Dissapointing Dyno numbers . . .
Dissapointing Dyno numbers . . . Installed a new TrickFlow cam over the weekend with BTR 7.4 pushrods and PAC 1218 springs. Vehicle Specs:
1981 Volvo 245 DL
2002 5.3l LM7 non-Castech 706 heads BONE STOCK
TF 228/230 .585 112lsa cam
PAC 1218 good to .600 lift
BTR 7.4 hardened pushrods
LS1 Intake Manifold
Hooker Cast Exh. Manifolds (space constriaints)
2.5" Exhaust, X-pipe, dual in single 3" out turbo muffler
T56 w/ LS7 Clutch and flywheel
Ford 8.8, 31 spline trac-lok 3.73 gears
With a custom tune through EFILive car made 305whp/300tq. The base line was with the stock cam and valve springs over a year prior I believe. Made a respectable 250whp/300tq on the stock engine but the sniffer was reading SUPER lean at like 15:1. Ran the car for another 12+ months like that with no issues so I am convinced it was the sniffer and the exhaust leaks that have been fixed.
Looking at the dyno, I just can't wrap my head around the low numbers. It was SUPER hot out and the tuner "heatsoaked" the car as that is the worst condition's it will see. It made sense at the time and I went with it. After driving it, there is room for improvement on the drivability side. While at temp and letting off the throttle, the revs plummet and then surge back to idle. It also seems to hang revs between shifts, which feels strange as to what I am used to out of the car. I know it is cammed but it should be able to return to idle without much fuss. I will say the power delivery is smooth at WOT and it feels plenty faster. Just surprised by the low numbers.
Thoughts on what might be killing power? I know heads and intake aren't helping, but I am down 25whp+ from other dyno sheets I have seen.
1981 Volvo 245 DL
2002 5.3l LM7 non-Castech 706 heads BONE STOCK
TF 228/230 .585 112lsa cam
PAC 1218 good to .600 lift
BTR 7.4 hardened pushrods
LS1 Intake Manifold
Hooker Cast Exh. Manifolds (space constriaints)
2.5" Exhaust, X-pipe, dual in single 3" out turbo muffler
T56 w/ LS7 Clutch and flywheel
Ford 8.8, 31 spline trac-lok 3.73 gears
With a custom tune through EFILive car made 305whp/300tq. The base line was with the stock cam and valve springs over a year prior I believe. Made a respectable 250whp/300tq on the stock engine but the sniffer was reading SUPER lean at like 15:1. Ran the car for another 12+ months like that with no issues so I am convinced it was the sniffer and the exhaust leaks that have been fixed.
Looking at the dyno, I just can't wrap my head around the low numbers. It was SUPER hot out and the tuner "heatsoaked" the car as that is the worst condition's it will see. It made sense at the time and I went with it. After driving it, there is room for improvement on the drivability side. While at temp and letting off the throttle, the revs plummet and then surge back to idle. It also seems to hang revs between shifts, which feels strange as to what I am used to out of the car. I know it is cammed but it should be able to return to idle without much fuss. I will say the power delivery is smooth at WOT and it feels plenty faster. Just surprised by the low numbers.
Thoughts on what might be killing power? I know heads and intake aren't helping, but I am down 25whp+ from other dyno sheets I have seen.
I felt 330whp would be the number as well JakeFusion. Not sure where to even start looking into the drive train. I have driven this thing hard and gone to the track a few times and have had zero issues with the ford axle, trans, and clutch.
The cast manifolds may be hurting you more than anything.
I was just saying the Ford 8.8 could eat more HP than a typical 10-bolt. But the cast manifolds are probably hurting you more.
I was just saying the Ford 8.8 could eat more HP than a typical 10-bolt. But the cast manifolds are probably hurting you more.
Straight from Hooker's website: Recommended for strong performance on engines making up to 500 horsepower (For optimum high rpm performance see Hooker long tube engine swap headers)
I think the Cherry Bomb turbo muffler is a greater restriction than the manifolds.
I think the Cherry Bomb turbo muffler is a greater restriction than the manifolds.
The one dyno in particular that I compared mine against was AGearHead4Life's squirter project. Same cam, truck intake, F-Body manifolds and it still made 326whp. I just can't believe that the hooker manifolds are more of a restriction than F-Body manifolds. He did have the stock heads milled .045 to bump compression but is compression worth that much?
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Truck intake is much better than the ls1 intake.
300rwhp with that cam and exhaust manifolds is actually good IMO. That's a large cam for a 5.3, especially one choked on both intake and exhaust sides.
And yes, milling the heads .045" is a lot and will gain a good bit of compression which in turn gains power.
300rwhp with that cam and exhaust manifolds is actually good IMO. That's a large cam for a 5.3, especially one choked on both intake and exhaust sides.
And yes, milling the heads .045" is a lot and will gain a good bit of compression which in turn gains power.
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Asked the shop for the SAE numbers, they might show another 10whp.
As for the intake, the MAF is on there but not being used, just a 4" 45* bend into a tight 90* bend into the TB. No room for much else.
As for the intake, the MAF is on there but not being used, just a 4" 45* bend into a tight 90* bend into the TB. No room for much else.
What happened here is the cylinder pressure (which kicks the slugs) has plummeted. Stock cranking psi was close to 200 and with the new larger cam it probably struggles to pump 140-150.
The car will be faster when WOT as it picked up 50 horsepower, however it's only in the upper rpms when the small air pump under the heads develops a bunch of piston speed.
The idle and drivability issues seem tune related and not too big of a worry.
I, like others feel the numbers are reflective of your combo....a heavy clutch, low static compression 9.4, stock heads, LS1 intake, and cast iron manifolds....which basically serve to connect the four exhaust ports into one exit and little else !!!!!!
I'd leave the clutch alone as it works well and will serve you for plenty more power.
Like Agearhead4Life you could pop 4.8 flat top pistons in there and/or mill the heads a bunch in order to restore some of the lost cranking pressure and a LS6 intake would be worth 5-7 rear or so but the single biggest improvement to your combo would be headers. Obviously no body makes them for your swap so it would become a visualization exercise to find what will fit and work.....even shorties or mid length would help you 15 rear....long tubes easily 25 or so.
The car will be faster when WOT as it picked up 50 horsepower, however it's only in the upper rpms when the small air pump under the heads develops a bunch of piston speed.
The idle and drivability issues seem tune related and not too big of a worry.
I, like others feel the numbers are reflective of your combo....a heavy clutch, low static compression 9.4, stock heads, LS1 intake, and cast iron manifolds....which basically serve to connect the four exhaust ports into one exit and little else !!!!!!
I'd leave the clutch alone as it works well and will serve you for plenty more power.
Like Agearhead4Life you could pop 4.8 flat top pistons in there and/or mill the heads a bunch in order to restore some of the lost cranking pressure and a LS6 intake would be worth 5-7 rear or so but the single biggest improvement to your combo would be headers. Obviously no body makes them for your swap so it would become a visualization exercise to find what will fit and work.....even shorties or mid length would help you 15 rear....long tubes easily 25 or so.
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From: Coast of San Mateo County Between Pacifica & HMB
I echo everything A.R. Shale Targa has said with one or two additions.
If you have room the FAST LSRXT Truck Intake would probably double
The LS6 intake gains, 10-12 RWHP and give you room to grow down the
Road, Stroker and or bigger bore ( different block obviously) also any thing
That can be done to straighten/ram air in front of the TB would help,
Remove headlight funnel duct, etc( look at Martin from Tic ram air set-up)
Will help a bunch from 45 mph +, and as said before any increase from
.5-1.5 pts of compression along with exhaust improvements will help allot.
You have allot of room and suggestions for improvement, all it takes is
Time and $$$ LOL!, that said it sounds like the car is fun to drive as is
And you have a opportunity to improve steadily along the way!
If you have room the FAST LSRXT Truck Intake would probably double
The LS6 intake gains, 10-12 RWHP and give you room to grow down the
Road, Stroker and or bigger bore ( different block obviously) also any thing
That can be done to straighten/ram air in front of the TB would help,
Remove headlight funnel duct, etc( look at Martin from Tic ram air set-up)
Will help a bunch from 45 mph +, and as said before any increase from
.5-1.5 pts of compression along with exhaust improvements will help allot.
You have allot of room and suggestions for improvement, all it takes is
Time and $$$ LOL!, that said it sounds like the car is fun to drive as is
And you have a opportunity to improve steadily along the way!
Thanks for all of the input everyone! I have a few things to address to free up some more power but after driving the car with some cooler air Saturday night, I think the numbers are just that, numbers. It pulls VERY hard to 6K and gets right back into power after a shift. Runs from 60-120 are pretty quick and it feels strong.
If you need more low-speed power or torque... add a **** ton of timing. You have low compression and still a relatively small cam. If you're not in the mid to upper 30s in the lower speed areas (low RPM and under .40g cyl airmass) of your timing table, then you need to add timing.