Power Curves

Author
Discussion

VinceM

Original Poster:

1,895 posts

138 months

Wednesday 5th August 2015
quotequote all




Thought I'd share the results of my power run at SRR at the weekend. Graphs should be fairly self explanatory. Bottom graph is the flywheel figure - question I have is that this is meant to be around 100 over at the wheel figures, so which one of these is more accurate - I guess the "at the wheels" figure would be as that's what's being measured directly.

Recap of set up/mods: 2004 LS1 Monaro VXR wortec cat back with 100cell cats and 1 7/8 LT headers, VCM intake (not OTR), MAFLess remap, MF heads (LS2/6 5 way CNC ported), 222/226 (0.605" lift) cam.

Curves are very smooth as you can see, some final tweaking to the mapping needed which should be done this weekend.

So my question is, does this look about right (I guess it does, I'm asking for an opinion) and what more can I get in the future? No funds for FI, so am thinking FAST or similar with 102mm TB. I like the way the car drives now, save for some slight roughness at cold first thing in the morning.

300bhp/ton

41,030 posts

190 months

Wednesday 5th August 2015
quotequote all
Flywheel figure, take it with a pinch of salt. You can't get a reliable flywheel figure from a rwhp figure. All you can do is guess.

Quick estimate, but they must be assuming 18-19% bhp loss through the transmission. Too much if a manual, but close enough ballpark maybe for an auto, but as I say, only take flywheel figures as a broad estimate.

rwhp figures should be accurate, but remember only comparable to figures measured in the same way, corrected in the same way and on the same type of dyno. Dynojets notoriously give bigger numbers than other types of dyno.

Have you ever had a dyno run with it stock? 5.7 LS1's in the US tend to get around the 300rwhp mark stock on Dynojets. Would have thought a bit higher with the cam & heads. But without that baseline figure from the same dyno, it's not easy to tell.

EDIT:

I was thinking of manual cars. If yours is an auto, then scratch what I said.

VinceM

Original Poster:

1,895 posts

138 months

Wednesday 5th August 2015
quotequote all
Thanks - I did have a base line figures of a standard VXR LS1 with Wortec cat back and K&N panel filter with 2 hole mod and that was 316bhp. That is at the wheels.

R8VXF

6,788 posts

115 months

Wednesday 5th August 2015
quotequote all
AFR seems to be all over the place in the first graph to me.

KMud

2,924 posts

156 months

Wednesday 5th August 2015
quotequote all
I would have expected a little more, but maybe your intake/TB is a bottleneck. Are you coming to TR? We've got the same cam, but you've got ported heads and I have the 102mm TB/FAST. I don't think your AFR need drop below 12 for an NA setup (I'm aiming around 12.6-12.8, RPM dependent), but I'll let someone more qualified comment...

ARAF

20,759 posts

223 months

Wednesday 5th August 2015
quotequote all
I know that we often say a 100hp lift for transmission losses on these cars, but the loss will decrease as everything wears. I think you have a good few miles on yours now, so the gearbox and diff will not be wasting as much power as those on a new car.

As has been said. Take the fly figure with a pinch of salt. It's the RWHP that will matter, and the area under the plot. smile

I agree that your IAT AFR is a bit rich for N/A at the end, but as these engines create so much heat, a bit of petrol quenching might not be a bad thing.

Edited by ARAF on Wednesday 5th August 21:49

SturdyHSV

10,095 posts

167 months

Wednesday 5th August 2015
quotequote all
ARAF said:
I agree that your IAT is a bit rich for N/A at the end, but as these engines create so much heat, a bit of petrol quenching might not be a bad thing.
IAT eh? I think you mean AFR beer

monkfish1

11,053 posts

224 months

Wednesday 5th August 2015
quotequote all
Definitely needs a decent intake, or more accurately a bigger TB. Stock LS1 TB will be holding you back.

ARAF

20,759 posts

223 months

Wednesday 5th August 2015
quotequote all
SturdyHSV said:
ARAF said:
I agree that your IAT is a bit rich for N/A at the end, but as these engines create so much heat, a bit of petrol quenching might not be a bad thing.
IAT eh? I think you mean AFR beer
yesredface

jameshsv

5,844 posts

160 months

Wednesday 5th August 2015
quotequote all
I can vouch for the 102 fast intake with matching 102 TB

VinceM

Original Poster:

1,895 posts

138 months

Wednesday 5th August 2015
quotequote all
Yes the afr is a bit wild but hopefully that will be resolved soon.

Thanks for the comments etc. Whilst I think the intake is the next logical step what is the thinking behind this? Is it from experience or is there something in those graphs I'm not seeing. My learning curve is a fair bit steeper than that power curve lol

maxmc2

2,061 posts

185 months

Thursday 6th August 2015
quotequote all
The AFR readings would show the constriction up somewhat plus the know of how the ls1s are in general.

VinceM

Original Poster:

1,895 posts

138 months

Wednesday 19th August 2015
quotequote all
monkfish1 said:
Definitely needs a decent intake, or more accurately a bigger TB. Stock LS1 TB will be holding you back.
TB on it's own or the intake and TB combo?

ArnieVXR

2,449 posts

183 months

Wednesday 19th August 2015
quotequote all
Read that article Stevie posted on intake manifolds and then buy this:

http://www.ebay.com/itm/07-08-SILVERADO-1500-INTAK...


KMud

2,924 posts

156 months

Wednesday 19th August 2015
quotequote all
ArnieVXR said:
Read that article Stevie posted on intake manifolds and then buy this:

http://www.ebay.com/itm/07-08-SILVERADO-1500-INTAK...
...and a cowl hood? smile

stevieturbo

17,262 posts

247 months

Wednesday 19th August 2015
quotequote all
That's the problem with the truck type intakes...they're huge !

When you flick through all the graphs, the Weiand one seems to offer the best balance between performance and cost in an OEM style fitment

Seems to retail around US$500-550. FAST is probably a little better, but maybe $300 or so more

R8VXF

6,788 posts

115 months