21 Turbo I NEED MORE POWER !

[Iwannabentley]

Evening All.
I took my pase one 21 out today on it first meet at Haynes,
I had a tussle with a friends 200bhp mini and came a close Secound, I'm already suffering the consequences of this.
Mine has a full stainless system, kn and bigger jets (been told they're volvo ones, 10% increase).
Is my next route a bigger turbo and remap rolling road session?
Any info or suggestions would be great.
Thank you

 

[andybond]

You cant map the OEM ECU. You are going to have to go aftermarket for that. Its proper old school tech you are using.
You can wind the boost up a bit to around 17psi but you need to monitor AFR and knock really.

 

[DaveL485]

Any info or suggestions would be great.

Replace the downpipe and turbo housing and elbow with a Cosworth style housing and a mandrel bent 2.5 or 3" pipe like this (Ignore the external wastegate)






Sack off the OE intercoolers and fit a front mount cooler with decent size pipework, then up the boost to about 17psi.

 

[DaveL485]

This above will make a huge difference to response and engine breathing over 5000rpm, it'll rev a lot lot cleaner.

Also if you can find one get a R21 TXi throttle body, its a straight swap and is 55mm, which is +5mm on the turbo one. Doesn't sound a lot does it but...
Area = π r²
So Turbo is 3.1415 * (25.0²) = 1963.5
And TXi is 3.1415 * (27.5²) = 2375.8

Thats a smidge under 21% increase in the downdraught area of the throttle body from a 5mm increase in diameter. Again it'll help that top end breathability which with the OE car I always found really restricted.

 

[Iwannabentley]

Thank you,
I think I have an stainless downpipe, but will double check.
It has a "add on" style intercooler behind the o/s light.
Might sack these off and get a large front mount set up and up the boost.
Is there anywhere in the southwest that looks after these?
A side note, I've noticed over the weekend that the pump for the water cooled turbo side of things is disconnected!
The heaters don't pump out any heat, could it be low pressure in the system caused by not having this pump running?

 

[DaveL485]

I think I have an stainless downpipe, but will double check.

Doesnt matter, if its got the OE elbow and wastegate housing it'll be strangling it. Dump the whole turbine housing back and it'll flow LOADS better.

It has a "add on" style intercooler behind the o/s light.

Pic please? Thats probably OE, the 21 has two intercoolers from the factory, one in the OSF wing and one over the rad.

Is there anywhere in the southwest that looks after these?

No

The heaters don't pump out any heat, could it be low pressure in the system caused by not having this pump running?

No, this pump only runs with the engine off, it circulates water around the turbo after shutdown for 10-15 mins. There are a couple of possible issues, the pump is goosed (that would burn out the relay too), the impeller is jammed or the relay has had it. Does the pump run if you give it a 12v + and - direct feed to the 2 wires?

 

[Deleted member 486]

This above will make a huge difference to response and engine breathing over 5000rpm, it'll rev a lot lot cleaner.

Also if you can find one get a R21 TXi throttle body, its a straight swap and is 55mm, which is +5mm on the turbo one. Doesn't sound a lot does it but...
Area = π r²
So Turbo is 3.1415 * (25.0²) = 1963.5
And TXi is 3.1415 * (27.5²) = 2375.8

Thats a smidge under 21% increase in the downdraught area of the throttle body from a 5mm increase in diameter. Again it'll help that top end breathability which with the OE car I always found really restricted.

What's the part number for the TXi throttle body?

Guessing that the 12v manifold isn't a straight swap too?

 

[Brigsy]

This above will make a huge difference to response and engine breathing over 5000rpm, it'll rev a lot lot cleaner.

Also if you can find one get a R21 TXi throttle body, its a straight swap and is 55mm, which is +5mm on the turbo one. Doesn't sound a lot does it but...
Area = π r²
So Turbo is 3.1415 * (25.0²) = 1963.5
And TXi is 3.1415 * (27.5²) = 2375.8

Thats a smidge under 21% increase in the downdraught area of the throttle body from a 5mm increase in diameter. Again it'll help that top end breathability which with the OE car I always found really restricted.

Does the throttle body actually make any difference ? Megane has a pissy little 40 ish mm throttle body on it and its good for 4-500hp.

 

[andybond]

Does the throttle body actually make any difference ? Megane has a pissy little 40 ish mm throttle body on it and its good for 4-500hp.

100% with you on this one Brigsy. I cant see it yielding anything. Perhaps if you are scavenging the very last dregs of power but until then..

 

[DaveL485]

Does the throttle body actually make any difference ?

It does top end IMO when combined with the intercooler and exhaust mods. Can't compare it to a Megane, it's decades different in tech!

Guessing that the 12v manifold isn't a straight swap too?

Totally, completely and utterly different. It dwarfes the Turbo manifold, it's enormous.

What's the part number for the TXi throttle body?

NLA

 

[Deleted member 486]

It does top end IMO when combined with the intercooler and exhaust mods. Can't compare it to a Megane, it's decades different in tech!



Totally, completely and utterly different. It dwarfes the Turbo manifold, it's enormous.

View attachment 138919



NLA

Was just about to say the same about the throttle bodies. On modern cars with low inertia turbos it's not quite so important. On older cars anything you can do to reduce the pressure drop is a bonus!

I knew the 12v dwarfed it - just wondered if the bolting pattern was the same.

I bet there's one on a shelf in eastern Russia somewhere!!

 

[Brigsy]

Interestingly a r5gtt will make 235hp with 32mm throttle plate on carb. Stick efi and 50mm throttle plate on the same engine and it will still make the same hp. Id say you would only pick up a couple of hp at most with the larger throttle, so if its hard to find a txi throttle body then it aint going to limit the hp using the original ?

If i wanted more power out of a 21t id ditch the crap management for a good standalone ecu, then look at a modern turbo and hotter cam. All depends what you want i guess.

 

[andybond]

21t id ditch the crap management for a good standalone ecu, then look at a modern turbo and hotter cam.

You mistyped replace it with a 774

 

[la21t]

21 Turbo - My Current 21 In Pictures

It says "I AM A WANKER WITH A PRIVATE PLATE".

turborenault.co.uk

The 4 stages of me needing more power