Turbo spool up time [Archive]

paddy1ad

18-01-2014, 19:53

Hi Guys,

a bit of a newbie question, but I've recently bought a lovely Phase 1 with plenty of engine tuning, now having had it out for a quick blat today (nothing too heavy), I note the turbo kicking in around 4500 rpm, which is just when I'm wanting to change gear (the engine sounds like it's revving but will take more) and wondered if you can set the boost to come in at lower revs?

Thinking 2500 for example?

Or am I being a bird?

Jonny5

18-01-2014, 20:05

Its a T28 with a 285 cam iirc so sounds about right.
Just rev it harder and hold on to the gear till at least 7k :burnrubber:

w35ty

18-01-2014, 20:06

What turbos on it mate do you know?

Guybrush

18-01-2014, 20:09

Full boost @ what rpm?
What boost pressure does it get up to?

A standard t2 turbo will kick in sooner, but probably not a very good match to your cam.

paddy1ad

18-01-2014, 20:13

Its a t28 hybrid

I'm not too sure what boost etc as I say I'm very new to this turbo scene.

If anybody can offer advice on how to monitor such things, it'd be appreciated too.:ashamed:

paddy1ad

18-01-2014, 20:16

Again daft question I know but will the engine and turbo take going to 7krpm on a regular basis? And when I say regular I mean when I want a large smile :laugh:

I'm not going to thrash the nuts off it, but worth knowing...

I've had a (swear word coming) impreza turbo and was a little ignorant, just drove it and drove it without really wanting to know how things worked, although I did leave it ticking over after a heavy drive to cool the turbo and will continue with the R5

Guybrush

18-01-2014, 20:19

Pick up an analogue boost gauge from thunk auto/demon tweeks/eBay
Plumb it into the boost circuit that runs from the carb to the Aei (ignition) unit.
Find a place on the dash to install it, a pillar mount or in the space where the clock goes, etc.

Alternatively there's a picture somewhere that shows the standard boost gauge a half decent estimate of how much boost (in psi) you're running.

paddy1ad

18-01-2014, 20:22

Jonny5

18-01-2014, 20:25

The car is fitted with an AEM Wideband and is fitted to the dash, although I don't really know how to read it... Please don't shout at me lol

I've noticed it's quoting numbers of 12+ when at norman running, but when on full chat drops below 11 can anybody shed light on the numbers? I've tried reading their website but still seem to be struggling to digest the info :cry:

http://www.rtoc.org/boards/showthread.php?t=4761

:agree:

casper

18-01-2014, 20:27

The car is fitted with an AEM Wideband and is fitted to the dash, although I don't really know how to read it... Please don't shout at me lol

I've noticed it's quoting numbers of 12+ when at norman running, but when on full chat drops below 11 can anybody shed light on the numbers? I've tried reading their website but still seem to be struggling to digest the info :cry:

If this is josh's old car then i have been in it and it started to spool well before 4I will.5k more like 3k from memory.I will pm you my number.Give me a ring and i will tlak you through afr's and shit.

Jonny5

18-01-2014, 20:27

Alternatively there's a picture somewhere that shows the standard boost gauge a half decent estimate of how much boost (in psi) you're running.

http://i1066.photobucket.com/albums/u410/JonnyR5-2008/2013-09/2577C3FD-5C24-4755-91C0-90DDE1C6AEFE_zpsznvjuspi.jpg (http://s1066.photobucket.com/user/JonnyR5-2008/media/2013-09/2577C3FD-5C24-4755-91C0-90DDE1C6AEFE_zpsznvjuspi.jpg.html)

:)

Rob1980

18-01-2014, 20:31

The way that you want to drive you car is very similar to me. I have got a slightly smaller T25 turbo with a 270 cam. It will rev up to 7k no problems and is at full boost by 3.5k revs. The larger T28 is a very laggy turbo and really does need to be reved high to enjoy it. I'm getting old so that's not for me and it sounds like it does not suit your driving style. Maybe consider a T25....?

Regarding AFR's. WOT I believe that you need to be looking at high 11 low 12 with your set up.

paddy1ad

18-01-2014, 20:35

Great feed Jonny5

Thanks Casper will bell you tomoz as the misses is mithering me to put this laptop down now lol

Cheers again guys for the quick and helpful posts.

GTphil

18-01-2014, 21:22

As has been said, the engine in this car has been geared to make power high up the revs.

It's a 60 trim T28 turbo, T25 core with a .42 cosworth cold side and a .49 Tomcat hot side.

The cylinder head has had loads of work done originally by bb-tuning.

The 285 piper camshaft has been most definitely timed up with some retard.

As for fueling it's the carb that I set up for my raider.

120 main jet
.9 air corrector
1.4mm second stage
1.7 needle valve

It's also got an efi fuel pump and an adjustable fuel pressure regulator the base fuel pressure is set at 6psi with the reference reading taken from the compressor housing on the turbo;)

This same set up fuel's on my engine for 24lb of boost right through each gear upto and beyond 7k rpm in fourth gear.

This lump breaths a lot better than mine (because of all the headwork) so may not be as rich as my engine high up the revs. The only reason it isn't running massive boost is because the actuator on the turbo is not strong enough.

So all in all it's been built to be a power house, from memory it's currently running 18psi so the afr's may be slightly rich and costing power but adding safety.

At the end of the day the 1.4 8valve pushrod motor was never designed to be revved massively all the time. But rest assured from when we have had it on the rollers it wants to keep on making power the more it's revved. So for me 7k plus every now and again for that "big smile" isn't to much of a problem :)

Hope this helps and if you want any more info/advise don't hesitate to either ask on here or pm me:agree:

GTphil

18-01-2014, 21:36

Ohh and for me I would say buy a -34 actuator and take the car to efi parts for a set up for 22lb boost plus and if it doesn't break you will be smiling all the way home. That's for sure:wasntme:

Goobie

18-01-2014, 22:00

if it doesn't break you will be smiling all the way home.

Pretty sure this is written in the small print of every invoice I've had from Renault. :cooter:

GTphil

18-01-2014, 22:03

Pretty sure this is written in the small print of every invoice I've had from Renault. :cooter:

Indeed! :laugh:

paddy1ad

19-01-2014, 08:28

GTPhil you're a legend..

Really would love to meet up with you one day for a crash course on engine components...

But in the meantime, thanks for the helpful detail.

FYI, I'm changing around 4.5k rpm and still enjoying the kick, but certainly no more than 5k

TNT ANDY

19-01-2014, 10:35

Brigsy

19-01-2014, 16:53

Rev it to 7k all day long. It will be fine. You need to rev it hard with a t28 to get the best out the engine.

GTphil

19-01-2014, 16:55

:laugh: Some typical RTOC advise above :agree:

In a good way of course ;)

Trevhib

20-01-2014, 15:57

As the others have said, you definitely want to be testing well into the 6000's on a regular basis with that set-up. :agree:

I wouldn't go beyond 7000rpm too often but then I'm risk averse :wasntme: