Power Curve, Tune Manipulated?

[Boogieman98]

So the reason I purchased my FP Green turbo is because I like the way the power curve looked on others cars. For example this 2005 STi

http://forums.nasioc.com/forums/showthread.php?t=2771312

I liked how the power was peaking between 4500 rpm & 5000 rpm. But as you can see from my chart it doesn't peak until around 6500rpm



What could cause such a difference between the two? Can the tune do this?

 

[Alin]

[MENTION=9]HolyCrapItsFast[/MENTION]

 

[HolyCrapItsFast]

Refresh my memory... what turbo do you have right now?

 

[HolyCrapItsFast]

He has 280 cams and ported heads... That plus tuning could be the difference easy.

 

[Boogieman98]

I have 272 cams now but not ported heads. Do the cams move the power curve that much?

 

[Batmobile_Engage]

I have 272 cams now but not ported heads. Do the cams move the power curve that much?

I would think so. 264 cams would probably support the midrange power you are looking for. Also, a more aggressive cam like a 272 or 280 reduces dynamic compression, which iirc negatively affects the lower end of the powerband in favor of high flow at high rpms. If you want to get the most out of a big cam like that, I think you would want an 8000 rpm rev limit.

Though I might not be totally accurate on that. Let's see what [MENTION=9]HolyCrapItsFast[/MENTION] has to say.

 

[Boogieman98]

I upgraded the valve springs to Supertech and they have upped the Rev limit to 7500. They said no point to go any higher since the turbo drops off around 7000.

 

[Batmobile_Engage]

Hmmm...maybe those cams aren't the best fit then. I hope I'm wrong and you can just have it tuned a little differently.

What's your static compression? 8.2:1?

 

[Boogieman98]

Hmmm...maybe those cams aren't the best fit then. I hope I'm wrong and you can just have it tuned a little differently.

What's your static compression? 8.2:1?

Um I think we stayed as close to stock as possible

 

[Batmobile_Engage]

Any ideas? [MENTION=3416]WRB_STi[/MENTION]

 

[Batmobile_Engage]

This one is pretty decent...

http://www.cyclefish.com/forums/topic/18291/what-you-need-to-know-about-cams

This one is okay too...

http://www.badasscars.com/index.cfm...duct_id=68/category_id=13/mode=prod/prd68.htm

 

[Boogieman98]

Well it appears as though I over cammed

 

[WRB_STi]

Whats your full mod list?

 

[HolyCrapItsFast]

This one is pretty decent...

http://www.cyclefish.com/forums/topic/18291/what-you-need-to-know-about-cams

This one is okay too...

http://www.badasscars.com/index.cfm...duct_id=68/category_id=13/mode=prod/prd68.htm

This is pretty much why I chose to go with the cams that I did. Only a mild 252 duration and a little extra lift is all most applications require especially when you consider the air is forced in. At that point it really doesn't matter what duration you go with unless you are looking for 600whp or more and plan on a 9000rpm motor so you can use your cams to their advantage.

Here is my virtual dyno plot and you can see my power curve is similar to Rick's curve but the torque trumps all by maintaining the same values all the way through red line instead of dropping off significantly. Even though I don't get to full power till the end. I have globs of available torque and it pulls through out the entire run. When the power curve intersects the torque curve, it really gets exciting because I still have all available torque. I still have yet to get an actual dyno plot made but I don't expect it to be very different from this. I achieved this primarily because of component matching and timing strategies for both ignition and AVCS.

In your case Rick, I can site anything from differences in components to timing strategies and/or your choice of cams, so your guess is as good as mine as to why there are such differences. The only thing I can say is everything makes a difference. Because of your cams, I would expect your curve to look much like it does now. The other guy with 280 cams is a very unexpected curve for me.

 

[Boogieman98]

100mm Manely Turbo Tuff Pistons
Manley Pro Series I-Beam Turbo Tuff Connecting Rods
Brian Crower Stage 2 272 Camshafts
Supertech Springs
GrimmSpeed Top Mount Intercooler
GrimmSpeed HiFlow Exhaust Manifold Crosspipe
FP GREEN HTZ for Subaru STi/WRX
IAG Silver CNC Top Feed TGV Deletes
SUBARU TOP FEED 1300CC FUEL INJECTORS
IAG V2 Top Feed Fuel Rails
AEM Fuel Pump 320lph
Perrin TURBO INLET HOSE
Cobb Cold Air w/ Box
Speed Density Conversion
CNT performance 08-14 Subaru WRX / STI Catless Downpipe
SPT Exhaust
Up pipe w/Tial 38mm Waste Gate
Grimmspeed 3 port EBCS
3mm phenolic spacers
Stock Crankshaft

 

[Boogieman98]

Well I guess it is what it is and I will have to live with it. At least I now can tell people what not to do based on my experience.

 

[SudoSTI]

I had an FP Green on my old 06 WRX. I don't have the dyno sheet anymore but it looked similar to the first graph you posted. I had the shortblock built but stayed stock compression and heads. Super fun street turbo. I agree that you went a little large on the cams for that size turbo. All good though, it just means you need a bigger turbo.

 

[Boogieman98]

I had an FP Green on my old 06 WRX. I don't have the dyno sheet anymore but it looked similar to the first graph you posted. I had the shortblock built but stayed stock compression and heads. Super fun street turbo. I agree that you went a little large on the cams for that size turbo. All good though, it just means you need a bigger turbo.

I wonder if E-85 will be better with these cams

 

[SudoSTI]

I wonder if E-85 will be better with these cams

E85 reduces spool time so I wouldn't be surprised to see your torque curve look like the initial graph you posted. What brand of 1300cc injectors are you running? You may be on the verge of maxing those out on E85 though. When I had mine tuned I only had 850cc injectors on pump gas and I ran out of injector. My tuner recommended 1000cc to give me some headroom and squeak out a bit more safe power on pump gas. Had I gone E85 I probably would have needed a 1300cc. FYI mine was also an OG Green (back before the HTZ or even HTA) with I believe a non-ported 7cm housing and IIRC was only a 49 lb/min turbo whereas your HTZ appears to be 61 lb/min so I would imagine you would need more injector to compensate. By needing more injector I mean to get the most out of the turbo. Of course you could tune on your current 1300s on E85 and see where that goes before dropping more coin on bigger injectors. I didn't see an adjustable FPR on that mod list but worst case you could bump up your base fuel pressure to 55psi if your tuner is ok with that to make up for lack of injector.

 

[Boogieman98]

I forgot to list the Aeromotive FPR but I did do that as well. I just upgraded the rails and injector from stock rails and 1000cc injectors. On those 1000cc's I was only at 80% if I remember correctly so these 1300's should give me enough room on E-85 or so I hope. I wonder if I am going to make more power on E-85 with these cams then I would if I didnt have these cams. I guess I will find out as soon as [MENTION=9]HolyCrapItsFast[/MENTION] can tune it.