Calling for LS advice and recommendations

[DangerousDerek]

So now is finally the time to turn to the dark side.

I intend to twin turbo an LS. I had in mind a LQ4 6.0 but have been offered a 4.8 which is from a 2003 Silverado and hasn’t an iron block and ally heads.

Any reason I should steer clear or shall I pull the trigger and start making this happen?

[DangerousDerek]

TVRMs said:

The more common the conversion, the more useful and available the advice. Go with the engine most commonly used to upgrade similar cars Derek

I aint trying to build something common though.

[DangerousDerek]

RichardD said:

That is a LR4 engine then?

From Wikipedia standard output from the 4.8 is 285bhp (a very RV8 number), so I assume you will be looking for lots of boost (16psi up)?

http://www.superchevy.com/how-to/engines-drivetrai...

shows that 100bhp/litre is do-able with the short stroke by changing heads, cam and intake .

Budget Boost! http://www.gm-efi.com/tech/budget-boost-low-buck-t...

Edited by RichardD on Friday 13th October 09:18

Thanks for that Richard, certainly looks like a strong motor as standard to take some boost.
I hated seeing that these baby 4.8s can be found for $250 in the states. Ive been offered one fully dressed and delivered to my door for £2750 and I am seriously considering it.

[DangerousDerek]

RichardD said:

I didn't realise until a few minutes ago, it is an iron block.

http://www.turnkeyenginesupply.com/lr4-4-8-remanuf... Not sure if you know/mind(?)

Out of interest what transmission would you plan to link up to a LS? (To perform well on the strip...obviously )

I would like a 6 speed but al the drag racing lads tell me to go auto!
A 4l80 might be too big to fit but a glide is much smaller and bullet proof.
Not sure I want an auto for what will still be a used car on the road and track

[DangerousDerek]

jesfirth said:

Do you really want a heavy iron block in the front of a tvr? That will make a right mess of the front rear balance

I will simply place 80lb in the boot. That will even it up.
I am sure with 700 bhp+ it will hardly notice.

The engine is bought, he talked me into it with talk of short stroke, lond piston dwell, huge bhp numbers etc. I couldn't resist especially after bargaining the price down.

Finally Its actually going to happen at last. I can use these at last...

[DangerousDerek]

GreenV8S said:

Locaterfield types seem to handle quite nicely despite a nose heavy weight distribution. I think the main drawback would be a lack of traction, and if this goes as well as I hope I think that's going to be a problem regardless of the weight distribution.

I use Mickey Thompson drag radials. There wont be any traction problems on the strip but granted its going to be a handful if I go anywhere near the boost of the road tyres.

[DangerousDerek]

77racing said:

Dereck Hi, I run a Quaife 69G behind my LS3 with Geartronic's flat shift ecu. changes gear in less than quarter of a second and it's manual shift

Why do I feel that sounds very expensive?

[DangerousDerek]

RichardD said:

Congratulations, you have a base for lots of possibilities! What make/models are the turbos out of interest ?

Thinking back to the 1/4, with a manual box you will wanting to be maxing out in 3rd or 4th at the end... (3rd may be tricky due to rpm required.)

With the right cam, and uprated valve springs it should be good for at least 7200 rpm.
The hairdryers are genuine Garret GT3076r good for upto 600 bhp each.
I will only be running them at 10psi for the first season. Honest.

[DangerousDerek]

RichardD said:

More rpm the better (assuming power isn't dropping off too much) .

Am sure you already know, you should typically get (very) low 10's with just under 700bhp and a 'chunky' T56 (slightly slower shifting than the T5), crossing the line in 4th.

Weli reckon I can dip into the 9’s and maybe a mid 9 with say a bar of boost.

Think I will be using MS3 pro

[DangerousDerek]

RichardD said:

I did a quick model / calc which resulted in a 10.1 (680bhp) with a high 1.5x 60ft time too, so I definitely agree.

Do you think lag may be any sort of issue (in the first couple of gears) and ... if so (!) are you planning on keeping your NOS equipment as a sort of "anti-lag" just in case ?

Richard, I have already done a 1.55 second 60 foot time. I plan to make a few changes when I sort a diff out that can take the punishment. I expect to be deep into 1.4's

[DangerousDerek]

norris_83 said:

4.8s and 6.0s can handle some good boost with no problems (14~16psi) if tuned right. But the latter will help spool up the turbos and give you a much better torque curve.

That build is going to be a monster! Would love to have a race once I get my car out of the warehouse and road legal.

I will race anything! I find faster cars drag me along and I get my best times that way.

Hmmm I hope I don't suffer too much lag and not missing out on torque for not having a 6.0.
The car will weigh around 1250kg with me in it when finished so maybe a higher revving 4.8 is right for the car. I did a little research on the spec I am aiming for and think that boost will build from around 2500 rpm. Whatever it ends up I am sure it will be considerably faster than it has been on a nitrous injected Rover V8 and that's all that matters.

[DangerousDerek]

RichardD said:

When you gave me the models of the turbos I did a quick look on the www and they seemed popular for big power Evo's, revving to 8k. Imho a 3.0 bank could mean everything happening at lower than ideal rpm for straightforward gearing, so you having 2.4's is probably ideal .

I knew I had a reason but it was so long ago I bought these turbos. The proof will be in the pudding