Adam M

It does completely, thanks wrexy.

except for one thing . If that is the case which Ibelieve it should be, then how can people so easily say 4.44 is better than 3.9. surely it is torque curve and power curve dependent.

iON Performance

Adam M - It's totally application dependant. When I mentioned a shorter set, this is implying that more of it's time is available to get in the "sweet spot" for power. Undoubtly, both cars will require changing gears before hitting the end of the run, however the car that does this sooner will have more of an advantage. This is all assuming that you've maxed out the gears on the way down the strip.

(Hypothetical situation, modelled after import drag cars in north america)
ie: (car 1, 3.9) -> (1/20 distance in 1st, grabs 2nd covers 2/10 the distance, grabs 3rd and covers 3/10 the distance, 4th and now covering 4/10 the distance so ~66ft left and you have to either cruise to the end in 4th or change over into 5th).

(car 2, 4.44) -> (1/20 distance in 1st, grabs 2nd covers 3/20 the distance, grabs 3rd and covers 1/4 of the distance, grabs 4th and now covers 4/10 the distance, so now we're seeing ~200ft left and ofcourse you won't cruise to the end, you'll grab 5th at this point to get to the end).

In the case of car 1, when 5th is engaged at ~66ft away from the end, power has dropped to the lowest portion and has very little time to climb.

In the case of car 2, with 5th is engaged at ~200ft away from the end, there's still plenty of time for it to move up the powerband to it's "sweet spot".

One better way of comparing two cars is by actually looking at a log of the actual shift points in relation to distance and time. This will give a good indication of how long each is in which gear for allowing a better measure.

Given a run of 1km or even of 1/2mi the 3.9 car should theoretically come out on top.




[Edited by iON Performance - 4/15/2003 11:34:48 AM]

Adam M

No problem with what you said above at all. That is what I was imagining.

I still dont know how it is so easily possible when asked the question, which is better 3.9 or 4.44, to so emphatically say 4.44 without looking at the cars spec in detail.

Is it a case of you have seen it so many times in practice that you have a feel for the better choice for the the type of engine.

Since our engines are so different in specs I would have thought that such a deicsion would be much harder to make.

ChristianR

iTrader: (1)

May I suggest starting a new thread and mergeing some of these posts into it? As these posts do not cover the original question asked. Which was:

"Is any one running one of Lateral Performances hybrids turbos? Spoke to Mark today and seem quite tempting to go for what I think was a VF turbo with garrett internals. Would be most gratefull if I could get some info of people which are using his turbos?!!?
Thanks"

iON Performance

Adam M - the response to your initial question was in context. That being said, drag cars are specifically design to reach top speed/terminal velocity at the end of the strip. Hence having everything else equal, a car which has a 3.9 when changed to a 4.11 or 4.44 will allow more time in the "sweet-spot" of the power band. Ultimately, fewer shifts will result in less time off throttle. However these fewer shifts must be at certain points on the track which allow for maximum usage of it's power curve.

Larger displacement or even higher revving w/ the 3.9 though should make up for this difference as then the time spent in the "sweet-spot" would be more equal to a car equipped with 4.44's.

In anycase, it all plays into a trade-off between hi-speed crusing, and just all out acceleration.

Given a stretch of tarmac long enough, all things being equal, the car equipped with a 4.44 will be crusing at several hundred rpms minimum over that of a 3.9 equipped car.

Andy.F

Christian - How is it a VF turbo if it has garrett internals ? Just retaining a P20 exhaust casting does not in my mind make it a VF based hybrid
If it's a garrett turbo core using a P20 housing then surely it is a Garrett based hybrid.

I recall bob called his latest turbo a TD05 hybrid as it used a water pipe from one (at least he wasn't serious)

Andy.F

Adam. I agree that you can't just say 4.44 is better than 3.9 or vice versa. It depends on the car. My car was quick with the TD05 and top mount on the low gearing, that was because the power curve was 'peaky' and it dipped very little between the gears (4 shifts)

Now with the big front mount and more power I consider the close gearing is a drawback, the car now has a wider power band but dips more between gears, one less shift but using a wider rpm range of each gear would be of benefit to me. (I think)

To Clarify, where I say dips more between gears, I mean the time the boost takes to hit full pressure again after shifting, this is only 0.1-0.2 seconds longer than it was on the TMIC but that is an eternity in 1/4 mile racing ! One less shift will also add 0.5 seconds to the total 'on power' duration of the run. So if my average bhp produced through a 4 shift 11.8 second run was 380bhp then on a 3 shift run (assuming still in power band) would be 380*10.3/9.8 = 399bhp Thats going to take 2/10th off easily.

Andy

ChristianR

iTrader: (1)

Andy, I am confused why you asked me that question?

I am just copying and pasteing what the original post was from Weenie.

My reply at the top of this page (6) refers to this 1/4 mile talk we are getting in this thread -what diff etc... This should be in another topic.

Adam M

I think andy you may have meant me, but your comments are taken on board anyway.

