer adhesion on this test piece at least. Heaps of the epoxy squished out the sides. I wasnt even clamping the mold together particularly well, I just put it under the leg of my table haha. For the next thing I'll try, I'll use massively less wax and see how it goes as I think that will affect the outer coating a fair bit.

Yes, Carbon does indeed conduct electricity but so does the steel that my entire car is made from. My process will work for fibreglass as well though, so whatever's best tool for the job.
I have been reading about how it can cause galvanic corrosion with aluminium though so I guess I'll need to be mindful of that.

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1 hour ago, dabuzz said:

other weight saving ideas - 

Underseal/sound deadening, hood lining, fibreglass mould the dash and throw the old one away, do you really need all those wires?

Speed holes!!!

but seriously, good thinking mate be interesting to see results

I remember a test many years ago where they took an old 120y or something and sent it down a drag strip, then slowly started taking shit off it until the absolute bare minimum required to get to the other end was left on it (basically a shell with a motor) and they shaved off a few seconds

 

 

Haha yeah this article? Cracked me up, so good 

http://www.rcramer.com/fun/econobox/

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A lot of the EFI wizardry sails straight over my head as I've never played around with this stuff but man your updates are interesting, really looking forward to seeing what you do next!

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Quote

So will get some lighter ones, maybe with fixed rails if I ditch the rear seats.

My understanding was for WOF's you need adjustable seat rails (locking on both sides if used on track under motorsport regs) authority card however allows you to run fixed... Might want to double check the regs.

Could also drop your rim size down to save a bit of weight from the rim/tyre combo. Factory front calipers on cars are also normally pretty heavy, so going with an aftermarket brand could save you a couple of kg's each side (if you haven't already). Obviously all $$$, plus changes to cert plate which is a pain.

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