Technical 34mm ITB's in the post :)

[randomizered]

I'll post pics when they arrive, and the job customising and fitting them to the car.

They may be rubbish, and a waste of time, but it's something I've been looking at doing for ages, and now it's not the dailey driver, I can fiddle a little more

Should sound nice if nothing else.

I'm hoping I don't loose too much low down torque, but thats why I went so small. On the 16v it's all about reving it anyway :slayer:

Kristian

 

[Todger182]

Hehe nice, when can I have a proper gander at your car? (instead of watching it go past me )

Thanks

 

[randomizered]

It's off the road at the minute. I'm:

rewiring
refitting the interior
sorting the arches
fitting the body kit
messing with the ITB's

etc.

In a month or two it will be runing again, and you can have a gander

 

[Todger182]

YAY!!! at that point I will hopefully have the 1.4 16v engine sittin in my shed half stripped, or maybe half re-built.

Thanks

 

[Whiley]

aggressive cams + higher rpm aswell i hopes

 

[Brooky]

im waiting on some silicone hoses then i can crack on and make my manifold for mine

 

[arc]

speaking of higher RPMs being where the power is, Kris - does your engine struggle for breath at all at higher (6k+) RPM? Mine seems to wimp out a bit, finally took it for a good 200mile blast up the motorway. it is running 1242 16v stock TB mind. Just wondering if it's running out of air, or the ignition isn't advanced enough at the top end.

 

[fingers99]

And the redline on the 1.4 16v engine is?

 

[craigb244]

you going to get some very spicy cams?

 

[randomizered]

speaking of higher RPMs being where the power is, Kris - does your engine struggle for breath at all at higher (6k+) RPM? Mine seems to wimp out a bit, finally took it for a good 200mile blast up the motorway. it is running 1242 16v stock TB mind. Just wondering if it's running out of air, or the ignition isn't advanced enough at the top end.

I dont' run much advance, and it's strong all the way up. Maybe thats the large trhottle body (48mm) and the larger plastic intake. I also use some very high flow injectors as well.

And the redline on the 1.4 16v engine is?

7200 rpm

you going to get some very spicy cams?

Nah, the rpm limit will stay at 7200, the cams are reprofiled anyway, and i'm not looking to spend much at the moment.

I imagine I can get this mod done all in for £100ish. If it runs like crap, so what, it'll have been fun messing

 

[fingers99]

Piston speeds for 84mm stroke (1.4 SuperFIRE)

6,000rpm = 3307.087fps
6,250rpm = 3444.882fps
6,500rpm = 3582.677fps
6,750rpm = 3720.472fps
7,000rpm = 3858.268fps
7,250rpm = 3996.063fps
7,500rpm = 4133.858fps
7,750rpm = 4271.654fps
8,000rpm = 4409.449fps



4750fps = F1?

Generally -- depending on who you talk to -- 3,500 or 4,000 are regarded as upper limits. In full race trim (and with full race rebuild schedules) it seems the 2 litre twin cams can be run at 7,250 for brief periods, but that's with forged pistons, one peice valves, bronze valve guides, peened rods, special bearings and a re-worked crank.

Scary stuff. Seems that the Poles can get 140bhp out of them with reasonable (endurance racing) reliability.

I still think the way to go -- other than going the Abarth SS route -- is to use as much stuff from the turbo engine as possible and pop on a Rotrex blower.

 

[randomizered]

Well, 7200rpm is the stock limiter from fiat. Sure the engine could take a little more.

Of course an abarth spec engine would be nice, as would the turbo spec 1368cc bits, but presently both are very rare and expensive, as is a rotrex at about £1300 on it's own.

I am living in the real world for now ... £100 ish to switch to itb's.

Literally 1 hour to switch between my current intake setup and itb's and 2 maps on the megasquirt is a nice easy job

If and once working I may get two power runs made, or borrow an accelerometer again for a comparison.

 

[StoneNewt]

Piston speeds for 84mm stroke (1.4 SuperFIRE)

6,000rpm = 3307.087fps
6,250rpm = 3444.882fps
6,500rpm = 3582.677fps
6,750rpm = 3720.472fps
7,000rpm = 3858.268fps
7,250rpm = 3996.063fps
7,500rpm = 4133.858fps
7,750rpm = 4271.654fps
8,000rpm = 4409.449fps



4750fps = F1?

Generally -- depending on who you talk to -- 3,500 or 4,000 are regarded as upper limits. In full race trim (and with full race rebuild schedules) it seems the 2 litre twin cams can be run at 7,250 for brief periods, but that's with forged pistons, one peice valves, bronze valve guides, peened rods, special bearings and a re-worked crank.

fps? surely you mean fpm & 5000fpm has been exceeded on BMW, Honda & Toyota engines in race trim. Also your maximum piston speed drops as you put more stress on the engine so a fairly low-strung 1.4 16v engine shouldn't have much problem dealing with occasional forays beyond 7000 rpm. My turbo has seen the far side of 4100fpm on occasions & is still alive.

