Hoppy

While 350bhp is great, it's actually not much use at 7,000rpm. And to get it, you need a big, laggy turbo, bigger injectors, prolly a f/m intercooler etc etc. Lots of money, lots of compromises.

But at the other end of the rev range, could a UK00 car with standard turbo, injectors and intercooler some how be pursuaded to pump out 300lbs/ft of torque at 3,000rpm?

If that level of torque could be maintained, it translates into power figures of 172bhp @ 3,000rpm, 228bhp @ 4,000rpm, and 285bhp @ 5,000 rpm, buy which time it will start running out of puff but might still peak close to 300bhp around the 6,000rpm mark.

Looking at the dyno pages, compared to the fire-breathing 350bhp monsters, it looks like an engine tuned like this could be 50bhp up at 3,000rpm, putting out similar power at 4,000rpm, and only losing out at higher revs when the big turbo really begins to score.

In real-world driving, that looks like a higher-performance package than the big top-end bhp car.

Is something like this possible? Is there a better titanium turbo or something that would do the trick? I guess it would need some fancy turbo plumbing to make it happen safely and keep the car driveable (not a Dawes Device, then ). And is the clutch/transmission up to this kind of clout?

Yours in ignorance but hoping for a miracle (well, it is that time of year)

Richard.

john banks

I agree entirely Richard. Don't knock the Dawes until you've tried it - you do get used to the crisp boost response and Darren Dawes and others and myself are all working on solenoid control systems to activate it only at large or complete throttle openings. I am getting 17PSI at 2400rpm. I suspect this is the sort of response you are looking for. Try 50-70 or 55-75 in 5th gear in 5 secs (vs 8.5 unmodded same car). As stock the turbo was only just churning at 2500rpm - 65mph. I don't think you'd get 300lbft at PS, but you might get 290lbft at PE - I'm sure someone with PPP induction and DP got 293lbft peak torque on one of the more optimistic RR. As far as I have seen no Scooby beats a PPP running 17.5 PSI at around 3000rpm on stock turbo - except those with a daft initial overboost spike. Since the TD04 is at about peak efficiency at 17-18 PSI at these revs then all it needs is the fuelling and ignition timing to be right there and you'll hit the best torque possible? Or am I being too simple?

[Edited by john banks - 12/20/2001 8:07:52 PM]

milo

getting an ecu mapped, prolly with overboost at low revs would be a start. if you look at the dyno site, (iirc) the well mapped ecu cars tend to have a *lot* more torque low down (certainly i remember seeing before and after comparisons on adding a link giving huge gains low and midrange in the torque department). obviously depends on the ecu and mapper though.

and/or.. hybrid turbo (need a remap anyway), nitrous?, increase engine capacity?, all of the above?

depends how much money you want to throw after it!

for real-world driving improvements id suggest plenty of non-power related mods though (suspension, brakes, driver training etc)

john banks

http://dyno.scoobynet.co.uk/uk/bash_nazir.htm

I like the shape of this torque curve.

Hoppy

Milo, one of the reasons I like this approach is that you shouldn't have to throw lots of money at it as you're not generating big horsepower. I was thinking of a Link ECU and some clever boost management bits, maybe a trick little turbo.

As for real world driving improvements, I've got the brakes and Prodrive suspension done Wetter the Better quite a few track days, and been scared witless by Simon De Banke so it's probably as good as it's going to get in that department!

John, thanks for your comments. I'd love to believe in the Dawes MBC but a £25 ball and spring...? ("Trust me, I'm a doctor!" ) Maybe I just need the comfort of spending a few hundred quid. I certainly can't argue with your figures, though, and it has been some of your other posts which prompted this thread.

And yes, I saw that power graph a long time ago, and within a week I had a PPP and the ScoobySport down-pipe wasn't far behind. Well pleased, too.

I just want more of low-end torque. Can it be done?

Cheers,

Richard.

john banks

"Maybe I just need the comfort of spending a few hundred quid." But try spending £25 first! It shifts everything 500rpm lower and to my mind gets out of the TD04 all there is to be had. Fuelling is spot on, and hopefully the knock sensor and stock ECU are optimising the ignition advance. What more do you need? Go on try it.... Or if you want flashing lights and spend a few hundred quid then buy an AVC-R - then you can create your own preferred boost map. I still might do this. As far as I see it the only way to get 50-70 in 5th in 5 seconds is to keep the wastegate shut as much as possible. Not subtle but it does work.

