Xr6t BA vs ls1.... Both unopened

[Solone]

My bf xr6 turbo 6 auto is a hell of a lot quicker than my ve afm ssv. In fact there it is even more obvious during roll on acceleration

maybe with a fair amount of boost but stock for stock?

I drove them back to back and the VE SS more than held its own, might have been slightly quicker.

But this is about BA XR6T and LS1. Generally cars you can get under $12-15k

[lumina ss]

I drive them both every day the ford is quicker above 20 k/mh the Holden below

[Solone]

Some fairly basic maths and a lot of assumptions, springs ignored, etc.

LS1 = 5.7Lt

XR6 = 4.0Lt (NA). Assume 5PSI of boost and the engine will "consume" 5.33Lt of air. Take that assumption to 10PSI and the motor now consumes 6.66 Lt of air

Boosted motors also tend to hold their torque peak longer giving more "under the curve".

?

not really... turbo doesnt come on until 3000rpm and its all over by 5800rpm.

LS1 grunts harder under 3000rpm, has better gear ratios and is happy to rev out to 6500rpm.

You analagy would be fair if the XR6T always made the boost ie 10psi at 2000rpm and held it to 6500rpm.. which it dont.

[185iboy]

I highly doubt that is stock bottom end the ford 4 litre turbo motor whilst can pull good figures in particular a BA the weak point is the con rods for the amount of power and boost it would need to run that number the stock rods will snap

I know that he's been working at it for a couple of years he's one of the best if not the best backyard xr6t tuner. If it was a built motor he would've run numbers straight off the bat not working 10th's off since 2009

[OUTAtheBloo]

How much is the budget ?

[LuisS]

not really... turbo doesnt come on until 3000rpm and its all over by 5800rpm.

LS1 grunts harder under 3000rpm, has better gear ratios and is happy to rev out to 6500rpm.

You analagy would be fair if the XR6T always made the boost ie 10psi at 2000rpm and held it to 6500rpm.. which it dont.

Ok ,I tune both - so gimme a chance !

We need some "rules"

In the chasing the "unopened" title days , there wouldn't have been 1 single LS1 that didn't have mafless tune & valve springs as a minimum.

So , opened / unopened - what's allowed?

Are we comparing tuned cars or straight off the factory floor ?
Are we keeping this 'BA' XR6T vs LS1 or allowing BF ?

[Solone]

Ok ,I tune both - so gimme a chance !

We need some "rules"

In the chasing the "unopened" title days , there wouldn't have been 1 single LS1 that didn't have mafless tune & valve springs as a minimum.

So , opened / unopened - what's allowed?

Are we comparing tuned cars or straight off the factory floor ?
Are we keeping this 'BA' XR6T vs LS1 or allowing BF ?

Let's keep it to ba xr6t vs ls1.... No valve springs, no opening rocket cover. Bolt ons and tune. Basic mods that most people will stop at.

[LuisS]

Let's keep it to ba xr6t vs ls1.... No valve springs, no opening rocket cover. Bolt ons and tune. Basic mods that most people will stop at.

SO - We compare LS1 VY to BA Mk1

LS1 path to HP - extractors/ cats , cai , tune = 235 to 255 rwkw
N/A so no need for bigger injectors , factory valve springs are generally no problem to 6500 rpm
Take it to the track : Auto 3.07 diff , unless it has a stall convertor and/or diff gears it will run mid/ low 13

BA XR6T path to HP - boost! depending at what stage the valve springs stop closing the valves, a std BA will handle anywhere from 8 psi to 12 psi ( very dependent on age/km's) - hence this is one of the main things in the list.
240 odd kw is the upper limit on std injectors , so that is normally the first thing to change. For peace of mind , in-tank walbro pump & 60lb injectors . Big power gains from E85 on these , so that's another easy "bolt on" ( 60lb injectors no problem on E85 to 300+ rwkw)
So assume we run 8 psi
Take it to the track : Auto has 3.46 diff , hold it on the handbrake to build boost for launch , will run a high 12/ low 13

fit some valve springs , Cat back exhaust , bigger intercooler , torque convertor - up the boost to 12-13 psi - 11 sec car

[Solone]

SO - We compare LS1 VY to BA Mk1

LS1 path to HP - extractors/ cats , cai , tune = 235 to 255 rwkw
N/A so no need for bigger injectors , factory valve springs are generally no problem to 6500 rpm
Take it to the track : Auto 3.07 diff , unless it has a stall convertor and/or diff gears it will run mid/ low 13

