It drives just like it used to - nice and smooth on part throttle, easy round town, quite soft off boost (cams don't seem to have made any real difference here)

It only goes mental when full (or near-full) throttle is used.

I'm still struggling to get the boost settings right (or more accurately, the gain settings). I managed to cock up earlier today and got 1.67bar

Far more impressive though, when I managed to get it to give me the boost I asked for (1.55bar) was the way that it was still givig 1.45 at the redline.

I've been so used to the boost tailing off, that the experience of it still pulling VERY hard is just surreal.

Also, the lightened pistons and matched rods, together with the lightened flywheel, means I've been finding the rev limiter rather a lot - including through Queensway tunnel in Birmingham - the other drivers must have thought there was a Harrier jump-jet coming through

This is going to sound slightly dramatic, but on Top Gear tonight, I heard a car that sounds VERY similar. The Gallardo V10 has definite undertones of a Coupe engine at full chat

If you hadn't guessed by now, I'm rather chuffed with it all.

That Gallardo did sound nice.

Mmmmm - cant wait to hear this Nigel.

I might be going to TOTB this year to have a look/listen at all the lovely cars - and especially your new beast.

James

congrats Nigel! Fantastic result !!

I wouldn't worry about the spool-up on a dyno - that's just a symptom of a larger turbo requiring more load to spool it up, so the dyno will never give you a fair representation of spool-up unless its fully loaded up.

I guess that leaves you a week to get used to it handling-wise for TOTB.

How does it feel compared to your old Ferrari?

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How does it feel compared to your old Ferrari?

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Is been 2 years since I sold the 355, so my memories have faded a bit. However, the best quarter I ever managed in the 355 was a 12.86 and in the Coupe, a 13.37, so the Coupe was pretty close a year ago. Given the launch advantage of RWD with mid-engined weight distribution, I reckon the Coupe was fairly close to the 355 from 30 - 130 anyway.

However, there's now no contest - the Coupe would pull away from a 355 in a straight line from a rolling start - I guarantee it. Stick a bend or two into the equation and it would all change around though.

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I guess that leaves you a week to get used to it handling-wise for TOTB

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Hmmm - the car certainly behaves differently now - it'll be more difficult to use a lot of throttle in the corners as it'll just light up the inside wheel when it comes on boost. Additionally, the later spool-up could well slow me down.

Its a real shame the TOTB handling circuit isn't a lot bigger, as my car excels at very fast (130+) cornering. I guess if the circuit is anything like last year's, I probably won't get out of second gear. However, I don't suppose Adam McQueen's winning CRX turbo is particularly gutsy at the bottom end either, so it'll be the same for allof us.

Also, I have a dilemma - I was treating my tyres (the 16" on my stock rims) with rubber softener on Sunday and I noticed a nail in the shoulder of one of the rears. Its leaking a little bit of air and in the position its in, a repair is impossible. Do I run the sticky tyres on the handling circuit only, and maybe even the quarter? I don't fancy hitting 140+ mph on the top speed run on tyres with a nail in.

My plan for the day is a couple of top speed runs first while its relatively cool, then a couple of quarters, then the rest of the day attacking the handling circuit.

As long as you're easily in boost rpm (5000rpm+) then the extra spoolup time/response time will not have much effect on the handling. From my experience with a similar amount of power it's just a case of being a lot more sensitive with the throttle and trying to keep it spooled up during the corners (which I'm not great at doing).

The handling circuit is heavily biased towards 4WD cars IMHO.

One other thing you may want to practice is gearchanges as larger turbos lose boost more quickly without load so the gearchange becomes more crucial for a good 1/4m time as does ensuring no wheelspinning before gearchanges.

Anyway, I'll be there on Sunday cheering you on like loads of other people on the forum so best of luck!!!

John

James - thanks for the offer, but I'd much rather keep matched tyres on the same axle. I'm running rather smooth Bridgestone SO2's on the front and Toyo T1-S at the rear. I guess seeing as the nail is in the rear, there should be little risk of it being pulled out.

