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Lizard
Joined: 03 Nov 2002
Posts: 9364
Location: Abbotsford BC. Canada
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 Posted: Mon Nov 05, 2007 6:42 am Post subject: |
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the same reason for 4 ITBs when NA, throttle responce and moving the power higher up in the RPM band.
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3 928s, |
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peebles24
Joined: 27 Jul 2007
Posts: 43
Location: Terre Haute, IN
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| Posted: Mon Nov 05, 2007 10:54 am Post subject: |
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| morghen wrote: | | Martijnus wrote: | | What's the advantage of 4 ITB's when you got boost? |
kinda' the same when you've got a big boobed blonde for a girlfriend and as an extra...she can cook ! |
 
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1981 924 Weissach, progressive rate coils, Dansk Polished S/S exhaust, free flow Cat, K&N filter
1991 Toyota FJ80 |
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Peter_in_AU
Joined: 29 Jul 2001
Posts: 2743
Location: Sydney, Australia
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| Posted: Mon Nov 05, 2007 12:30 pm Post subject: |
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and of course we're all eagerly awaiting the how-to
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1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)
Learn to love your multimeter and may the search be with you |
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bass gt
Joined: 02 Dec 2004
Posts: 971
Location: Johannesburg for now!!
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| Posted: Mon Nov 05, 2007 7:27 pm Post subject: |
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| Peter_in_AU wrote: | | and of course we're all eagerly awaiting the how-to |
Peter,
I would have thought the pics were self explanatory!! But here's a quick run down.
1. Get lots of metal
2. Get someone who can work with metal
3. Tell them what you want
4. Come back once they say it's done.
5. Pay the man and take item home.
Voila!! The ideal way of making a proper exhaust manifold.
In all seriousness, after all the discussions concerning manifolds with OOTB et al, i got to thinking. I did some design work, calculations and space evaluations, and worked out the various scenarios.
I then took the car, the turbo and my drawiings to a well known exhaust company who did he rest. I readily admit that i have neither the skill or equipment to make such a thing.
The ITB's are Jenvey items, as are the cast 22.5 degree curves. Although more difficult to engineer, itb's offer much better throttle response and fuel mixing than a single throttle. Look at the Japanese cars for example.
The turbo that i will start with is the GT2560. It is rated for 330bhp max, but it is low and mid range i am really interested in. However, i can easily tailor the turbo now that it is a GT unit, rather than the hybrid i was using.
Boost wise, i plan to run whatever boost is needed to achieve the power requirements of my class. The less boost needed the better. High boost is nothing more than a measure of resriction. I would rather make 250bhp at 7psi than have to boost it to 17 psi.
If any of you guys are in the UK next year, please do come along with Simon and i to a race. They are great days out. Check out the calender for next years events once it is announced, and let us know.
As for now, i am waiting for a ton of parts to come in, such as rods, pumps ect. Then i can start to commence the rebiuld.
I'll keep you posted.
Steve
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Front Wheel Drive is the Devil's work. |
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Martijnus
Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands
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| Posted: Mon Nov 05, 2007 10:14 pm Post subject: |
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| bass gt wrote: | | Peter_in_AU wrote: | | and of course we're all eagerly awaiting the how-to |
Although more difficult to engineer, itb's offer much better throttle response and fuel mixing than a single throttle. Look at the Japanese cars for example.
The turbo that i will start with is the GT2560. It is rated for 330bhp max, but it is low and mid range i am really interested in. |
Nice... glad I have ITB's on my NA  thought it would be easier to go back to stock manifold when I decide to boost my baby, but if I do (probably not) I'll just have to build some nice 4 runner manifold to my itb's
I think you're right on the low/mid range, that was my intention too (short runners aren't going to help me with that). If you want high end power your 8 valves probably won't compete with 16v's... torque kicks ass 
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"Rule: Turbo's make torque, and torque makes fun." (C. Bell)
924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment  |
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jurasT
Joined: 24 Nov 2005
Posts: 22
Location: Lodz, Poland
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| Posted: Tue Nov 13, 2007 5:38 am Post subject: |
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| Why did you actually make the 4-1 exhaust manifold ? It looks quite complicated compared to the manifold used on BAE kits (one pipe). Is it any better than the one in BAE kits ? |
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bass gt
Joined: 02 Dec 2004
Posts: 971
Location: Johannesburg for now!!
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| Posted: Tue Nov 13, 2007 10:50 pm Post subject: |
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Juras,
I've never seen a BAE kit, so i don't have anything to reference against. However, seperate pipes will always be better than a log manifold, but add more complication. As i was going to the trouble and cost of having it made, i might as well get it made to the best it can be.
Steve
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Front Wheel Drive is the Devil's work. |
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