Created a monster!?
Discussion
:yikes:
Finally got round to stripping the injection system off the 390 today and fitting the one I've been working on for months.
First discovery was that NCK HAD ported the inlet manifold; not sure why I thought they hadn't but needless to say their efforts are better (and more severe) than mine :thumbup:
Now the engine's only done 10,000 miles since my rebuild so it wasn't entirely a surprise to see it still nice and shiny inside, though I was a bit miffed to see that the oil had a blackish tinge to it. I could have sworn it was only changed a couple of thousand miles back, I'll have to check.
Anyway, to business.
The 'new' injection system incorporates a mildly ported manifold, fatter injectors, shortened trumpets and a plenum/ trumpet insulator, with the trumpet base shortened to compensate. In effect this makes it the same port length as a standard setup, with short trumpets. Throttle body heater, cold start injector and thermotime switch have been deleted and blanked off.
I expected any improvement to show up at the top end, or at least upper midrange onwards, due to the shorter trumpets (the 'old' setup had full-length ones).
Wrong. :D
The throttle pot's set for 330 mV (just a lucky guess, I couldn't be bothered to knock it down 20mV for now). The airflow meter is a Jag one, with the spring tension reduced to get it somewhere near on the 'old' setup.
It started straight off, but the idle was up around 1500, With the screw all the way in it's still about 1000.
I set off and almost overshot the end of the road. It was instantly reminiscent of Patrick's SEAC at the BBWF :hehe: - slightest touch and you're in the scenery.
Once it warmed up I wound up the tension on the airflow meter and the snappy response dulled somewhat, but the idle is still too high.
That aside, it's a different car. The improved response is LOWER, not higher, in the rev range. Second gear around town is lunacy. I almost rear-ended about five cars just from the pickup.
Chist knows what the fuel economy is, but out on the open road it's a bit of an animal compared to before. It seems to run out of puff earlier than it did, I'm guessing due to AFM calibration still being wrong (mind you it could be the rev limiter playing silly bu99ers). Then again it could be the fuel pump failing to deliver!
As for the insulator, after a good thrash the plenum was merely warm. Then I touched the aux. air valve and almost lost the flesh off my finger! The temp gauge is reading about 15 degrees lower than before which I assume is down to the different temperature sender.
One thing is for sure: I need bigger brakes :D
Shame I have to put it away now and go to Ireland for three days.... :ranting:
Finally got round to stripping the injection system off the 390 today and fitting the one I've been working on for months.
First discovery was that NCK HAD ported the inlet manifold; not sure why I thought they hadn't but needless to say their efforts are better (and more severe) than mine :thumbup:
Now the engine's only done 10,000 miles since my rebuild so it wasn't entirely a surprise to see it still nice and shiny inside, though I was a bit miffed to see that the oil had a blackish tinge to it. I could have sworn it was only changed a couple of thousand miles back, I'll have to check.
Anyway, to business.
The 'new' injection system incorporates a mildly ported manifold, fatter injectors, shortened trumpets and a plenum/ trumpet insulator, with the trumpet base shortened to compensate. In effect this makes it the same port length as a standard setup, with short trumpets. Throttle body heater, cold start injector and thermotime switch have been deleted and blanked off.
I expected any improvement to show up at the top end, or at least upper midrange onwards, due to the shorter trumpets (the 'old' setup had full-length ones).
Wrong. :D
The throttle pot's set for 330 mV (just a lucky guess, I couldn't be bothered to knock it down 20mV for now). The airflow meter is a Jag one, with the spring tension reduced to get it somewhere near on the 'old' setup.
It started straight off, but the idle was up around 1500, With the screw all the way in it's still about 1000.
I set off and almost overshot the end of the road. It was instantly reminiscent of Patrick's SEAC at the BBWF :hehe: - slightest touch and you're in the scenery.
Once it warmed up I wound up the tension on the airflow meter and the snappy response dulled somewhat, but the idle is still too high.
That aside, it's a different car. The improved response is LOWER, not higher, in the rev range. Second gear around town is lunacy. I almost rear-ended about five cars just from the pickup.
Chist knows what the fuel economy is, but out on the open road it's a bit of an animal compared to before. It seems to run out of puff earlier than it did, I'm guessing due to AFM calibration still being wrong (mind you it could be the rev limiter playing silly bu99ers). Then again it could be the fuel pump failing to deliver!
As for the insulator, after a good thrash the plenum was merely warm. Then I touched the aux. air valve and almost lost the flesh off my finger! The temp gauge is reading about 15 degrees lower than before which I assume is down to the different temperature sender.
One thing is for sure: I need bigger brakes :D
Shame I have to put it away now and go to Ireland for three days.... :ranting:
Right, now that Fotangrot is behaving itself, some piccies...
I think I remember how it works...
Groovy new injectors, baby:-
Taking shape, but spot the deliberate mistake that would waste time later:-
... and the finished article on the car:-
...looks nicer than crusty bare alloy, even with the bald patch where I rubbed the paint off
Edit: hmm, that coolant header looks a bit naff. Time for an alloy one?
