FW Frog 4x4 Exhaust woes

G

Guest

Guest
Hi Eddie,
Are your cruisers in the UK different to NZ or Japansese one as here the
std system is 2 3/8" with most of the backpressure in the factory triple
pass muffler.
Running a big bore exhaust system will not make horsepower directly but
it will often allow an engine to make power more easily. A std cruiser 2
3/8" exhaust system at full load and relatively high rpm has nearly 5psi
of back pressure which does not hurt power directly but it does increase
crossover pressure between the exhaust manifold and the exhaust system.
By swapping to a 3" system (3 1/2" dump pipes, that bolt on in place of
the stock cast iron outlet, that smoothly taper to 3" outlet are readily
commercially available) backpressure will drop to around 1.5psi which
results in lower EGT's and quicker turbo spool up.
The 1HD-T injectors in stock form are being pushed pretty hard thermally
so pushing up the combustion load without intercooling is courting
injector failure hence piston failure soon there after.
In relation to stainless steel you say you use high quality SS but what
grade is that as 304SS is commonly used because it polish's up nicely
but 409SS is better for durability as it is alloyed with a little
titanium to dramatically improve thermal and vibratory fatigue. Even jig
built stainless can be a pest to fit as it pulls substantially during
welding compared to mild steel. Jig built mandrel bent 2 1/2" mild steel
should be achievable but 3" is likely to require hand fitting and I
think customers are being unreasonable if they don't expect minor
fitting. There is a factory toy system as an option if the want straight
bolt on.
The factory bolts are specials with heat proof self locking nut's.
Cheers,
Craig.
ROBERT SEABORN wrote:
Snip
 
G

Guest

Guest
Craig,
I learn some more, never realised the backpressure would drop so
dramatically. I was aware stainless can move with welding heat but hadn't
thought that would be applicable in this case, I supposed the jig would be
used to weld the exhaust and check accuracy.
(You will have to come over and sort the out - bring tools, I am sure Simon
would be good for the 6000 or so beers to cover the flight.)
Malcolm Bagley
Stafford, UK
1975 FJ45 Pickup (In Work)
_______________________________
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of Craig Vincent
Sent: 28 July 2006 10:14
To: [Email address removed]
Subject: Re: FW: [ELCO] Frog 4x4 Exhaust woes
Hi Eddie,
Are your cruisers in the UK different to NZ or Japansese one as here the
std system is 2 3/8" with most of the backpressure in the factory triple
pass muffler.
Running a big bore exhaust system will not make horsepower directly but
it will often allow an engine to make power more easily. A std cruiser 2
3/8" exhaust system at full load and relatively high rpm has nearly 5psi
of back pressure which does not hurt power directly but it does increase
crossover pressure between the exhaust manifold and the exhaust system.
By swapping to a 3" system (3 1/2" dump pipes, that bolt on in place of
the stock cast iron outlet, that smoothly taper to 3" outlet are readily
commercially available) backpressure will drop to around 1.5psi which
results in lower EGT's and quicker turbo spool up.
The 1HD-T injectors in stock form are being pushed pretty hard thermally
so pushing up the combustion load without intercooling is courting
injector failure hence piston failure soon there after.
In relation to stainless steel you say you use high quality SS but what
grade is that as 304SS is commonly used because it polish's up nicely
but 409SS is better for durability as it is alloyed with a little
titanium to dramatically improve thermal and vibratory fatigue. Even jig
built stainless can be a pest to fit as it pulls substantially during
welding compared to mild steel. Jig built mandrel bent 2 1/2" mild steel
should be achievable but 3" is likely to require hand fitting and I
think customers are being unreasonable if they don't expect minor
fitting. There is a factory toy system as an option if the want straight
bolt on.
The factory bolts are specials with heat proof self locking nut's.
Cheers,
Craig.
ROBERT SEABORN wrote:
Snip

--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.10.4/399 - Release Date: 25/07/2006
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.10.4/399 - Release Date: 25/07/2006
 
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock    No Thanks