Andy.F

Sorry Christian, I misread your post and thought YOU were thinking about a VF hybrid turbo

Try using [ quote ] [/ quote ] to save confusing the dopes like me

Pavlo

Andy,

On my car I maintain about 10psi during a gearchange, while it's bouncing off the rev limiter...

And no people, I don't do it all the time, don't try it at home, give your clutch a hug etc etc so on and so on

Paul

ChristianR

iTrader: (1)

I would have no troubles running a vf hybrid on a subaru.

With my car, I feel I am at my best with the turbo I have.

Anything bigger would be to laggy for my liking for Jersey, and I feel, anything smaller just wouldn't make the most of the 2.5litre.

I believe my car is almost at its optimal level for Jersey. All I have left is change my fmic and induction, as these are not ideal for the turbo I now have. Once this is done, I will consider the car finally finished.

Andy.F

"Finished" ?? A scoobs never finished, is it ? To stand still in this game is to move backwards at a great rate of knots !

That is assuming you want a 'relatively fast' car, not just a fast car

Turbo_Steve

Just wanted to post a thank you to you guys. I am learning so much. Fascinating stuff. Wish I could afford the expensive toys

Sorry: not wishing to Thread Hi-Jack. Just so much negativity lately thought it would be nice to butt in with something positive.

RICH WILD

Just to jump in here.

Any chance of you making an appearance at Well Lane 5 Alan?

I'd like to see your car do the business and there are a few places available now as some have dropped out.

Cheers

Rich

harvey

iTrader: (48)

ALAN G. Where are you? Sneaked off on hols without telling us???

AlanG

Hello all.

Back home again.

Holidays? Unfortunately not.

We've been down south organising and attending a relatives funeral, so haven't seen whats been happening in Scoobynet recently.

Richard

Okay, put me down for Well Lane V, this will allow a direct comparison on the day with some other fellow scooby owners and as always i enjoy meeting and chatting with you all.

Been interesting recently, using AP22 with Andys' configuration settings shows an *average* of 300 at the wheels which is some 35 BHP at the wheels up on the readout from my last Well Lane visit, this is with 1.5 bar boost pressure from 4500-700rpm. Certainly feels stronger than it was, but higher up.

There are a couple of things i want to check with this one in the meantime prior to it, so hopefully there may be a wee bit more.

See you all then, take care for now

Alan

harvey

iTrader: (48)

Hi Alan: From my notes from Well Lane when you ran last can you confirm I have the right figures for your motor, please.
It was an MD305 from Lateral and gave340bhp ish, hitting 1.5 bar and tappering to 1.1bar?
I think you are still on a VF Hybrid from Lateral? What spec is it? and what do you expect it to do this time?

AlanG

Hi Harvey.

Yep, MD305. (304 with a P20 ex. housing)
At Well Lane 3 it gave 340BHP, 324Ib ft, 265BHP @ wheels.

The following day when i met up with Andy F, his AP22 showed the car as having 260BHP at wheels, so seemed to tie up.

My turbo at the moment is a VF with a Garrett cover and compressor wheel on the front end and a P20 on the back.
I run 1.5 bar all the way to 7000rpm now.

Latest AP22 runs show the car to have on average 300 @ the wheels. Depending on air temp during the runs, it varied between 280 and 320BHP with a g-force of 0.38g - 0.5g, in 3rd gear.

Alan

Guinness

iTrader: (1)

Update.Lateral Performance IHI/GARRETT hybrid.Car ran 391bhp 356lbs/ft torque at 1.5bar of boost...Alan

Disco

Awesome stuff Alan well done. Excellent figures for just 1.5bar

carlos_hiraoka

..... xcellent results for a STi ver 3 .....

Tim W

iTrader: (1)

On stock internals too...

So that's the call I missed then

I see Pat get's a credit on the check out sheet too

[Edited by Tim W - 4/27/2003 11:39:01 AM]

Guinness

iTrader: (1)

You could say i'm Very happy

AlanG

Alan is very happy!!!

AlanG

I've heard a few bits and bobs about your car and am i right in saying the latest improvements are down to the change in ECU?

I've always baulked at the cost of Motec, but would you recommend the change to that from Link for the boost pressure you're running?

Alan...seeing his wallet emptying again......

Guinness

iTrader: (1)

Alan G,i bought the Motec as it came along at the right price and at the right time.I'm running the same amount of boost from when i was on the Link,only the map is a lot better(thanks to Pat and Mark).Also i was on the limit of what a 6 row link had to offer,so i've got an Ecu now that will take any further mods in the future,maybe a stronger engine one day...Alan M...

Tim W

iTrader: (1)

Note to self, must ask my car's mapper nicely for a re-map after the suspension is sorted...just to upset Alan

Guinness

iTrader: (1)

You will be pushing your luck on a uk spec...;D

john banks

What do you reckon I could get from my UK spec then?

[Edited by john banks - 4/29/2003 9:28:40 AM]