Chip

iTrader: (3)

Certianly looks like less boost on your one given that its only making 460lbft.

Also made 50bhp/lbft (490 vs 440) less at 5250 than Dougs did despite the larger turbo.


What boost was that on then? 1.8 bar or something like that I guess?

Chip

iTrader: (3)

T4 will hold on a little longer at the top end, you can see this one starts to tail off at 7K ish.
Doug's still on hyrdaulics and its a road car, so massive rpm isnt really what he is after.
For big rpm and still as or more responsive than your T4, a 3076 would be a better bet.

Lo@der

iTrader: (8)

pmsl at the tags already .

Chip

iTrader: (3)

Surprised its only a couple of people TBH, there are certainly far more idiots on here than just 2, so I'd have expected a lot more tags from them than that if anything.

I'm sure there will be more once the bandwagon is rolling, but at least its not cluttering up the thread which so far is mainly just people with a genuine interest in YB's which makes a nice change on PF, lol

Chip

iTrader: (3)

He offered when the reyland built and NMS mapped YB that was in there before this one melted a piston while Dave was out with Doug.
He certainly seems to have done a good job of it as its not had any issues at all since Dave built it and NMS mapped it again.
Not something he does for a lot of people I dont think, although I know he has been building his own big power YB's for years of course.

Lo@der

iTrader: (8)

Why does Doug's tail off compared to franco's which climbs to nearly 7000rpm ?


Not a dig at all , as I guess in a road car want mid range punch . Im just interested to know?

Chip

iTrader: (3)

Combination of the turbo size and the low compression mate, at higher rpm the 3071 simply cant fill the cylinder enough to really get the engine to work hard, and is also starting to be restrictive on the exhaust side as well so increasing pumping losses etc.

For higher rpm, without any doubt the 3076 is the one to go for.

If you look on the before and after graph above, you can see that dougs engine was just starting to dip below the old 3076 at the very top end, but obviously the extra 100lbft for most of the rev range is at a cheap price if it only costs you half a dozen lbft at the top for literally only a few hundred rpm.

If the compression was a little higher it would hold on a touch longer, but even then it would still not be going strong at 8K on the 3071 for example

Martin-Hadland

iTrader: (2)

At 5250 it has just on 2 bar boost, the difference is less than 40ft/lb as far as I can see (depends which graph you're using), what boost is 5250 at on your graphs? I should have done a really high boost run just to see.

Chip

iTrader: (3)

Oh, as much as that, I wasnt expecting it to need quite that much on the 3076 TBH at 5250 is pretty much where those turbos really love to be for starting to make good torque versus the 3071 IME

Yes on the earlier graph it was 40lbft, I was looking on the later one.
It was 2.4 bar peak and 1.9 bar held on that graph IIRC from what Doug said, not sure on the exact value at 5250 though, but would imagine its in the 2.2/2.3 ballpark based on those peak and held values, I'll try and find out for you mate.

Yeah it would be a bit fairer comparison then I guess as at the moment it looks like this 3071 is absolutely anhiliating your 3076 for most of the rev range and im sure that playing field could be brought more level with a bit more boost from the bigger turbo.
For track use in a RWD car, I'd take your one for what its worth though mate, better power at the very top end of the rpm scale is useful on track and if its rwd you dont want big torque spikes on track of course.
More isnt always more, but for dougs application he certainly seems to have a great spec now.

Martin-Hadland

iTrader: (2)

My main point was that the way they come on power is similar and not as the first dyno run shows. Anyhow its all good

B13 JUS

iTrader: (24)

when i spoke to karl about my engine he metioned this car in conversation regarding the .63
karl told me doug was melting the tips off spark plugs when doing high speed runs and when he investigated the egt there where far to high over 1000c i think) but doug still did'nt want to use the .82 housing as he did'nt want any more lag.
so what karl had to do was to add more fuel at the top end to bring the temps down but this was'nt he choice of the way to do it.

Chip

iTrader: (3)

It was the cams that were killing it before for spool more than the turbo I suspect in this instance.
The exhaust side was massive in particular on dougs previous setup.

The 3076 can work well without a doubt, you only have to look at Deanos from MAD to see that, on a very similar spec engine to Dougs, he made 560bhp IIRC and that was still on an old intercooler with high intake temps.

