LS3 top end swap

[mikeyb1987]

ringram said:

mikeyb1987 said:

It's a 114 + 0.

Ah I thought that might be the case, that explains it

[mikeyb1987]

SturdyHSV said:

7k on stock LS2 bottom end, you'll be fiiiiiiiine, go for it!

6,800 at least, that's barely above idle

That's going to be a whole different car now, can't wait to hear it at Northampton

Ok, if you say so....

I'm going to ask John to temporarily take it up to 6,800- purely as an exercise to see if it still continues to make power. If it does, then next year I'll get some rod bolts, possibly a FAST intake (if needed) and wind it up to 7k.

[SturdyHSV]

mikeyb1987 said:

Ok, if you say so....

I'm going to ask John to temporarily take it up to 6,800- purely as an exercise to see if it still continues to make power. If it does, then next year I'll get some rod bolts, possibly a FAST intake (if needed) and wind it up to 7k.

The LS3 intake is very good from the factory as I understand it, so although a FAST will most probably give you some gains, they may be very marginal so a lot of £/whp.

Roger said to me 7k is fine, I'm sure he wouldn't want you to take that as a guarantee in your situation, but I'm certainly a bit more comfortable pushing mine having heard that, for what it's worth.

[mikeyb1987]

SturdyHSV said:

mikeyb1987 said:

Ok, if you say so....

I'm going to ask John to temporarily take it up to 6,800- purely as an exercise to see if it still continues to make power. If it does, then next year I'll get some rod bolts, possibly a FAST intake (if needed) and wind it up to 7k.

The LS3 intake is very good from the factory as I understand it, so although a FAST will most probably give you some gains, they may be very marginal so a lot of £/whp.

Roger said to me 7k is fine, I'm sure he wouldn't want you to take that as a guarantee in your situation, but I'm certainly a bit more comfortable pushing mine having heard that, for what it's worth.

The factory LS3 is very good- so much so that a FAST only really has tangible benefits from circa 4k onwards. I'm just pre-empting the potential inefficiency of the standard intake above 6.6k. I know the cam/heads are good for a few hundred more rpm, so if there are any restrictions in the next chunk of rpm, the bottlenecks are likely to be the intake manifold/filter/MAF.

[ringram]

Get John to tell you kPa at Key on and at WOT if there is a difference you will gain from a better intake setup by approx the % difference.
Its easy to tell if you have a restriction.
As mentioned the LS3 fast might give you 15rwhp if you are lucky. Is that worth £1000?

[SturdyHSV]

ringram said:

Get John to tell you kPa at Key on and at WOT if there is a difference you will gain from a better intake setup by approx the % difference.
Its easy to tell if you have a restriction.
As mentioned the LS3 fast might give you 15rwhp if you are lucky. Is that worth £1000?

Does that include cost of install and mapping too?

Luckily I got mine 'second hand' unused in box for £500 as bargain of the century

[KMud]

FAST + TB? + fuel rails? (+ installation? + map?). Quite expensive getting that bit of grey plastic on top of the engine. LSXRT/ITBs and cowl hood start looking like appealing options to my befuddled brain at that point.

[SturdyHSV]

KMud said:

FAST + TB? + fuel rails? (+ installation? + map?). Quite expensive getting that bit of grey plastic on top of the engine. LSXRT/ITBs and cowl hood start looking like appealing options to my befuddled brain at that point.

Can re-use TB and fuel rails and such, and installation is a doddle (rear lifting eye can get in the way, but as they're new heads this is probably easy enough to unbolt)

So then it's just the map that's expensive, but yes, overall given an LS3 intake it's not good £/bhp.

[mikeyb1987]

All very good points gents. It was only minor musings about a FAST.

I've decided not to push any further re rpm limit until I've had a good chat/debrief with John and AAS. I've reached my goal, and to be honest, I just want to go and drive the car
I'm sure it could do 420rwhp with a few more bolt-ons/lighter pulleys but, for now, I'm happy with what it's done.

[SturdyHSV]

mikeyb1987 said:

All very good points gents. It was only minor musings about a FAST.

I've decided not to push any further re rpm limit until I've had a good chat/debrief with John and AAS. I've reached my goal, and to be honest, I just want to go and drive the car
I'm sure it could do 420rwhp with a few more bolt-ons/lighter pulleys but, for now, I'm happy with what it's done.

Sounds very sensible, you'll be lighting the wheels up a lot already with all that power, the last 15 probably aren't worth the extra risk

[jameshsv]

mikeyb1987 said:

How many miles has your car got on it James?

99.000miles

[Gelf VXR]

I buying a bare stock LS3 intake and sending it to this guy below for modification, not ported, and getting it shipped to the UK.

He installes rods along the runner edge to smooth the air over the sharp lip which causes the air to tumble effectly reducing the runner diameter, it flows similar to a (ported in I remember) FAST 102, which has longer larger tapered runners.

https://www.facebook.com/RickCrawfordRacing

[MyM8V8]

ringram said:

mikeyb1987 said:

It's a 114 + 0.

Ah I thought that might be the case, that explains it

But it depends if he installed it straight up? (+4 meaning that 4 degrees advance ground in to the cam)

Great result BTW!!!

[Monaro5.7]

But what does it sound like gotta here the idle and reving. you will have a grin from ear to ear and all you will wanna do it let it over run when it will pop and bang. still love doing this on mine and I have had mine cammed for about 3 years now

Well done mate another car properly tuned with a cam

[jonnM]

mikeyb1987 said:

I'm sure it could do 420rwhp .

It may already be doing 420....your "before" run seems a bit low to me. Pessimistic dyno?

You need to get it down to SRR!

[ARAF]

Gelf VXR said:

I buying a bare stock LS3 intake and sending it to this guy below for modification, not ported, and getting it shipped to the UK.

He installes rods along the runner edge to smooth the air over the sharp lip which causes the air to tumble effectly reducing the runner diameter, it flows similar to a (ported in I remember) FAST 102, which has longer larger tapered runners.

https://www.facebook.com/RickCrawfordRacing

I thought the rods were for strength, as the central pillars are removed - so that you get the best of the LS2 design with the LS3 ports? I may be wrong though.

[ringram]

jonnM said:

It may already be doing 420....your "before" run seems a bit low to me. Pessimistic dyno?

You need to get it down to SRR!

Nope 320 is about right for an LS2.

If he can get a bit more out of it from RPM it will be interesting as he is "only" 20rwhp off a brand new GTS LSA as it is..

Who needs a girly supercharger and a £12k bill!?

[jonnM]

ringram said:

Nope 320 is about right for an LS2.

Standard maybe, but don't forget Mikey's car already had headers, sports cats, cat-back and a CAI

[ringram]

300 is std, 320 with a tuneup. 320 is what an LS3 std does IIRC
LS1 is about 260 standard, 330 fully maxed out.

But I take your point, should be a solid 400 at SRR too then.

[ARAF]

On Charlie's dyno, our standard LS3 was 329 - to the nearest hp, the same as SW02TEC's LS2 with headers, cat back, CAI and re-map.

Both done within an hour on the same day.