[Edited by john banks - 12/21/2001 7:00:33 PM]

Sam Elassar

hi hoppy
what you say make complete sense. i don't know if you have followed any of my posts few months back reagaring the mods i have done for my car. i probably was one of the first people to go link,vf23,fmic (aps) on the net. my car has achieved great results on the rolling roads 320bhp/315lbf/ft at a day when standard cars were only producing 220bhp so none of that optimistic PE figures. although every one who drove my car thought it was brilliant i was not happy for various reasons and that is why i now have a new car

the reason i was not happy is because the power although came with a huge amounts only came later in the rev range. let me rephrase that, on paper every thing was only shifted by 300-400revs but on the road it ment the turbo took longer to spool up but when it spooled up it spooled up faster, does that make sense ?

if i had a choice to do the same thing with my scoob again i would do them in a different order really. the scoob does not like to have more than 300lbft or otherwise you start chewing gear boxes i have had 3 gearboxes!!!!!!!and i have never done qtr miles or anything like that, loads of track days though

one thing it bear in mind though is that standard TD04L turbo is just crapp end of story. it will only hold 1.2 bar up to 5500revs if you are lucky, if you try to run more boost with it your charge temps for sky high, useless.

what you need is a bigger turbo VF23 OR EVEN VF22 but with the addition of a turbo restrictor ala rally cars this way you will restrict top end power but you will push so much more air at the midrange and the turbo will spool up so much quicker. how do you think rally cars produce 400lbft at 2000-2500rpm ? while using huge turbos?

after that i would then check the charge temps, if they are high enough go for water injection. basically the whole aim of the exercise is to limit the top end power.

i am rampling now, i am sure i am going to get a lot of people tell me how wrong i am

steve rally

Sam,
Interesting theories there...

I'm running a Type R V4 Rally car in GP A trim (34mm Restictor) with GEMS mapped by self on Dyno.

The restrictor certainly reduces power!! as you are limited to circa 0.9 Bar @ 6000RPM (VF24). but it doesn't help mid range torque at all. We get this by using closed loop boost control (std on GEMS) and running 9.0 :1 compression ratios. Std STi is 8:1.Also when running these CR's you need 102RON fuel
We run approx 1.6 Bar peak with Water injection to keep things cool.

This gives us circa 370ft.lb at 3800RPM and never less than 300ft.lb from 3200 thru to 5400 then the restrictor starts to ruin your fun. So we have to concentrate on low /mid range torque to give decent GO.

Some of this is available to your road car (to answer the original question) but it needs a GEMS or similar mappable ECU and mods to pistons.It depends how much you want to spend!

Steve Rally

R19KET

Steve,

I suspect ALS helps too

John,

Although I haven't seen the TD04 compressor map, I'd be a bit concerned that 17psi @ 2400rpm may be over the surge line. If it is, you're taking a big chance with the turbo letting go.

Given your comments about it being in "peak efficiency", maybe you have the map, and I'm wrong ?.

If you do have the map, could you email me a copy,

Thanks, Mark.

john banks

Interesting Sam about the restrictors. I really like the TD04! I'm not going to change it as I don't want more lag. I don't really care very much what it does over 5500 rpm as it is a road car and spends relatively less time up there than it does in the turbo lag zone if it didn't really blow until 3500rpm. By the time you've changed down you've lost your gap or you are in a low gear waiting for an opportunity, but with a TD04 anything above 2400rpm and you can be at 1.2 bar. Would rather have some turbo over a wider range than a lot more in a narrow range. Just my opinion, but for a 2 litre single turbo road car it seems ideal. A hybrid or twin turbo setup would be expensive to buy and tricky to mod so easily, a larger capacity engine would weigh more. I find it sometimes very good to drive the wife's 3.0 six 406 as it really shows up how good bottom end response can make a huge difference on the road - this thing can pull away cleanly in 4th gear and is pulling pretty hard from 1200rpm. By the time it has reached 3000rpm it has put a lot of road behind it.

Thanks for the comments Mark about the 2400rpm 17PSI issue. I had been asking about it before to check it was OK and nobody questioned it. I would like to see a map also to know this is OK. It certainly pulls very well but obviously I want this to continue! Please tell me about the surge line. I have found some maps for other turbos of possibly similar spec. Do you know any rough equivalents say from Garrett that would give me an idea?
http://www.turboneticsinc.com/comp_maps/fig1.html Is the TD04L comparable to the T03? I wish I could find the map but I have been hunting everywhere - originally I was more concerned about the boost at the top end, but it drops to 13 PSI at 6500rpm and a fair bit more towards 7000rpm (which is rarely visits) which is what Theo had mapped for. Please also see a helpful posting here http://www.i-club.com/forums/showthr...12#post1279612

[Edited by john banks - 12/21/2001 11:14:01 PM]