Just looked the stock Elise 111R has max power at 7800 rpm on a 85mm stroke, that's 4350fpm, iirc the limiter on those is 8200 which is just shy of 4600fpm.

 

[fingers99]

fps? surely you mean fpm

Yes, my bad.

5000fpm has been exceeded on BMW, Honda & Toyota engines in race trim.

But for how long -- and I'm presuming these were -- as you say -- in race trim. How many miles/hours between rebuilds?

Also your maximum piston speed drops as you put more stress on the engine so a fairly low-strung 1.4 16v engine shouldn't have much problem dealing with occasional forays beyond 7000 rpm.

The first bit makes no sense at all: piston speed is a function of rpm, nothing more. It's true that loaded up the piston and rods are less stressed than when unloaded, but they're unloaded during every cycle. Rods break under tension, rather than compression.

My turbo has seen the far side of 4100fpm on occasions & is still alive.

On occasions...........

Point is, perhaps, that that engine has a long stroke, relatively low quality engine components, hydraulic lifters, and doesn't seem to breathe very well. A centrifugal charger plays to its strong points, revving the gonads off it is likely to expose -- perhaps catastrophically -- its weak ones.

 

[StoneNewt]

The first bit makes no sense at all: piston speed is a function of rpm, nothing more. It's true that loaded up the piston and rods are less stressed than when unloaded, but they're unloaded during every cycle. Rods break under tension, rather than compression.

If you think about an engine as an air pump, the more cfm through the engine at the same rpm the higher the over all load. If you increase the cfm when you're running near the point of destructive* piston speed & extra stress of those cfm may push you into the destructive* area.

* destructive is the wrong word but it gives the right concept. I can't think of words for what I actually want to be saying.

On occasions...........

Point is, perhaps, that that engine has a long stroke, relatively low quality engine components, hydraulic lifters, and doesn't seem to breathe very well. A centrifugal charger plays to its strong points, revving the gonads off it is likely to expose -- perhaps catastrophically -- its weak ones.

My engine is hardly standard either but the point is it's still working & going rather well.

The hydraulic lifters are the things I have no experience of with FIRE series of engines & yeah the 16v head doesn't seem to do to well compared to a fettled 8v head. As for a centrifugal charger, iirc their efficiency map is rev biased if you get the gearing right for your cars red line/limiter.

 

[fingers99]

Yeah, take the point about the air pump. But for the rods and pistons (temperatures excluded) the critical stroke is the the exhaust stroke -- no pressure to slow the piston up and it has to stop dead and reverse direction.

Other nice thing about the centrifugal blowers is that they should put much less stress through the drivetrain that a roots type, including the crank pulley (which may be where DaveTheTrike's Punto met its doom).

 

[StoneNewt]

Yeah, take the point about the air pump. But for the rods and pistons (temperatures excluded) the critical stroke is the the exhaust stroke -- no pressure to slow the piston up and it has to stop dead and reverse direction.

If you're pushing more cfm, or more importantly lb/min at this time, there will be more tendency to go to a lower pressure in the remaining air gap at piston direction change due to air mass momentum making the problem even worse. As you increase cfm you put more stress on the engine at virtually every stage of the cylinders cycle, not just compression & ignition stages though those do have the biggest stress increase.

Other nice thing about the centrifugal blowers is that they should put much less stress through the drivetrain that a roots type, including the crank pulley (which may be where DaveTheTrike's Punto met its doom).

Never said that they didn't have an advantage over roots blowers, in fact imo & they give a much more realistic efficiency curve for when you want performance. I mean even in the V70 with peek torque down in the 1700rpm area I'll still drop two or three gears if I want to over take something cause it's generating a lot more power at 4000-4500rpm than 1700-2250rpm

 

[fingers99]

Mind you -- I love my neice's Works Cooper S mainly because it just responds to your right foot like a 3 litre NA car. (Runs out of go past 115, though..........)

The polis have no trouble at all catching me in their V70s, dammit.

 

[StoneNewt]

Mind you -- I love my neice's Works Cooper S mainly because it just responds to your right foot like a 3 litre NA car. (Runs out of go past 115, though..........)

The polis have no trouble at all catching me in their V70s, dammit.

You don't need much go much past 70mph anyway, so maybe pushing the go up from 115 to 130km/h would be a nice thing

Be interesting a police V70 v's mine. But I have a fair idea who'd win over a tank full of fuel

 

[randomizered]

Well, they arrived in the post today.

Perfectly spaced to the ports, couldn't have got it any closer if i tried.

They have 34mm butterflies, idle adjustment screws, individual butterfly trim, an electronic tps, and what i assume is like a warm up cable, that cracks the butterflies slightly more open and activates a switch.

Gonna be a few months to do this. I'm going to start by cleaning it all up lol.

The actuall throttle port area isn't much larger than the ports on the 1242 16v manifold, so i think it may work out well