BA XR6T path to HP - boost! depending at what stage the valve springs stop closing the valves, a std BA will handle anywhere from 8 psi to 12 psi ( very dependent on age/km's) - hence this is one of the main things in the list.
240 odd kw is the upper limit on std injectors , so that is normally the first thing to change. For peace of mind , in-tank walbro pump & 60lb injectors . Big power gains from E85 on these , so that's another easy "bolt on" ( 60lb injectors no problem on E85 to 300+ rwkw)
So assume we run 8 psi
Take it to the track : Auto has 3.46 diff , hold it on the handbrake to build boost for launch , will run a high 12/ low 13

fit some valve springs , Cat back exhaust , bigger intercooler , torque convertor - up the boost to 12-13 psi - 11 sec car

it does seem that the valve springs on the BA XR6T is the deal breaker. diff gears will add nothing for the XR6T but make a big difference on the LS1.

[zorro]

I beg to differ on diff gears, desperately need to shorten 1st gear and even with converter no need to labour the thing to boost get it there and happy days. Again speaking from mucking around with these things.

[Solone]

I beg to differ on diff gears, desperately need to shorten 1st gear and even with converter no need to labour the thing to boost get it there and happy days. Again speaking from mucking around with these things.

Check out www.xr6turbo.com.au, many guys on XR6Ts have tried the diff gears without any success. The load on the turbo is less with more mechanical advantage of diff gears, so spool time is increased and it dont spool as hard.... Some even go backwards with Rwkw. By the time the turbo spools up the revs are too high and its time to change up to next gear, so rpm range is less too. More load and more rpm range from the stock diff gears is the reason why the turbos go no quicker with diff gears.

how many ls1 turbos run the 3.9 gears? same issue here, these guys usually go back to 3.46 to even 3.08s.

[whitels1ss]

SO - We compare LS1 VY to BA Mk1

LS1 path to HP - extractors/ cats , cai , tune = 235 to 255 rwkw
N/A so no need for bigger injectors , factory valve springs are generally no problem to 6500 rpm
Take it to the track : Auto 3.07 diff , unless it has a stall convertor and/or diff gears it will run mid/ low 13

BA XR6T path to HP - boost! depending at what stage the valve springs stop closing the valves, a std BA will handle anywhere from 8 psi to 12 psi ( very dependent on age/km's) - hence this is one of the main things in the list.
240 odd kw is the upper limit on std injectors , so that is normally the first thing to change. For peace of mind , in-tank walbro pump & 60lb injectors . Big power gains from E85 on these , so that's another easy "bolt on" ( 60lb injectors no problem on E85 to 300+ rwkw)
So assume we run 8 psi
Take it to the track : Auto has 3.46 diff , hold it on the handbrake to build boost for launch , will run a high 12/ low 13

Hey Luis, with that example I think you are spending more money on the XR6T....
I reckon for the same money you are spending on the XR6T you could fit a stallie and a set of 3.9 diff gears
(or even on a budget some used 3.46 gears to just be on equal terms?)
Then the VY LS1 will run into the 12's also

[Solone]

Hey Luis, with that example I think you are spending more money on the XR6T....
I reckon for the same money you are spending on the XR6T you could fit a stallie and a set of 3.9 diff gears
(or even on a budget some used 3.46 gears to just be on equal terms?)
Then the VY LS1 will run into the 12's also

should look at it on equal dollars spent..

So full exhaust/intake/tune is about same cost on both sides..

if we go injectors and fuel pump on the xr6T then go diff gears on the LS1.. We have an evenly matched car wouldnt you say?

I think its only when XR6T gets valve springs that it starts to step away, but at this cost, LS1 gets a cam.

[fishman88]

ive driven my mates xr6t ba auto tuned. It had valvespring float at 212rwkw. Goes great when boost kicks in but nothing at the start. Doesnt even chirp tyres off the line. We did a rolling start in 2nd gear from 60 kmh and mine killed it and pulled away. Mines got 3.46 hsv exhaust and otr maffless tune. didnt cost me too much as i sourced parts second hand. The SS is alot more fun on the street. Not sure what the results would be if he changed his valvesprings and pump about 240rwkw.

[Micks]

Guess it comes down to what your happy with either a Ford 250 6cyl Taxi with a baby snail attached or a Holden with a 346 V8 Chevy NA. I know what I prefer!!