You really need to take it off to weld it up properly if its the standard unit im afraid Fergie, its possible to weld in situ but i bet it will be a bugger! and harder to clean the surfaces up as well.. plus while its off you can put welds in other places to help strengthen it as well i would imagine.

Sounds good Nigel, just hope it ready for TOTB

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A coop that would rev to 8k would sound very sweet me thinks can the bottom end, even uprated take it though as i havent heard of it before in the coop world...

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I would think the bottom end could take it, just would need to be balanced along with everything else and make sure you have double or tripple valve springs Look out for a certain 16vt which will do 8000rpm

All being well, I will be ready.

I'm only going for a GTA Walkers combo for the clutch, so I'm hoping it'll be OK.

As long as everything goes back together OK, the car will be back with me by 7th July for a thousand miles running in, then an oil & filter change, then a remap.

I've almost certainly decided that my hailstorm-induced respray can wait until after TOTB, as they wouldn't be able to book me in until the week after the rebuild, leaving me about two weeks to run the car in and get a remap.

I just have to decide who will map the car

PTS, Millway, Owen (do they still map Unichips?) or I might be willing to drive to Dastek if its worth it (would help put some miles on the car to loosen it up a little)

Owen only map them if they installed it IIRC...

Millway's RR is not capable of mapping cars over about 280 bhp and your torque will be a real problem for their rollers, also very poor cooling.

Owen Devs will only do the ones they fitted as they haven't suppled the Unichip for several years now. Get a Motec there though

So you are left with PTS, and we both enjoy their excellent customer service .

You could try Engine Advantages, Witham, Essex, Roger is thinking about using them.

I was warned off using the larger 16VT injectors (I have a set of 4) due to fuelling problems that can't be controlled by the Unichip (it's to crude) so I will be very interested to hear if you manage to use them and get a successful map.

H Andyi, I was also warned about mapping with 16vt injectors for the same reason.

If you have a quiet word in Grahams ear, you should be able to reduce all of the fuelling maps by a set percentage , and then map with that.
One of the biggest problems running big power and the Unichip is that you are beyond the capacity of the air/flow meter above 300bhp (you see the voltage max out), so the ECU has to rely on in built maps to 'guess' the fuellingand the more power you run, the more 'out' it will be.

Paul at PTS is aware of all these probs, and did suggest creating a custom fuelling ECU for the 16vt injectors.

joe

With the unichip could you not just use a better method to sense the airflow though as i know you can with teh motec and the likes but would think the UNICHIP should be able to make use of such a thing?

As far as I'm aware with the current unichip, the only real problem is above 5k where at that level the mapper has to 'guess' % of fuel to pull out.

We know the 16vt injectors are good for 400 - 420bhp so not too hard to control based on boost and the signal from the wideband during mapping.

Hello Juergen, I was referring to your car in my earlier post I’m glad you posted I think you’re the only person with a gt2871r fitted to a coop, could you please tell us at what rpm you hit 1 bar/14.7psi boost when in 3rd gear cheers dan.

Can they not get rid of this 'guestimation' by using a wideband lambda and seeing injector cycles and stuff? ie with the help of a wideband lambda and setup barnacle widgit?

Also do they not need to provide a little bit more on the 5th injector than the others as Iceberg has said itsn near enough always that one that goes due to underfuelling and he believes its due to the airflow and some other things into that cylinder...

Kingpleb, yep you can use a MAP sensor to get rid of the a/f meter issue, the new Unichip allows support for this, although I heard via Paul at PTS about a possible 'module' for the current Unichip.

Its easy to map, but in the absence of anything meaningful from the a/f meter then the ecu has to rely on throttle position, and charge temperature to guess load, the rising rate fuel regulator also allowing increased fuel pressure with increasing boost.

Other ways round the airflow meter issue is to fit a larger one of course, or house the current one, a tube within a tube of sorts so you can use its reduced air flow range to predict a wider range of air flow.

