HSR Dyno Results
Le Mans Master
Joined: Oct 2007
Posts: 9,700
Likes: 3,469
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
I hear ya! That would bug me too not to be able to take full use of the lightweight parts. I spent more points on suspension so I am only taking 4 points for weight, and I still have the stock hood and glass.
Your power and torque curves are exactly what I am looking for with my new engine!
Your power and torque curves are exactly what I am looking for with my new engine!
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
@Kubs,
Yeah, I ran 275 'Kooks and I still had to add a ton of weight! I spent all that money on lightweight parts, lexan..etc and it just bugs the chit out of me to put ballast in the car. It's nice to mount it low but it still wears out hubs/brakes and tires.
I'm leaning towards putting the large runner setup back on the car and running at 2951lbs (that includes me/gear and fuel after a 40 minute race). 315's on all 4 and that weight should put me back in the 1.7+ G range. I was consistantly 1.53-1.55 with the 275's.
@Greg, You just want your HSR back!
Yeah, I ran 275 'Kooks and I still had to add a ton of weight! I spent all that money on lightweight parts, lexan..etc and it just bugs the chit out of me to put ballast in the car. It's nice to mount it low but it still wears out hubs/brakes and tires.
I'm leaning towards putting the large runner setup back on the car and running at 2951lbs (that includes me/gear and fuel after a 40 minute race). 315's on all 4 and that weight should put me back in the 1.7+ G range. I was consistantly 1.53-1.55 with the 275's.
@Greg, You just want your HSR back!
Interesting that race classes have an intake-installed vs weight rule. So, just by installing your Long-tube intake again, you are allowed to run @ a lighter weight?
Thread Starter
Burning Brakes
Joined: Aug 2005
Posts: 1,172
Likes: 9
From: '88 TPI L98/HotCam Powell, Ohio
It's all hp to weight. If I run my old long tubes it would put me ~330-335 rwhp so I could shed the extra weight. **They don't consider Torque in the equation.
Burning Brakes
Joined: Apr 2006
Posts: 1,218
Likes: 7
From: Burleson Texas
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
No problem...he's right. When I picked/bought my cam, I hadn't decided on a 383 yet. With a TQ setup, it's fine -- even for a 383. With an HSR, I'd probably want more cam -- though I'd try it as-is to see. Or, at least my existing cam in a more-retarded position.
Let's see....was Matt's cam listed here?...
Let's see....was Matt's cam listed here?...
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Because TPIS and AS&M runners are mandrel bent (w/o much wall thickness), you can't really hone/port the length of the runners. You can only port-match the base-runner-plenum transitions.
IIRC, they're in the 1.65 ID range. (I.D.)
For comparison, stock is 1.45, SLP is 1.55 and the FIRST are 1.9" ID. Also, SR tubes are about 1.7".
If you use the standard PI*r*r equation, you'll find there's a significant difference in the cross-section of all these sizes....especially going from stock to a FIRST.
IIRC, it's something like 30% going to the TPIS tubes and 50% going up to the FIRST. People tend to forget circle area grows in a higher proportion to the radius. IOW, even tho radius is only about 30% bigger, the cross-section is more than that.
IIRC, they're in the 1.65 ID range. (I.D.)
For comparison, stock is 1.45, SLP is 1.55 and the FIRST are 1.9" ID. Also, SR tubes are about 1.7".
If you use the standard PI*r*r equation, you'll find there's a significant difference in the cross-section of all these sizes....especially going from stock to a FIRST.
IIRC, it's something like 30% going to the TPIS tubes and 50% going up to the FIRST. People tend to forget circle area grows in a higher proportion to the radius. IOW, even tho radius is only about 30% bigger, the cross-section is more than that.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Yeah...I thought. It's the same cam he used in his last TPI version. For comparison, his TPI dyno was linked (by me) in the L98TPI thread that was up about 2-3wks ago....the one where that guy used AFR heads with a TPIS cam....226/226 duration.
Race Director
Joined: May 2003
Posts: 10,749
Likes: 41
Because TPIS and AS&M runners are mandrel bent (w/o much wall thickness), you can't really hone/port the length of the runners. You can only port-match the base-runner-plenum transitions.
IIRC, they're in the 1.65 ID range. (I.D.)
For comparison, stock is 1.45, SLP is 1.55 and the FIRST are 1.9" ID. Also, SR tubes are about 1.7".
If you use the standard PI*r*r equation, you'll find there's a significant difference in the cross-section of all these sizes....especially going from stock to a FIRST.
IIRC, it's something like 30% going to the TPIS tubes and 50% going up to the FIRST. People tend to forget circle area grows in a higher proportion to the radius. IOW, even tho radius is only about 30% bigger, the cross-section is more than that.
IIRC, they're in the 1.65 ID range. (I.D.)
For comparison, stock is 1.45, SLP is 1.55 and the FIRST are 1.9" ID. Also, SR tubes are about 1.7".
If you use the standard PI*r*r equation, you'll find there's a significant difference in the cross-section of all these sizes....especially going from stock to a FIRST.
IIRC, it's something like 30% going to the TPIS tubes and 50% going up to the FIRST. People tend to forget circle area grows in a higher proportion to the radius. IOW, even tho radius is only about 30% bigger, the cross-section is more than that.
I was referring to the cylinder heads.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
On paper, they flow darn near the same #'s as AFR 180's. (Flow numbers may still be on their website and/or in their catalog. I remember they're nearly identical to the AFR180's). IIRC, their intake runners pour in the 186-188cc range though...meaning they're port velocity is a hair slower than AFR180s...but still very, very good. The main issue choosing between AFR180 and TPIS CNC-porting would be the quality of the original casting. You read some about porter's punching thru walls, but you'd have to think (and TPIS will assure you) that castings are inspected before accepting/porting. Price is, of course, another consideration. If you have good castings and can resell them, the cost of AFR's isn't much more....Plus, you can opt for the 195's or bigger and get something that will outdo even the CNC-ported stuff.
Bottom line: Results I've seen (including Matt's prior TPIS long-tube intake) show the TPIS CNC-ported heads to run as well as they look on paper. TPIS CNC-ported heads should be a valid contender...and this thread supports it.
Of course, the HSR is a good intake too.
Last edited by GREGGPENN; Apr 25, 2012 at 10:37 PM.
