Ram air induction on a mk2 with a di

[Retrohowla]

Can anyone advise if this has been done, will/wont work, wreck my engine etc?
I have a friend who made a ram air scoop for his seriously slow astra diesel, he seems to rate it and says it makes the world of difference trying to overtake over about 40mph.
I was thinking it might be a good improvement to the mk2, shes running a 2.5 di (92) and although not slow for a di it does stuggle on the motorway hills etc.

Will forcing air into the motor blow it up? (bear in mind this motor has done 215k and never been apart to my knowledge)

Any thoughts, have i gone mad?

[Luke]

i'd be suprised if you'd notice

cant see it doing any harm providing you still keep the air filter

[bazw]

on a car there is a 1.5 X air pressure zone below the windscreen if its an older 2/3 box car style body's (cortina, granny , astra ) this is why the air vent is mounted there

anything after a mk2 tranny does not get the higher pressure there as the bonnet to windscreen interface ( big word for the day ) is not such a big angle to build pressure

to get a boost from it you would need to have a huge scoop feeding into an engine with no leakage and be at speed you must also build in a baffle system to separate rain out of the air and drain away when moving and at a stand still
this is why a pontiac firebird and trans am (Smokey and the bandit black car for burt renolds) with ram induction have the scoop facing backwards , highest air pressure and does not get water in

hth

[MrMPuk]

All induction kits do on the Di is make the even noiser!

[Retrohowla]

The proto my friend built was using a scoop mounted below the rad facing directly forward to intercept air flowing below the car, this was ducted to a seperating tank before the airbox to combat the rain/water issues, it had a drain scew to empty any water build up after a prolonged journey in wet conditions.

The scoop itself was about 150mm high by about 350mm wide and funneled down to approx 60mm id induction tube.
Like i say he seemed to rate it with no other mods to the engine or induction system other than keeping an air filter in the form of a conical filter mounted inside of the seperating tank

I just wondered if it had been done before with a di and if it would be harmfull to the engine at all and if it would make a difference?

[bazw]

have a read of this
http://www.autospeed.co.nz/cms/article.html?&A=0629

it can give you ideas for more air to the engine than most mods and cheap

where he has his scoop is another high air pressure zone

[Retrohowla]

thanks for the link, its pretty indepth mind i will be trolling through that to pick up some pointers but so far i can see the benefits i could gain just by taking the air from a high pressure zone so thanks!
You never know, it might be worth a try

[baconsdozen]

The power an engine produses depends on the weight of air and fuel it is burning.You will get a slight power increase by funneling in air from outside the underbonnet area (at the expense of smooth running when the engine is cold) as it will be clean air at a lower temperature.There is no such thing as a free lunch though,to create any sort of pressure to ram air in would need a huge scoop and high speeds.The was a paper published some years back calculating the power gain against the extra air resistance a large scoop generated,the conclusion was that other than ensuring the inlet to the intake system operated in a turbulence free zone and drew in air that hadn't been heated under the bonnet there was no real point in outside scoops.

[bazw]

thanks for the link, its pretty indepth mind i will be trolling through that to pick up some pointers but so far i can see the benefits i could gain just by taking the air from a high pressure zone so thanks!
You never know, it might be worth a try

it mostly boils down to making the flow smooth

things like the ribbed flexie hoses being changed to smooth pipes and just a small flexie joint ,or the way air boxes are baffled and where you take your air inlet from

things like on my old sierra 2L injection the air inlet came from a flexie feed from the side of the inner wing so it had dusty or damp air depending on the weather so i made a duct from a square to round drain adapter and fed the air filter from a spot light blank in the front bumper ( ford later changed to a plastic duct feeding from behind the bumper ) this was worth 2 whole bhp on a rolling road ( checked when i had an emerald injection system fitted )

i would agree about the drag from a scoop (+ most home made and some pro made are hideous ) but air taken from a grill or in / under the bumper and with provision for draining as it goes can be good

i think jags used to take air from a grill above the head lights to feed the vent system in some of the saloons

[Retrohowla]

Yeah i wont be sticking some huge plastic scoop to my bonnet like some boy racer thats for sure! I just thought if i could pick up clean cold air from under the van and funnel it into the intake it might give the old girl a little more chance of holding its speed when i hit a hill?
Well thanks for all your comments/views there does seem to be links to power increase and clean/high pressure air but i doubt it will make a difference on an ageing 2.5di, worth a thought if nothing else mind

[redeemer]

So what about fitting a small turbo to the di? My friend suggested me fitting a turbo to my 86' 2.5di. He told me to find an oil main from the oil pump (idealy that pipe going in the vacuum pump behind the alternator) to supply oil for the turbo, and cut the silencer and do some modifications and remove the di air filter and then fit a cone filter to the turbo inlet. Would it damage the engine or not ? He told me since the engine crank shaft is mounted on four bearing not three (like the BMC engines) it would be safe. What do you suggest me?

[bazw]

So what about fitting a small turbo to the di? My friend suggested me fitting a turbo to my 86' 2.5di. He told me to find an oil main from the oil pump (idealy that pipe going in the vacuum pump behind the alternator) to supply oil for the turbo, and cut the silencer and do some modifications and remove the di air filter and then fit a cone filter to the turbo inlet. Would it damage the engine or not ? He told me since the engine crank shaft is mounted on four bearing not three (like the BMC engines) it would be safe. What do you suggest me?

i think its 5 bearings as an even piston engine has to have an odd number of bearings (front, back and 1 or 3 in between)

i would just go get the stuff from a tranny if you want a turbo and fit the full set up , why make it hard on yourself