I'll probably use my everyday 17" wheels for the top speed run - brand new T1-Rs on the front

Nigel, I've got your graphs now, just got to scan them, although I think they've posted the originals to you.

I've also got Frag vs Nigel graphs as well, so peeps can compare the gt28rs to the gt2871r, might make interesting reading

Joe

can't wait to see the graphs Joe.

390bhp is all very well, but as we all know, its area under the line that makes for a fast car, NOT just the peak power.

I have a feeling that the comparison will only show my car making gains after about 5,500 rpm, when I'm still pulling nearly 1.5 bar (and where I guess even the GT28RS is starting to tail off)

Something I'd forgotten to make a point on - it would appear that a 0.64AR turbine housing is plenty big enough to produce big power. The smaller housing is clearly small enough to make the car driveable, but has no problems pushing a far bigger compressor.

hehee when I got to Pts, I was told Paul was in the back of the workshop, when I got there Paul was giving the Dave the rundown on your car!!


Your absolutely right, the gt28rs producing more low down torque and the gt2871r producing more higher up, in fact, they intersect about 5500rpm as you say, and are then like a mirror either side of this, gt28rs in favour of low down and gt2871t in favour of higher up.

He did the runs in 4th and 'loaded' the rollers for about 9 seconds during the power run, so prob somewhere in between 3rd and 4th gears on the road to get an idea of spool up comparisons.

I will be able to scan them later.

Maybe Flea will care to host the picture?

Joe

Not a bad guess then

I always suspected that going to the GT2871 would probably cost me a little in bottom end grunt, which is a bit of a shame, as low down torque makes a car feel like it has a much bigger engine, and makes for an easy fast drive.

Confining the power to the top end makes for "interesting" progress, but is probably less easy to drive.

I must admit, I saw a small supercharger on the bench at PTS and thought to myself that if it could provide say a bar of boost from 1,500rpm up to 3,000, then it might be a worthwhile mod.

Where's that credit card

Send it on through Joe

Nigel, I've sent the graph to Flea, then we can have a look at the two power curves

Joe

Nigel, as an extra precaution, get yourself a can of puncture repair goo, and maybe put it in a day before your run to coat all inside surfaces. Just make sure you check your pressures after using it, as it continues to rise for some time .

I had a puncture before my sprint in April, and used the can to fix it. Worked well, and despite a 50mph limit, it went on to do over 5000 miles, a sprint, two trackdays in the UK and trip to the Nurburgring and two trackdays at Spa.

Oh, and the usual advice about it being a nuisance when it comes to changing tyres didn't seem to apply, the insides of the tyre looked fine and clean once removed.

Joe - just had my printouts from PTS

They show the final run with 389.3bhp @ 6491rpm and 326 lb ft torque at a very high 6117 rpm

biggest surprise though is the ambient temps at the time of the run. I knew it was hot in the dyno room, but the LOWEST temp measured was 40 degrees - the highest was 55

Also slightly unexpected was the power at the wheels - 327.7 bhp

Come on Flea, get a move on I want to see the graphs.................

Jules.

Calm down, calm down... I've done my bit Joe will be with us shortly

I've only got the one link, that's my torque curve compared to Nigels , sorry. I just took photos on the curves and superimposed them.

Nigels got the bhp plot.

I'll put the link up later on the tuning thread.

calm down Guys

Joe

OK - here's the power graph:

389bhp at 6491rpm at 1.5 bar

Fantasic result Nigel, cant wait to see it in action.

Nigel, was just looking at your graph

Just to think of it

by 4200rpm, you are developing the maximum power of a standard Coupe

by 5000rpm, you are now producing power of a healthy tuned coupe at 300bhp , just starting to get into your stride!

by 6000rpm, at 370bhp you are now starting to go beyond the most powerful 2 litre cars on the forum, (me and Flea )

At 6500rpm, all others are left behind....wooohoo!!!

joe

Nigels torque curve

joe

Thanks fraggers.

Ross