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EB – best Exhaust size / Diff ratio for EB II

6K views 17 replies 8 participants last post by  defective 
#1 ·
All right, me and a mate have just recently given Holden the dump and picked up a few ford EB II’s. I’m very technically minded and have had a lot of experience with doing up cars and mechanics so chuck it all at me.

Both cars are 4 speed auto’s and will have a stage 3 shift kit put through them shortly, as well as the intakes widened and K&N air filters fitted. Plugs, high flow injectors, leads, fuel pumps and such will all be changed to higher quality setups, but what I’m really interested in is exhaust size and diff ratios.

I’ve done a lot of searching and phoning around on the subjects so I have got a fair idea on what diff ratios tend to work best in the EB’s and what exhaust sizes give the best but I want to get some opinions.

The cars are being worked for performance not soo much as sound, so a quicker take off will far outweigh a low note capable of setting off every car alarm in the neighbourhood.

If anyone has had any experience with diff ratios and exhaust sizes on an EB II then please post below. And please, think constructive. One thing I used to find a lot on Holden forums was people telling me if I want performance get the next model up. I am happy in my decision to work with the EB II and don’t wish to be told to get an XR6 or something like that… Well, maybe you can tell me once, but that’s it... :)


Thanx in advance,
Defective User
 
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#2 ·
Do a search..
But imo copy the latter model E.L's- XR's like more compression,higher fuel pressure, mill or mod inlet maybe shorter runners, better valve springs and cam with higher lift esp. Them I like a low final drive if power is your go and you don't cruse interstate too often like 3.7 f/d or lower.. Similar to latter XR's only 1+ step more.. There seems a restriction in those inlets about 130 rwkw they seem to hit a wall.Ford went vairiable inlet from E.F and they fit but you need some way of making it work, some guys on here have tried/ done just that...
 
#3 ·
3.45 (Xr6 LSD) are a popular choice and would be the best choice for performance vs economy.
Exhausts well they are all over the place.
I've had excellent experiances with the Dynomax/Lukey headers and exhausts but they are the cheaper brand.
Pacemakers are good as well.
Don't worry to much about the cats. The standard Ford Cats are excellent and flow quite well.
Hope that helps dude.
 
#4 ·
for exhaust size I think stock on EBII was 2" maybe 2.25, most people reckon 2.5 is enough for non-forced induction engines, apparently 3" can be a problem if you want to low the car a fair way.

I have pacemakers, no complaints from me but i havent driven any other falcon 6's with extractors so i cant really compare...
 
#6 ·
Walkinshaw said:
i dont think the EA==> ED inlet manafold has a 130rwkw limit on it, seing that its flows better than the dual runner model
Well show me some numbers then where an n/a E.B goes much over 130 rwkw.The latter AU's can quite easy with some small mods..Up top rpm the latter inlets surely can't be beat'n with its short runners...Excluding fabricated inlets..
 
#7 ·
Well sounds as though ripping the guts out of a VL diff and having them wedged in mine, or ripping the rear axel of an XR6 is gona be the way to go. A 3.45 ratio seem to be the one that most people chose, even over 3.7. Funs gona be recalibrating my speedo for it. Praise god for Ford Mods web site.

Working on an EB II is quite a step up from the Holden VK I’ve been tinkering with lately.

As far as exhausts go sounds to me like the standard cats aren’t too bad; crazy’s post wasn’t the only one to confirm that. A 2 1/2” with extractors sounds decent for the EB’s, I’ve heard talk around here that anything above that starts to cut into your performance anyways, so ill see what my mates at Bevic’s Auto can track down for me.
 
#8 ·
Wouldnt go more than 2.5". In a 3" exhaust the gasses cool down to fast (becoming more dense) and therefor more power is needed to puch the gasses out the exhaust.
Learnt this in a physics assignment last year, so school wasnt that much of a waist of time :)


Jase
 
#9 ·
Good to see that physics class actually showed up something useful for someone. Not too say that some of what was taught wasn’t interesting, I just questioned the need to know a great deal of it.