Sam Elassar

hi steve
the restrictor will be reducing the overall power but does not help increase the torque at the expense of bhp ? getting 300lbft at 3200 is what hoppy wanted i thought. the VF24 is still a small turbo, i think you have tried on of these mark have not you ?

how do you think a vf22 hybrid with a restrcitor will perfrome obviously the size of the restrictor will be according to what ever you want to achieve.

an ecu is obviously a must and the internals will determine the bost level you run. i have run a UK scoop with link ecu and VF23 at 1.3bar and have done at least 20 track days on that period. with no engine problems.

john
you may be happy with the performance of your car but how do you know you won't like a slighly bigger turbo if you have not tried it yourself ? when i got my car back to standard, I HATED MY CAR. it is so slow as standard i can't believe i even bought it in the first place. if you can manage to run 1.2bar at 2400rpm on a TD04L you will be able to run the same boost at 2600rpm but you are still pushing more air and there for producing comparable power combine that with an ecu that allows you to run more iginiton advance in these areas ( you are pushing less boost but cooler denser air) and you will end up being faster than the standard tdo4l almost through out the all rev range.

sam
just saying my own experinece and nothing more really.

edit to say i have just looked at your link. 1.2bar at 2400 is very impressive, what gear are you talking about here though ?

[Edited by Sam Elassar - 12/21/2001 11:39:47 PM]

john banks

Fair point Sam. I need another ride in a big turbo car...

Sam Elassar

no john
you need to drive a big turbo car
there should be one or two coming up around scotland over the next couple of months, i am sure the owners won't mind you giving you test drive

R19KET

John,

I just saw your i-club post. I'll see if I can find a map from somewhere.

It may be fine, but your pulling in 17psi very early, so much earlier than stock, that I'd just want to be sure it's safe.

The best I could get with the VF24, was 1bar/14.5psi @ 3000rpm. Wish I could get that now I can "blow" more pressure than my turbo can at 3k, let alone 2400rpm, my turbo's in a bl*ody coma at 2400rpm............

Mark.

Sam Elassar

couple of interesting cars to support my point, the

EVO7 achievs higher torque figures and a flatter curve than the EVO6 by reducing the turbo nozzel ( that is why i suggest a restrictor) and by using a smaller turbine housing 9.7 instead of 10.5 apart from that they both use a TD05 16.6G.

falkland performance had the engine dynod which was mapped with autoronics ecu and a VF22 hybride with a restrictor achieved 330lb/ft and 330bhp at 1.4bar.

sam

steve rally

Sam,

Just to come back to your point about the restrictor giving more torque at the expense of power.

We tried mapping an engine on the dyno with 32mm and 34 mm restrictors (customer wanted to run in GP N someteimes) and the only difference was that the 32 started to give lower torque (and hence lower power) further down the rev range. Initial torque up to 5200 rpm was the same as the smaller restrictor is not having an effect.So I'm not sure that fitting a restrictor will really gain you anything.I wish I could run my rally car without it!!!

The point is that although you can play about with boost with the various devices available - and these will certainly help - to get serious low down torque you have to be able to control ALL the parameters affecting engine efficiency i.e booost,advance,AIT,fuelling,compression ratio.Obviously in terms of advance we are runnin about 1.5 deg from det point - I guess a std ECU runs considerably further away than this -this is how the PPP gets some of its improvements as it is simply a mappable MAP sensor voltage modifier-so you are limited again.Just out of interest we have found on the dyno that 1 deg of extra advance gives about 4% more torque.

On the EVO7, I have just mapped one of these - awesome!!Running 1.9Bar(YES!!)pistons,rods etc.I think the reason for the improved low down torque was the smaller turbo hence quicker spool up.Also from the amount of advance we could dial in it has a slightly higher Compression ratio??

Steve Rally

john banks

Can see that I can't compare a TD04L's boost pressure with a big turbo as the flow is not so good at the same pressure. But with newer cars possibly having higher or variable compression ratios and smallish turbos to minimise lag, I don't know it I could live with the lag of a big turbo. But I need to try one!

Sam/Mark - at what point did/do your cars produce 80% of maximum torque? Can't find a dyno for your car Sam?

If you find a compressor map Mark that would be hugely appreciated. Have scoured the web for one.

Sam Elassar

hi steve
thanks for the the reply, so that is my theory out of the window then so why do rally car manage to achieve their maximum torque so low down ?

to go back to the evo7 turbo subject. the E7 does not have a smaller turbo than the E6
Evo TME GSR - TD05HRA-15GK2-10.5T

Evo 6, TME RS - TD05HRA-16G6-10.5T
EVO6 GSR-TD05HR-16G6-10.5T
Evo 7 - TD05HRA-16G6-9.8T

so as you can see apart from the TME GSR which has the smallest turbo the EVO 7 only has a smaller exhaust housing.

if this is the reason to get the torque low down then why not get a custom hybride turbo with a smaller turbo housing and maybe that will achieve the 300lbft as low as you can get it. ultimitely this will also restrict top end power though

sam
just guessing

john banks

Sorry two subjects going on here. Hope no one minds!

