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Pontiac - Boost Turbo, supercharged, Nitrous, EFI & other Power Adders discussed here. |
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#1
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7.2:1 comp ratio, just how much BOOST? Pontiac 400...
Looking for some input here...
The engine: FULLY built 4-bolt main Pontiac 400, 0.030 over bore Nitrited crank Eagle H-beams SpeedPro forged pistons Balanced rotating assembly Heads: 4x, 2.11/1.66, 1H (114cc) Static compression ratio = 7.2:1 What I'm considering is a Whipple / Kenne bell 2.8. This should provide plenty of boost for this application, with some wiggle room to adjust the pressure via pulleys - figuring I could vary from 15 to 25psi. Lastly: I will be using a water-to-air intercooler. I do have a pair of Eaton M-90s that I was going to use, but the Whipple's efficiency is really the right way to go. Thoughts? |
#2
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I had a whipplecharger on a 1991 Mustang 5.0 about 12 years ago. It was a Kenne Bell model. Must say, it really woke up a mostly stock mustang with 6, and then 8 pounds of boost. Much more efficient than the roots type blowers, and response was there from idle all the way up. Some of the other folks here can help you better with the sizing of the whipplecharger you are intending to use here, but what are your overall goals are and where you are going to be using it? Thats the kind of information the guys on this board are going to want to discuss the setup with you. Also, 15-25 psi of boost is sizeable, and you'll want to make sure your head gaskets can hold up to it.
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#3
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Maybe you can use this to give yourself a idea of the boost amount.
(25.58 x 170.866 (blower cubic inch displacement) x blower drive ratio) 400 (engine cubes) x - 14.7 = boost If your planning on running pump gas i would not run more than 11#s of boost with your cr.
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SEVEN UPS 2.0 TAKING THE THIRD DEGREE ONE STEP FURTHER 2016 1/8 MILE 7.0 @ 100 MPH 406 B&M MINI BLOWER |
#4
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It looks like 10psi would be the safest goal... but I did room to grow. I have had a good amount of experience with a manufacturer that was running an intercooled Eaton at 10psi, and IIRC static comp was 9:1 - from the factory. Some guesstimating from that, I assumed that 12-15psi would be achievable w/ 7:1.
Head gaskets: Felpro blues Goals: go as fast as I can. Seriously, I would like to be able to drive it reliably on the street, race it and drive home. Long term: I figured on raising the boost from the 10psi mark with appropriate tuning. FI and IC should keep me pretty safe. I'll come up with a way to monitor detonation. If the head gaskets loose out at the 15psi mark... or if I need MORE, I will step up to Edelbrock heads -- with the option of to bumping the compression to 8.7:1, and the opportunity to o-ring. |
#5
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Jeff,
Sounds like a similar type build to mine. I'm far from an expert here, and just learning myself. But it seems to me that 15 psi on your setup would be a good point to shoot for, but still hang onto some sembleance of reliability. There are people here who will hopefully chime in to give you some input on that specific blower in your application. I think you have to convert your flow in cfm to determine whether the blower is capable of meeting the need for air. |
#6
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Quote:
Thanks for the input. Well, from lerking around, I see that you churned out 800ish at the wheels - so it looks like I'm heading in the right direction! As far as the blower size, that'll be up to Kenne Bell. Their "Mamouth" oughta keep up with whatever I throw at it. Thanks again for the input. |
#7
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Yes, 886 at the rear wheels at 15 psi. 788 hp at 10 psi. But I can't take credit, as Mark built the car, and I have not actually picked it up yet. He is reassembling the ductwork to the turbo after an intercooler change, and then the car will make the 2400 mile trip east on a trailer.
The cam is certainly putting out good power, but with only 1.5 rockers and .520 lift. There is plenty of valve clearance apparently to add 1.65 rockers, so that will be an interesting experiment. Also, those are cast heads flowing around 250, so there is room to improve there as well. I may go to a set of E heads, but there are two repros of RAV heads hopefully being built by people on this forum in the near future, so I'm curious how those will turn out too. What type of manifold are you going to use with the whipplecharger? |
#8
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Manifold: looks like I might go custom. A buddy of mine is fantastic with a TIG, and works for a machine shop, so the base shouldn't be too difficult. Know a source for intake manifold flanges???
I have considered the lower half (or cutting one in half) of a tunnel ram. The Gutsram http://www.wenzlerengineering.com/gutsram.htm is a nice piece, worth every bit of $380... and I could unbolt the carb flanges, and make my IC box to sit on top. It's got the necessary injector bosses, too. My IC will remain a secret at the moment. I'm pretty excited about how it might turn out, and I could possibly make them for resale as well. I'd be interested in hearing more about your set-up (PM or post a link???). |
#9
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How are you going to drive the blower ? Will you be using a serp belt set-up to drive everything or is there a long snout input shaft kit so you can drive the blower alone ? Can you clear a pontiac water pump with a short snout ?
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SEVEN UPS 2.0 TAKING THE THIRD DEGREE ONE STEP FURTHER 2016 1/8 MILE 7.0 @ 100 MPH 406 B&M MINI BLOWER |
#10
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Blower drive - my guess is that the easiest option would be to include it in the serp belt.
Since I'm in the early planning stages of this, time will tell. The only part of the equation that I have right now is the engine. Whipple/KB have plenty of dimensional drawings that I can go off of, so I'll be figuring out where exactly all of this will land. Considering the short snout, I think it would hang way too far fwd if I was to drive it off it's own belt. |
#11
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Since HO 67 Bird is here, why dont you take a look at his thread?
http://forums.maxperformanceinc.com/...d.php?t=621920 If you went the same route he did and cut a plate to mount on top of a donor manifold, you could actually slot holes in the plate slightly for a little front to rear adjustability and just bolt it to the manifold |
#12
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Heh - I was just looking at HO 67 Bird's profile, where he's got pics of his mod'd manifold.
Not worth all the effort for me, since I will be incorporating a water-to-air intercooler in the middle of this mess. I think custom fab will be worth the time spent. It'll give me larger volume plus more room for the IC. |
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