I personally like the 3076 and was telling doug to keep it and go to marks cams and intercooler setup and the vipec etc but then I didnt realise at that point that mark was going to make 520bhp our of the 3071 TBH, Ive never heard of any other YB managing that yet.

charlie luciano

iTrader: (3)

Wow goes to show that with a bit more tinkering you can get some more ponies, nice 1 Sheady another quality job

awesome turbo, I'm glad I bought one my car wants some more tinkering too


Luciano

Chip

iTrader: (3)

Yeah that makes sense, I can see why Karl wanted the .82, I had suggested the same to doug, and got the same response that he didnt want more power if it meant more lag.
Anyway, the good thing is now he has more power and less lag at the same time

james kiely

iTrader: (5)

thats stunning perormance ,i want one ,would it survive a freshly built 205 block

paddyrs

this is off topic a bit but here it goes i have a t34.55 and want a .63 housing were would i get one?

charlie luciano

iTrader: (3)

Check the cosworth parts room fella or try any of the traders on site


Luciano

Chip

iTrader: (3)

I dont see why not, the 205 blocks arent actually weak, only real draw back is if you are wanting to long stud.

Mike Rainbird

iTrader: (3)

About time Doug put his hand in his pocket and changed the cams that were originally specced for the GT35 that he first had on the car LOL.

As usual, top work from Mark .

Stu @ M Developments

iTrader: (12)

I may well disable tags on this forum as they only get used by idiots anyway.

Chip

iTrader: (3)

Why not just enable a rollover or a click event of some sort so people can see who posted them?

Would still be good for search engines when they are used properly, and would still be ok for good natured humour, but would stop the spineless wallys hiding behind them?

Mark 3D

iTrader: (29)

Thats would be a shame

sometimes they CAN be quite amusing!!!

DaveEscos

agreed!

Where is Doug these days? does he come on here at all anymore?

Martin-Hadland

iTrader: (2)

Yes,...... Charlie Luciano!

Chip

iTrader: (3)

No mate he doesnt, but he does use the escort forum apparently.

Shame, he used to be a wealth of both knowledge and humour on here!

CossieRich

iTrader: (1)

An impressive result indeed.

DazC

iTrader: (1)

On the subject of GT3071.82 turbos on an internal gate, my Dad's car made 444bhp and 420lbft at the wheels (4x4) on a Dyno Dynamics rolling road using one of these turbos. Peaks at 40psi (2.75 bar) and holds 37 (2.55 bar) on a 7.2:1 C/R, BD14 inlet and custom exhaust cam.

I don't have the graph to hand so can't tell you where it makes the power and how long it makes it for but it is still pulling up to 8.2k.

Chip

iTrader: (3)

You think its still making 2.55 bar of boost at 8.2K are you saying?
Cause when im quoting hold, im saying what the boost has dropped to at the limiter.
would be good if you could dig out the graphs, especially one with boost and power on it?

CossieRich

iTrader: (1)

What power is that at the flywheel then if its 444 at the wheels and 4x4?

Chip

iTrader: (3)

assuming that is true that it made 444bhp @ the wheels and was 4wd then it would be 560-570 bhp

Mike Rainbird

iTrader: (3)

Flywheel calculated figures are fictional (but everyone wants them, so this is what gets quoted LOL), would be much better to quote at wheels figures . Any chance of posting up the at wheels figures of Dougs?

DazC

iTrader: (1)

Like I said Chip, I can't be sure without having the graph in front of me but from memory it doesn't feel like the power is dropping off until you're up that way. The limiter is 8.2k and I do reckon the power will be starting to tail off before that as will the boost. I mean hold as in the stabilised boost level once the turbo has spooled and settled rather than the pressure it will maintain all the way up to the limiter.

If I can find the graph later on this evening I'll post it up but I'm not sure if it shows a boost curve. Only power and torque. It was about 18 months ago now.

CossieRich

iTrader: (1)

My point exactly Chip.

I don't know the % loss on a 4x4 cosworth to try and make flywheel figure from an at the wheel figure.

i knew it would be high as mine makes 411 at the wheels and its 2wd making approx 481 fly.

Chip

iTrader: (3)

Dyno dynamics uses .78 as the correction factor from wheels to flywheel IIRC in shoot44 mode.

So 522bhp quoted at fly means it measured 522*.78 = 407bhp @ wheels

I may be out by a couple of %, but im sure its not anymore than that.

Chip

iTrader: (3)

Its 15% in RWD IIRC

Porkie

iTrader: (1)

never EVER used one once. and proud of that!

just for spineless cowardly twats!

if its funny and not too offensive then why not just say it?

Martin-Hadland

iTrader: (2)

I tried to convince everyone to have wheels figures off me when I bought the dyno, I soon gave up as no one was interested in the lower figure.

Porkie

iTrader: (1)

good plan!

ECU Monitor Enthusiast

iTrader: (1)

Neil@FastFord

'Ow noes!

The tags were the best thing ever! Be it ones coming my way, or dropping T bombs myself. They always brightened up the day.

Shameless plug time, we have tags on the FF forum.

Plug and tears of sorrow over....something about YB's was being discussed i believe