loud pipes save lives, and make you go faster too!

john vanlandingham Wrote:
-------------------------------------------------------
> Tom B Wrote:
> --------------------------------------------------
> -----
> > 2.25" you won't need 2.5" until over 200whp
>
> You know those guys we see on videos from Sweden
> and Finland???
> The guys building their motors and exhaust systems
> disagree.
> >
> >
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> John Vanlandingham
> Sleezattle, WA, USA
>
> Vive le Prole-le-ralliat
>
> www.rallyrace.net/jvab
> CALL +1 206 431-9696
> Remember! Pacific Standard Time
> is 3 hours behind Eastern Standard Time.


So what do they say then? Or do they just disagree?

---

Welcome to the cult of JVL drink the koolaid or be banned.

I've used 2 1/2" on 2.0L Ford Pinto motors...
Not the Limas, The EAO 2Ls...

---

SteveL
This is the point in the killing spree when you really should turn the gun on yourself

I have 2.5 inch system on my Rally car, and it is plenty powerful enough. And nice and quiet to boot. Much better for poaching roads on the sly....

phlat65 Wrote:
-------------------------------------------------------
> I have 2.5 inch system on my Rally car, and it is
> plenty powerful enough. And nice and quiet to
> boot. Much better for poaching roads on the
> sly....

Actually 3" 9with mufflers/silences/"boxes" should shift the noise to a lower point on the DB A scale where human hearing is less acute.

Typically on 1600 to 2 liter ROAD cars 2" is "sporty" size, 2 1/2" minimum for rally motors in the milder tune---that is around 175-210 bhp. The more spensive modern fool injectered, and multivalve thangs like the mid 90s F2 cars 'tween 235-265 used 3".


But what the fawk do a bunch Commie alky Square heads, herring chokers and Finns know bout anything, even though I know they dyno the hell outta thing (the top rally exhaust guy in the country is a long term acquaintance) they're so drunk most the time they probably can't focus on the dials, so who care what they say....

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

You can find a bazillion opinions on this. Basically any engine is just a big air pump. Some many cubic feet of air at whatever rpm . The number of bends, length of pipe and type of mufflers used all have a huge effect which can easily negate pipe size. I've seen Mitsus dyno at 400hp and 500 tq with a 34 restrictor and 2 1/2 inch pipe. I've seen Subes post the same numbers with 3".

Also one needs to consider the radius used and the room available for exhaust. There is a rumor in the business that too large of pipe reduces torque.

You can do lots of looking..here's one
http://www.magnaflow.com/07techtips/faq/question10.asp

Modern V-8s manage to put out 3-400 hp quietly from the factory with 2 1/2 or 3" pipe..single on 350 cid.

From what I can see, the "too large" thing seems to apply most to primary pipes, then secondary, and lastly the actual 'under the car bit'.

Some of those modern F2 things, the subset of Group A that free-ed up the restrictive rules that mandated OEM intake and exhaust manifolds and allowed normal headers on ex. and independent throttles on intake side, had some pretty small primaries , around 1.5"/38mm which for a 240-260 bhp motor sounds small, but hey pretty sure they knew what they were doing..

I know that for the commonest motor in Sweden, the Volvo "Redblock" 2300
they have a variety of header sizes.


* Godstjocklek på rören 1,5mm svartstål

Says thickness of material 1,5mm or 060"

* Typ2: Pri44,5 Sek 48 Ut 64 mm-----primary 1.75" sec. 1.88" out 2.5"
Lämplig vid lättare trimning---suitable for light mods

* Typ3: Pri44,5 Sek 51 Ut 64 mm---primary 1.75", sec, 2.0", out 2.5"
Lämplig vid mera trimning---sutable with more mods
Tex rallycross 2150cc---for example 2150 rallycross class.