Anyways what you said makes sense. A 3” would not heat up as much because it would have a grater cooling surface area causing the gasses to also lose a lot of there heat. Funny, when it comes to exhausts bigger is not always better. If the gasses are too cold, they would make it harder for the car to push them through then if they were flowing through a well warmed 2 1/2” system where adequate space is allowed for quick removal of them, but cooling area is still kept to a minimum.
 
#10 ·
Thats why i hate lil jap 4cyl cars with 3" zorst thinking that they get a power boost. For hi power cars it needed (more gas to be expelled), but for most its a waist of money.

There is a site somewhere which has 'Exhaust theory' article on it, good read, havent been able to find it for ages but. tells you what to look for.



Jase
 
#11 ·
oh i better mention that there is 'cut offs' for exhaust size, depending on car power.
For example
[MADE UP NUMBERS FOR EXAMPLE ONLY]
upto 170hp no bigger thatn 2".
upto 300hp no more than 2.5" etc, etc.

Most shops probably wont be able to tell you these, but there are sites with that info. If i find a site i'll post it


Jase
 
#12 ·
Ye, a high powered car would also produce the heat needed to get a 3” exhaust up to temperature and in itself would run hotter then most standard engines; so it would push out hotter gasses which in turn would not lose enough heat in a 3” system to cause any problems. That lil 4 cyl engine though would be freezing its balls off…

Well since all the sites I looked up on Exhaust Theory had “exactly” the same info on them ill just post the first one I found (its some good reading)

http://www.nsxprime.com/FAQ/Miscellaneous/exhausttheory.htm

(Geez, haven’t these guys ever heard of Copy Right Laws?)
 
#13 ·
Well since all the sites I looked up on Exhaust Theory had “exactly” the same info on them ill just post the first one I found (its some good reading)
yeah thats the one... i also noticed that about 5 different sites had the exact same article. Theres a couple bits in it that are interesting and relevant.


cheers
Jase
 
#14 ·
use a 2.5inch exhaust and 3.7/3.9 diff ratios.....

Dave.
 
#15 ·
in other threads ive head a the jmm extractors are 1 of the best.

cats -cut off ends and get 2.5" piping welded up.

if u want mainly performance go for the 3.7's, as the first gear in the autos are long.
put on a tranny cooler if it hasnt got one already.

replace the cold air top half with either an xg/xh ute one, i forgot model but will be doin this soon, cheap and easy. as good as the ss inductions one ive heard.
after this resetting of the comp is neccesary.

twin termos of ef/els are a good upgrade, steadier temp., less fan noise and more power(dunno how much though prob around 3/4kw).

advance the timing a touch for premium or the 98ron fuels
 
#16 ·
Damn this is an old thread, very, very old. Was rather surprised to get an email saying someone had posted to it, but oh well.

Since I posted this thread back in mid 2003 I’ve done a few things to the car. One is a full 2 1/2 inch sports exhaust with high flow mufflers and a high flow sports stainless cat. A set of tuned equal length pacemaker headers, EL thermo fans, stage 2 shift kit and a sequential bonnet scoop. Oh ye, and the K&N filter. All up that alone was churning 118.6 rwkw and 683.7 nm. Not bad for an EBII i6 4L. A few other minor mods have been done since, but right now I’m about to remove the head as the gaskets gone and I’m contemplating a few things there too. All and all the car has a noticeable pull and goes fairly well off the line, not to mention a fairly distinct sound, especially when I open her right up. I’ve been told the noise coming from the intake sounds more like a jet engine going off than a car.

Diff is still to be done and will be looking at the EF BBM intake too, just not to sure how to make it work with the scoop yet, may have to get a custom box done for it. Not to mention cam and chip.
 
#17 ·
sounds like its goin good

if your gonna remove the head, consider using an AU head gasket - theyre metal and are thinner than others.

giv us an update on the progress, it would be interesting what kind of 1/4 mile it would do aswell.
 
#18 ·
Re: EB ? best Exhaust size / Diff ratio for EB II

Car’s going very well at the moment. Had to replace the head on it so I took an EF head down to a rebuild shop and had it ported and polished, valves replaced, had the cam shaft re ground and a few other little things. Slight shave and bolted it on with the EF cam and gear. Not going to bother getting a cam setup until I can do the cam and chip at the same time. Still got to get it down to the dyno and have a power run done on her, but its going damn hard.
 
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