The MAP sensor is the ideal option though.

joe

ps I thought the 5th cylinder failing was due to having the shortest manifold branch?

Ahhh i wonder how much this module will cost for either version and then for the MAP and wiring. Im guessing you could salvage a MAP from antoher vehicle and nick the wiring loom from it as well but would mean the standard ecu wouldnt do much other than go off its maps for not getting any data from that then?

I have also bought a 2871rs 2 weeks ago, getting fitted next week...The engine internals are quite standard, and the turbo specialist suggested the 2871 is not more "laggier" than a 2860rs, and then you can always get more power from it if you want...So this became my choice, and cant wait to see what results i get next week after install/mapping

Dunno really, just going off what iceberg said to me. if anything it would help having the branch shorter i would think as getting the gas to the turbo still hot as poss and out as quick as poss...

This is a fantastic thread, the old forum had such 'nuggets', but this year there's been a dearth of such things,.. the tuning thread being filled up with dump valves and the like.

Its great seeing the variety of ways towards coupe tuning, and the 2871r and 3071r are fascinating , all credit to Nigel, Fergie, Stichl et al for doing this ,...... when I got my novitec chip 4 yrs ago, noone in the UK had fiitted one!!

yes, can't wait to see what power and powerband these cars produce, and how to overcome the various obstacles they produce.

regards

joe

Kingpleb, I wonder why the 5th injector would be weakest ?...

i too enjoy seeing this within the coop fold

It shows how much we commit to finding the best for our cars and tuner shoudl take note of it, we are no average scooby/evo owner just after a quick bolt on. we look at what else needs bolting on to compliment that bolt on

You know that feeling when you commit to spending a truckload of money on the Coupe?

I've had all weekend to contemplate my actions, and here's my conclusions.

Stichl - I reckon your car is not getting the best out of the GT2871R at the lower end (although there's clearly no doubting your top end performance - I'd be staggered if I got anywhere near your 397bhp). 4,250rpm spoolup is very late, and goes against what I've read from many other applications on other cars.

Yogisdk - we'll have to keep in touch and compare notes - I can't wait to see what your car gives after mapping.

I've read MANY threads about GT2871 spoolup on many different car forums, and I'm clinging to the fairly common belief that on a car with a decent VE (ie 90%+), I'll get spoolup at the same or earlier than I would with a GT28RS.

My estimation is that with the cams and headwork and straight induction, I'll have a significantly better off-boost drive anyway, so even if I've got a 500rpm later spoolup, it would pi$$ me off too much.

Perhaps I'm just trying to kid myself that I'm not just about to turn my previously tractable Coop into a lag-monster. Only time will tell, but I'm sufficiently confident with my decision that I WON'T be nagging Turbo Dynamics on Monday morning with a load of "have I done the right thing" questions.

The only two issues I have now are

1) I've read that the 2871 doesn't come with a wastegate actuator - certainly they didn't ask me what pressure I wanted it set at (going for 0.8 - 0.9 bar) - so I guess I WILL be calling them after all

2) If everything comes together, there's a slim chance I might be pushing over 350bhp, in which case, my choice of clutch will be suspect (GTA / Walkers combo) - however, I absolutely MUST have a clutch I can live with for everyday commuting and rush-hour stop / start traffic. I remember Joe's trials and tribulations with his paddle clutch, and I'm NOT going down the same route.

It's like being 8 years old on Christmas Eve - I can't wait

I would have gone with ATP for the turbo as god knows how much TD want for it although it does mean it should arrive at your house ready to be bolted straight on.

I hope im wrong with the lag issue but i suspect even with your mods your spool up will be higher up the rev range than even what mine is at the minute with the standard induction route....