Is the TD04L in the MY99/00 UK spec a TD04L-9B or TD04L-13G?

I now have maps for both here: http://www.3si.org/member-home/jluci...turboguide.htm




from the author comments they look slightly fudged but the only ones I can find! The first URL has other ones for other turbos.

Author has also overlaid volumetric data for another vehicle's engine, but the map underneath may be useful ignoring the straight line plots.

[Edited by john banks - 12/22/2001 11:05:47 AM]

Sam Elassar

hi john
here is link to 3 graphs
this one is the intercooler and the turbo graph
http://www.subarupower.co.uk/dyno/du...ler_graph1.JPG


this is the car just with the link
http://www.subarupower.co.uk/dyno/link18aug.jpg

this is the final map with every thing slapped on
http://www.subarupower.co.uk/dyno/st...ance323bhp.JPG



[Edited by Sam Elassar - 12/22/2001 11:21:55 AM]

john banks

Only the second one loads Sam?

Sam Elassar

try them now

john banks

Thanks - 280lbft at about 3200rpm is pretty respectable. I bet it feels good between 2800-3200rpm as that torque curve is like a cliff face turned upside down. Make a Dawes setup look civilised! So I am glad to see it is not just a top end monster. It looks like things would be be better on a well set up TD04 until about 3100rpm then, then at somewhere around 4000rpm depending on gear you would come flying by. This is of course unless you happened to be above 3000rpm to start with And of course after a high end gear change you would be off to the horizon. Interesting.

[Edited by john banks - 12/22/2001 11:54:25 AM]

Sam Elassar

hi john
link 18aug graph, the car only had a link ecu and fully decatted and cone filter (blitz). this was when the link was intially installed. running 1.2bar, ignoring the bit of deliberate overboost, the charge temps were rising quickly that the torque curve was declining all the time from peak.

if you look at the last graph with the intercooler i am still runing similar boost 1.25bar but although the turbo is taking so much longer to spool up i have got 275lb/ft of troque from 3000rpm now show me a car with standard turbo that can do that ?

the first comparison graph was when the intercooler was fist installed and i have only spend little time on mapping it.

i don't remember seeing any other letter preceed the TD04L but i will check for you.

Sam Elassar

true
but when you are booting it you are rarely doing 300-4000rpm and if you notice the intercooler graphs regain all that have been lost and you end up with even more power at the 3000rpm than with the standard small turbo

however it is not fun if you spend most of the time in city driving around in 2000revs band as it is kind of dead. then you hit 2500rpm-3000rpm and bang 275+ lbft hits you in the face

i am still to achieve anywhere near that with my new car at the higher revs.

john banks

I'd be interested to know where I could follow your progress with the Evo Sam. Could be my next car also.

Sam Elassar

no problem
i should be at most the rolling roads that are arranged around here. most the developments will probably be post on the scottish section though and not here, to aviod getting abused. i don't like the ltr it is very strange over there.

sam

john banks

It is a shame if you were abused. A lot of people graduate to an Evo, and I wouldn't know where to start. I know it is Scoobynet, but to me it is the community more than the make of car surely. If someone with one brand of four wheel drive turbo Jap saloon cannot appreciate another and compare tuning hints then what are we coming to! I even read Saabnet and Seat/VW rings occasionally - the different perspective can be very useful. As can reading I-club.

Sam Elassar

that is exactly what i think john
i appreciate all cars really. i mentioned before i wanted an R34 vspec but could not afford it. if subaru makes a car that i like i will be the first person to get one. easy i love jap supercar performance type cars for the price of a exec saloon what else do you want.

i think though some of the newer member to view like that they think one car can be best at every thing which is never going to be the case.

and your point regarding different tuning routes from the various boards is a very valid point. that is why te EVO 7 turbo was mentioned as an example

sam

Hoppy

Wow! Great replies So it seems that 300lbs/ft at 3,000rpm is possible, one way or another. I wonder what Bob Rawle thinks?

One other point - how driveable would a car like this be? The torque curve must rise almost vertically from 2,000 or so which might make dawdling around town a bit fraught - one second you're doing 30mph and 60mph the next Sam touches on this feature. Is this perhaps the reason why this kind of power delivery is not available from stock?

It reminds me of my Yamaha two-stroke bike, which when it came 'on the pipe' as they say, would keep accelerating even when you rolled off the throttle

Richard.