* Typ4: Pri44,5 Sek 54 Ut 64 mm -----Primary 1.75", sec. 2.125", out, 2.5"
Lämplig vid hårdare trimning---suitable for harder mods
Tex Rallycross 2,4 L Rally ---for example 2400cc rallycross

I am told they all tend to "cone out" over about 19" (0,5m) to 3"

Considering they make at club level in the early 90s about 235 bhp from 2,3 liters and in rallycross just under 290 and those guys are obsessive compulsive about setting things up maybe they know what they're doing...

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Well John all I can say is once again you fail to pay even the slightest bit of attention to the real world here. Timm has a somewhat low spec 1.6 Toyota with cast iron manifold. 2.25 will be fine , 2.50 will work also. I've owned an exhaust shop for over 30 years. Not much I haven't put exhaust on during that time. Lets let the Swedes set this one out.

heymagic Wrote:
-------------------------------------------------------
> Well John all I can say is once again you fail to
> pay even the slightest bit of attention to the
> real world here. Timm has a somewhat low spec 1.6
> Toyota with cast iron manifold. 2.25 will be fine
> , 2.50 will work also. I've owned an exhaust shop
> for over 30 years. Not much I haven't put exhaust
> on during that time. Lets let the Swedes set this
> one out.


I know what he has, we talked over the spec he was building when he was search. he did a good job of searching and the spec should be good, this was more general yakking about sizing.
And ya know, I've been building fairly hottish motors for a few decades too.

Maybe 2.25 is fine, probably.
Onwe thing I like about somewher larger "under the car" parts is there's some area left when it gets hammered, and sometimes stuff does get hammered (specially on cars like mine with NO TUNNEL, yikes!)

More important for him is finding a box with ratios that won't let the nice motor fall flat on its ass every gearchange.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Funny, I thought more important was finally finishing it while its summer so I can actually race the damn car...

---

Welcome to the cult of JVL drink the koolaid or be banned.

john vanlandingham Wrote:
-------------------------------------------------------
> heymagic Wrote:
> --------------------------------------------------
> -----
> > Well John all I can say is once again you
> fail to
> > pay even the slightest bit of attention to
> the
> > real world here. Timm has a somewhat low
> spec 1.6
> > Toyota with cast iron manifold. 2.25 will be
> fine
> > , 2.50 will work also. I've owned an exhaust
> shop
> > for over 30 years. Not much I haven't put
> exhaust
> > on during that time. Lets let the Swedes set
> this
> > one out.
>
>
> I know what he has, we talked over the spec he was
> building when he was search. he did a good job of
> searching and the spec should be good, this was
> more general yakking about sizing.
> And ya know, I've been building fairly hottish
> motors for a few decades too.
>
> Maybe 2.25 is fine, probably.
> Onwe thing I like about somewher larger "under the
> car" parts is there's some area left when it gets
> hammered, and sometimes stuff does get hammered
> (specially on cars like mine with NO TUNNEL,
> yikes!)
>
> More important for him is finding a box with
> ratios that won't let the nice motor fall flat on
> its ass every gearchange.
>
> John Vanlandingham
> Sleezattle, WA, USA
>
> Vive le Prole-le-ralliat
>
> www.rallyrace.net/jvab
> CALL +1 206 431-9696
> Remember! Pacific Standard Time
> is 3 hours behind Eastern Standard Time.


I agree. The problem with exhaust size is A: the actual room to install it. B: The potential for crush as you mentioned. 3: Some of the 3inch pipe is actually thinner and crushes easier.

So either 2.25 or 2.5 as makes sense with a 3inch cat at the back just because.

supposed to work on them in the winter, and play all summer.....

phlat65 Wrote:
-------------------------------------------------------
> supposed to work on them in the winter, and play
> all summer.....


I'm in school, its backwards for me. haha

---

Welcome to the cult of JVL drink the koolaid or be banned.

Dazed_Driver Wrote:
-------------------------------------------------------
> phlat65 Wrote:
> --------------------------------------------------
> -----
> > supposed to work on them in the winter, and
> play
> > all summer.....
>
>
> I'm in school, its backwards for me. haha
>
> Feisty Peacock?
>
>

Most everything is...

Good point. I hang out with people like you...

---

Welcome to the cult of JVL drink the koolaid or be banned.