As logn as you make good use of the rev limiter in TOTB and such like i cant see the spoolup affecting you much

The clutch should still last i reckno as logn as its not daily your dumping the clutch for launchs or suchlike i dont think you could go any higher up anyway unless you found a good clutch from a diesel engined car to take the abuse as its more the torque i think that kills them off and the new VNT diesels can cope well with high amounts

I bet by lunchtime TD will have had a good long chat to you to assure you that your credit card can be relieved of said money and it will all be fine

PS Im a sceptic and i have far too many irish attributes in me that people confuse with scottish ones. Must be why i got LPG anyways

Hey Nigel

Sorry to ask but what is VE??

I was (am) also worrried about the lag issue, but talked to the main turbo people here and all went to say the 2871 is not going to be laggier than the 2860 in the coupe...I guess we will see, i guess all comes also down to how much boost you want from it, but i believe 4250 rpm before boost sounds doubtful ( i hope so!!)

I guess the actuator you can set it up yourself, i dont know what boost it comes from factory but i know there is one in mine, as i have it right here in front of me in its nice Garrett box

What is ur FULL BOOST rpm kingpleb?

Ross

how do u mean fullboost? i run about 1bar peak at the minute and i think that is just over 3000rpm at the mo. id need to check on my way home though as i need to swap tyres over now the weather has closed in as slicks and rain dont do well

Nigel,
A couple of points to consider which people may not agree with. Firstly on my car the headwork I've found makes a small improvement to spool up but really shows its stuff at higher revs, so I'm not sure you'll see that much difference.Secondly the 2871r will be laggy compared to the 0.64 RS, I'd say it would probably be laggier than the 0.86 RS and for the benefit of a headline figure I think would give you a better utilisation of available power.I also know of guys that have fitted this to 4 cylinder applications and all of them commented that below 4k it is flat as fart. If you want a drag strip monster then I'd guess you've gone down the right route but for a daily driver I reckon you'll be disappointed. So to summarise, cams won't really affect spool up as VE is relative to revs/volume of air, headwork in general gives most benefit at higher rpms and the straight inlet will have a positive effect but overall . Without dragging up forum history, can peeps remember the debates over the 28RS with the 0.86 housing?? most 'experts' suggested it would be to laggy for real world use and yet more and more people are fitting them and without doubt this side of 4k the 2871R would be down on power compared to a 0.86 RS

Jamie

I'm not the most technical when it comes to turbos, but other point to bear in mind is the cars gearing.

My rev limit is 7200 and if I change from 1st to 2nd any earlier than that, I fall out my efficiency window. Not good when your drag racing

Hi Nigel,

Is it the 48 compressor trim, 0.64 a/r turbine housing version of the GT2871R?

The 71 turbos have the same tubine options as the 60's but bigger compressor wheels, so the 71 will spool up slower than the equivilent 60, but support higher flow rates.

Has anyone looked at fitting one of the GT2860R's for the R34 GT-R or R34 GT-RN1?

Fergie you're right, I'd guess you need at least a 3000rpm power band.
All you have to do is either calculate it with the gear ratios, or more simply, rev the car in
1st,2nd, 3rd etc to redline then change up and see what t
e revs are, then that is where you still want to be in the power band.

joe

I keep wondering, why would it be so laggy as people claim, when it has the same turbine size as a 2860rs, but a biger compressor housing? I am therefore thinking it will spool as fast as a 2860rs, while being able to blow more air...

Ok hear are the figures. at 2.5k i see 0.5bar, at 3.2 i see just over 1bar and then quick shoot back down to 0.9/0.8 its hard to tell when your travelling that fast...

This is all done in 5th gear as well. One scarey thing i found out on the private bit of road i often use. i can hold 140leptons without any boost now thats scarey and thats with no known headwork, no cams, no induction mod...

The longer i own this car the longer i fear for my licence i can say if thats what i can get on a small private strip and hold for a mile or so without worry on an autobahn these things must fly quickly with these kinda mods! Im guessing the CD of the car helps as well

I still think you would be better off with the .64 housing RS Nigel as you dont need massive power for everyday use and fot TOTB you can work on traction more and other things too, ie track tyres and stuff