dynamix

iTrader: (3)

considering transmission is all new i think that is reasonable.. guess it will get better before it gets worse

MikeWood

Nice figures dynamix but I think we all need to be a bit careful here by not jumping to conclusions.

The performance package for the 06MY STi is quoted at 320ps & 450Nm based on work we've done on our engine dyno and the likely figures you'll get on a rolling road. The rolling road figures are conservative though so what you'll see may be more (or less) depending on which one the car's on.

To get a feel for the variation you are likely to see I've visited several different dynos (although not Clive's, I may have a long drive to do in the near future ) with the same cars over the last few weeks and if we take the STi as an example, we found variations in the figures of over 25bhp and over 50lbft between the various dynos. This doesn't mean that any particular one is wrong, just that there is a variation and it's not possible to judge the relative performance of different cars on different dynos. And before anyone asks, the figures quoted aren't the highest recorded, they are pretty close to the lowest.

To assess the improvement made by any modifications, the only way is a before and after on the same dyno, on the same day preferably so the conditions will be constant and on the same fuel. Even then the difference found may not be the complete picture as it's possible to vary the results slightly by getting the fan in a slightly different place or tying the car down a bit tighter or not having the wheelbase quite the same or running in a different gear as it now spins the wheels on the dyno in 4th!

The rear silencer on an 06MY is very similar to the previous versions and whilst it is restrictive, I honestly don't think that it's too bad. Changing it to something much less restrictive might give 10bhp, certainly not 30+bhp. The main reason the 06MY is quiet is the new centre pipe fitted (the same as 05MY JDM actually) which now has a very free flowing silencer that is shaped to fit the floorpan in order to get the maximum volume in the space available.

Regards

Mike

T5NYW

iTrader: (4)

Mike,
Any excuse to get out the Office and drive the Car LOL

It is the best way

Dynamix,
Did anyone have readings off a STD MY06 there as may give you a fair Idea of your gains

Tony

dynamix

iTrader: (3)

unfortunately not - i was the only 06 there

Gary C

I was supprised to see 117bhp lost in the transmission.

So thats why we need 300bhp just to keep up

dynamix

iTrader: (3)

will be doing a run on another dyno soon to see what diff is there - powerstation probably.

dougwrx

I dont think you have grasped the idea of how it is converted. When the car is on the rollers the first calculation is the wheel figure then they do a run down in neutral to find how much is being lost through the transmission , this is given as a percentage of the wheel figure. This is then added to the wheel figure giving the flywheel figure.


Dougie

evonorth

on the evo's we work with a 24% loss

dougwrx

I usually use 25% as abase figure but after being on numerous rollers with mates of mine in different types of cars the loss generally came out nearer to 30% than 25%.

ricardo

It depends a lot on what type of dyno it is.

For example, on the Powerstation one mine showed:

wheel power: 197 bhp
drag power: 119 bhp
engine power: 316 bhp

On that basis the drag power is about 37% of the total power, or looked at another way you add another 60% to the wheel power to get the total.

Others I've seen the numbers for have pretty much the same breakdown. On the other hand the drag numbers from a Dynojet dyno are pretty different - while the calculated power is about the same.

LitchfieldImports

Don't forget the drag figure includes the dyno and it's rollers so a different dyno will give a different drag read out. I think a DynoJet has just 1 roller under each wheel so the drag figure will be lower.

evonorth

The 24% loss was done on the dyno dynamics, like the wrc tech type, someone bench dyno'd an engine and it came out that the 24% loss was about right

Neil W

Dynamix,

Just out of interest, what mpg are you getting with your mods. I been trying to find out what to expect from an MY06 Sti with PPP.

dynamix

iTrader: (3)

get on average 25 to the gallon (mixture of road runs and spirited driving ) - much better than my previous bug eye STi

on the track at snetterton though got about 7mpg

MikeWood

Neil

On a recent journey of 214 miles which included several dyno runs I needed 40 litres to refil the tank. Hardly typical usage but should be fairly representative of what you'll get with 'spirited' use as dynamix puts it

Regards

Mike

Neil W

Cheers

Seems to be quite a noticebale improved difference compared to my 03 Sti then.

dynamix

iTrader: (3)

i even got 300 miles to one tankful recently whist doing my "driving miss daisy" impression.

you will find that this is because you dont need to thrash it to hit the power band - the power comes in much much sooner and is so much easier to drive within it without worrying about dropping off boost.

take one out for a test drive - or borrow Mike's for the weekend

Neil W

Cool. Already tested one and have one on order with PPP. Still got a couple of weeks to wait for it though.

dynamix

iTrader: (3)

well done you will love it - the centre diff is very stiff so dont be put off by it grabbing, knocking or spinning a wheel whilst on full lock at parking speeds though... it does loosen up a bit but when it is rolling this is a masterful box of tricks.

ex-webby

Mike,

My modified Spec C does 250 dead to 50 litres (I know as I ran out during the Optimax shortage ).

Must be in the mapping!

Regards,
Shaun.

bigknd

Yep mines exactly the same, I find it better to switch the DCCD into manual (lowest lock setting) whilst reversing stops the grabbing

Davey P

iTrader: (1)

Flippin heck that's good

Neilo

why can i get well over 300 all the time??? i certainly dont hang about!

Neil W

Yep cant wait to get it now and get it run in. Not sure what you mean about the diff grabbing or spinning a wheel!!!

When I tested the car I asked about the C-Diff but did not get a good explaination of when I would use this apart from "on a track so for normal use just leave it in Auto".

Also did a search on here but got further confused with C-Diff, DCCD-A etc etc.. Is this the same thing.

Tuts

I made 224 at the wheels on my 03wrx but corrected it came out at 276 which gives approx 18% loss, which is a bit on the low side i know.

Losing 114 brake seems a bit on the high side though. Do you think they were overly optimistic in the drag to make the figures look better? 35% seems like a lot.

I don't want to put your car down but if the drag is quoted as higher then it makes your car look better.

Or does it mean that I'm actually running 350ish on an exhaust and remap?

MartynJ

Dont be daft......lol....It's a Mahaa Dyno.....Read into that what you will....lmao
Mahaa....Accurate....

dynamix

iTrader: (3)

neil

john felstead is the expert on the dccd and there is an awesome thread of his explaining what it is and how to use it.

http://bbs.scoobynet.co.uk/showthread.php?t=143750

well worth reading it.

ex-webby

MartynJ,

Have you done any testing of different rolling roads including MAHA and DD ones! I have found BOTH RR's to give flywheel figures very close comparing with each other.

MAHA RR's are designed to give flywheel figures, so it is not conducive to compare drag and wheel figures from other different types of RR's.

Regards,
Shaun.

ricardo

Sounds like someone with an axe to grind....
So Powerstation/Litchfield did the development of the T25 with a crap dyno then ?

ZEN Performance

The PS dyno seems relatively consistent (as consistent as others anyway). It consistently gives a high power loss, but much of this is though the tyres themselves, and a function of how the car sits in the rollers as much as anything else. It's been done to death on here, I would take the flywheel figures, and no bother comparing wheel figures unless it's with a another car using the same gearbox, same tyres and run in the same gear with about the same sort of power, on the same dyno.

Other dynos are more focused on putting out a wheel hp figure that's comparable to the road. But the PS Maha unit gives very similar figures for transmission loss, 90-120hp depending on the exact car, pretty much all the time.

Paul