HPR 468 peaking to low.
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Joined: Feb 2018
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From: Lawrenceburg Ky
Is there a 108/112 dbc throttlebody anywhere that you know of. All I can find is dbw.
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https://treperformance.com/i-2390125...y-1750cfm.html
The other is a 115mm I think 🤔💭 let me Search....
The other is a 115mm I think 🤔💭 let me Search....
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Quicker than Expected...bookmarks and Hi... LMAO
https://www.pro-jay.store/products/1...hrottle-bodies
Sorry Moderators...he asked..
https://www.pro-jay.store/products/1...hrottle-bodies
Sorry Moderators...he asked..
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Once you get a time and trap speed You can Eliminate problems by Process of Elimination.
You Got the Size and Parts for Anything needed.
Guy on YB wasn't showing a good ET nor HP number, it was the cam not being dialing in or something along those lines. Didn't really read the thread but did post after the car was showing to be faster.
Get a Good starting Baseline and Document what's Working and Nots working.. process of Elimination.
👍
You Got the Size and Parts for Anything needed.
Guy on YB wasn't showing a good ET nor HP number, it was the cam not being dialing in or something along those lines. Didn't really read the thread but did post after the car was showing to be faster.
Get a Good starting Baseline and Document what's Working and Nots working.. process of Elimination.
👍
You might want to look at your dyno sheet and see if they have a cfm column in there. I think the 102 MM is like a capacity 1170 cfm or so (using the 1.5 inches of vacuum method). So a 105 would be above 1200 cfm.
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The stall won't be an issue really . You only falling off 10 rwhp from 6500 to 7000, it may still like 7500 without to much drop and ride peak power out the whole time. What will tell the tale is how far it falls on the shifts. Then look at converter. Without that data don't touch it
On The Tree
Joined: Mar 2020
Posts: 168
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From: Weatherford TX
My 468 finally made it to the dyno this week and made great numbers and no I won't share them so don't ask. My concern is that it's peaking at only 6500. I was hoping to peak around 7000. Would stepping up to a CID intake and 4500 throttlebody get me where I need to be?
Specs:
HPR 468, 13.5 compression, Tony Mamo Heads 265 heads, hydraulic roller cam 675/.675 lift 262/276 duration 114+4 lobe sep, Carbon PST intake, Holley 105mm throttlebody, 2" headers, E85.
Specs:
HPR 468, 13.5 compression, Tony Mamo Heads 265 heads, hydraulic roller cam 675/.675 lift 262/276 duration 114+4 lobe sep, Carbon PST intake, Holley 105mm throttlebody, 2" headers, E85.
If the lid opening is only 105mm then a new larger TB won't change much for airflow there. The cam seems pretty damn small to me for a drag race 468 to expect more than 6500rpm. Comp spec'ed hydraulic roller was well over 700 lift for a street 468, and I would wager more duration and overlap than your cam too. .74x lift, 26x/27x duration on a 113 +4.
With a powerglide and a good converter it is sometimes faster to shift early and let it ride the converter. Try out what you have. Shift at 6500 as a start. Then shift 7000 and see if it picks up. My experience with some combos is that running out first gear past hp peak sometimes can make near to no difference in ET.
Is the power level on the dyno what you expected? If not then your option is to start changing tons of parts. Otherwise like Summit said you can move the stall down to 5500.
What is your tire height? Have you done the math with your 4.10 gears to see what RPM you'll be at the finish line?
With a powerglide and a good converter it is sometimes faster to shift early and let it ride the converter. Try out what you have. Shift at 6500 as a start. Then shift 7000 and see if it picks up. My experience with some combos is that running out first gear past hp peak sometimes can make near to no difference in ET.
Is the power level on the dyno what you expected? If not then your option is to start changing tons of parts. Otherwise like Summit said you can move the stall down to 5500.
What is your tire height? Have you done the math with your 4.10 gears to see what RPM you'll be at the finish line?
Thread Starter
TECH Regular
Joined: Feb 2018
Posts: 426
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From: Lawrenceburg Ky
Thread Starter
TECH Regular
Joined: Feb 2018
Posts: 426
Likes: 293
From: Lawrenceburg Ky
I had the same valves on my last motor (447) and was turning it 8k.
Last edited by BigDaddy97; Jul 12, 2021 at 01:26 PM.
On The Tree
Joined: Mar 2020
Posts: 168
Likes: 110
From: Weatherford TX
Thread Starter
TECH Regular
Joined: Feb 2018
Posts: 426
Likes: 293
From: Lawrenceburg Ky
I spoke at length with Eric today and he said exactly what I suspected. The carbon pst and 105 throttlebody hits a wall around 6500 on the 468. He reccomended a CID 4.5 with a 4500 throttlebody. He says expect a 50 rwhp gain and several hundred rpm shift in peak. He knows the 468 better than anyone and has studied many dyno sheets. I will go to the track and get a baseline with the current setup before I swap the intake.
On The Tree
Joined: Mar 2020
Posts: 168
Likes: 110
From: Weatherford TX
I spoke at length with Eric today and he said exactly what I suspected. The carbon pst and 105 throttlebody hits a wall around 6500 on the 468. He reccomended a CID 4.5 with a 4500 throttlebody. He says expect a 50 rwhp gain and several hundred rpm shift in peak. He knows the 468 better than anyone and has studied many dyno sheets. I will go to the track and get a baseline with the current setup before I swap the intake.