>> Edited by wedg1e on Tuesday 27th September 01:21
I think I remember how it works...
Groovy new injectors, baby:-
Taking shape, but spot the deliberate mistake that would waste time later:-
... and the finished article on the car:-
...looks nicer than crusty bare alloy, even with the bald patch where I rubbed the paint off
Edit: hmm, that coolant header looks a bit naff. Time for an alloy one?
>> Edited by wedg1e on Tuesday 27th September 01:21
tallbloke said:
The kind that'll rub off when he shuts the bonnet and goes for a drive.
I'm working on a little something, well gathering bits around me to throw into a cauldron, that might help matters here. It's for the Chim racer, but could transfer across to any RV8 engine bay where height is restrictive. I'll keep you posted
Regards
Iain
Hmmm. The paint is sold as 'metallic black' but looks more like graphite grey to me...
Rubs off fairly easily until it's seen some heat, then it seems quite robust (sorry Rog
)
I took a lot of casting marks off the various parts, looks a lot nicer as a result. Also machined a flat area at the top front of the plenum for a suitable badge... pantograph engraver anyone?
Graham: your pipe may not be blue but I bet it's still quicker...
Rubs off fairly easily until it's seen some heat, then it seems quite robust (sorry Rog
) I took a lot of casting marks off the various parts, looks a lot nicer as a result. Also machined a flat area at the top front of the plenum for a suitable badge... pantograph engraver anyone?
Graham: your pipe may not be blue but I bet it's still quicker...
Wedg1e, being a bit anal about things...
Is it possible to use non-metallic bolts to act as the ultimate insulator between the the manifold and the trumpets, in order to totally insulate things? I'm guessing standard glass filled Nylon6 bolts wouldnt have the strength, any other options? Would something like PEEK do the job?
Or a sleeved stud?
Regards
Iain
Is it possible to use non-metallic bolts to act as the ultimate insulator between the the manifold and the trumpets, in order to totally insulate things? I'm guessing standard glass filled Nylon6 bolts wouldnt have the strength, any other options? Would something like PEEK do the job?
Or a sleeved stud?
Regards
Iain
You need to get out more, mate
I can see where you're coming from but I don't think this is the ultimate fix for more power, just a cheap and cheerful mod.
What you do find is that the top end stays cool while you're running, but once the car has stood for a while heat soak (perhaps including radiated heat from the rocker covers?) does eventually raise the plenum temperature quite high - not as much as usual, though.
I was contemplating dividing off the l/h side of the engine bay and moving the AFM to where the header tank is now, then the air filter could draw from a reservoir of relatively cool air fed by the vent on the front l/h of the bonnet. Of course this would mean a new header tank where the AFM/ filter are now, but it works for Steve Evans...
I can see where you're coming from but I don't think this is the ultimate fix for more power, just a cheap and cheerful mod.
What you do find is that the top end stays cool while you're running, but once the car has stood for a while heat soak (perhaps including radiated heat from the rocker covers?) does eventually raise the plenum temperature quite high - not as much as usual, though.
I was contemplating dividing off the l/h side of the engine bay and moving the AFM to where the header tank is now, then the air filter could draw from a reservoir of relatively cool air fed by the vent on the front l/h of the bonnet. Of course this would mean a new header tank where the AFM/ filter are now, but it works for Steve Evans...
wedg1e said:
I was contemplating dividing off the l/h side of the engine bay and moving the AFM to where the header tank is now, then the air filter could draw from a reservoir of relatively cool air fed by the vent on the front l/h of the bonnet. Of course this would mean a new header tank where the AFM/ filter are now, but it works for Steve Evans...
Have done something along these lines myself but a bit more radical - made a huge difference to inlet temps.
Used a Range Rover coolant tank and mounted it on the bulkhead dead central as high as I could - no coolant airlock problems since either, I guess because coolant level is now higher than any pipework !
Have a large insulated box now where the coolant header used to be with the AFM and filter in it with a ram pipe feeding it ambient air. Used to need both fans on when going less than 70km/hr on a 40 degree day and after the mod they only cut in when stationary and it hasn't pinked since either.
For extra 
brownie points I think an insulating washer under the bolt heads would reduce the conduction significantly. Heat transfer across a clamped joint goes up with clamping force (pressure times area), and the total force on these bolts is the same as the clamping load on the trumpet base.
brownie points I think an insulating washer under the bolt heads would reduce the conduction significantly. Heat transfer across a clamped joint goes up with clamping force (pressure times area), and the total force on these bolts is the same as the clamping load on the trumpet base. wedg1e said:
I was contemplating dividing off the l/h side of the engine bay and moving the AFM to where the header tank is now, then the air filter could draw from a reservoir of relatively cool air fed by the vent on the front l/h of the bonnet. Of course this would mean a new header tank where the AFM/ filter are now, but it works for Steve Evans...
This was recomended too me by Mark Adams when i was down at Austec with mine, coupled with the 390 bonnet which has the vents to allow cool air in in that area.
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