3.9L V8 performance/ exhaust mods?

21316 Views 14 Replies 6 Participants Last post by p76rangie, Feb 4, 2010

CSK

Discussion Starter · Feb 3, 2010

Is there anything I can do to give my 1990 Vogue 3.9L V8 auto a bit more boogie?

It seems to run put of breath when overtaking although it rockets up to 100km/hr fairly well.

Currently running on 95 octane, I havn't tried 98 (highest octane we can get in NZ) is it worth it?

I have a set of Pacemaker headers (these http://cgi.ebay.com.au/ws/eBayISAPI.dll ... 0534125261) worth fitting? I'm thinking of getting fitted, but I'm unsure of which size pipes to go? 2.5" 3"? twin tailpipes?

What mods has everyone else done without mentioning dropping in a 4.6L! My 3.9L has only done 175kms/ 109 miles so hopefully I'll see a few more summers out of it yet!

1 - 15 of 15 Posts

classicjack

· #2 · Feb 3, 2010

www.v8 forum.co.uk . Blowers, Webers, headers, tuning, and all that stuff. Also D & D Fabricators, I love their 4 Weber side draft manifold.

p76rangie

· #3 · Feb 3, 2010

Headers will not give it any noticeable power increase and you are basically wasting money. There is no a lot you can do to them except make sure they are tuned and maintained correctly. If you want a bit more power just change over the block to a 4.6.

crypticbcd

· #4 · Feb 3, 2010

p76rangie said:
Headers will not give it any noticeable power increase and you are basically wasting money. There is no a lot you can do to them except make sure they are tuned and maintained correctly. If you want a bit more power just change over the block to a 4.6.

I have to agree with this one. Headers alone will not provide a significant power increase. It may be noticeable, but far from what one might expect for the money spent. You need to keep in mind that exhaust is only one part of the equation. To maximize the results, you need to increase fuel, air intake, and spark as well. Headers often provide a better flow path but without any additional power adders it is hard to benefit from this mod alone. If your OEM manifolds are in good condition, you may want to consider a better muffler and a K&N style filter.

As for the muffler, I spoke directly with Flowmaster regarding this topic. They recommended the Super 50 SUV muffler because of the small block V8 we have. Here are some sound clips (there are many more on the flowmaster website) --

Super 50 SUV series on an F150: http://www.youtube.com/watch?v=qQG8Oo1F27Q

70 Series on a GMC: http://www.youtube.com/watch?v=0h46G-ndBOI

Also, exhaust kits such as NRP, Borla, and MagnaFlow systems cost way too much. You will be better off purchasing items on your own and having a local shop do the install for you.

If you do go with the Hedman Headers, I highly recommend you spend the time stripping the factory paint off (not hard to do) and painting it with some VHT paint. I used this: http://www.jegs.com/p/PJ1/VHT-FlameProo ... 3/10002/-1

I am sure there are other options - but I have used this VHT stuff on both of my Mustangs and had no issues at all.

I am not sure how much money you are looking to spend - but Hedman also offers the same header in a ceramic coat. http://www.jegs.com/i/Hedman/500/39806/10002/-1
Personally, I didnt see it worth the extra cash as these are small block engines with relatively low HP. Just not quite sure that is a wise additional expense.

Let me know if you have any additional questions.

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crypticbcd

· #5 · Feb 3, 2010

p76rangie said:
Headers will not give it any noticeable power increase and you are basically wasting money. There is no a lot you can do to them except make sure they are tuned and maintained correctly. If you want a bit more power just change over the block to a 4.6.

LOL....wait a sec....changing over to the 4.6 is no cheap task. Its definitely a couple steps above some cheap ebay headers though.

leadfoot

· #6 · Feb 3, 2010

I have been reading that the all aluminum buick/rover motor is the premier hotrod motor in the UK, like the chevy smallblock is in the US. It seems you can do alot! I'm still researching myself but I know there are companies in the UK with extensive experience with head porting, cam grinds, and all facets of motor machining. There are companies that sell ECU remapping technology, and ones that sell filters and exhaust setups. The buick/rover motor was designed from the begining as a perfomance platform. Google buick 215 motor mods as well as rover motor hotrods like with the MGB conversion. These people seem to have reliable formulas with predictable returns. I think this motor was designed to rage but was tuned to be a reliable and civil truck motor in the RR.

CSK

Discussion Starter · #7 · Feb 3, 2010

Thanks for the info everyone!

My 3.9L currently has a sticky valve causing an intermittant missfire, by reading other threads in this forum I may have to do the heads, but hopefully the problem goes away.

I do have those headers, I got a unused set 2nd hand for half the price of a new set so if I have to do work on the engine, I'll get them put on.

The 4.6L block sounds good, and I can use the 3.9L heads? I heard those 4.6L blocks get slipped liners etc, so I'm a bit sceptical about putting a 2nd hand block in?

p76rangie

· #8 · Feb 4, 2010

crypticbcd said:
p76rangie said:

Headers will not give it any noticeable power increase and you are basically wasting money. There is no a lot you can do to them except make sure they are tuned and maintained correctly. If you want a bit more power just change over the block to a 4.6.

Click to expand...

LOL....wait a sec....changing over to the 4.6 is no cheap task. Its definitely a couple steps above some cheap ebay headers though.

About $2,000 US for a brand new 4.6 short motor from Land Rover shipped to my home. Headers provide virtually no power increase over the standard exhaust manifold. So yes it is a little more expensive but it will give you a noticeable power increase.

p76rangie

· #9 · Feb 4, 2010

leadfoot said:
I have been reading that the all aluminum buick/rover motor is the premier hotrod motor in the UK, like the chevy smallblock is in the US. It seems you can do alot! I'm still researching myself but I know there are companies in the UK with extensive experience with head porting, cam grinds, and all facets of motor machining. There are companies that sell ECU remapping technology, and ones that sell filters and exhaust setups. The buick/rover motor was designed from the begining as a perfomance platform. Google buick 215 motor mods as well as rover motor hotrods like with the MGB conversion. These people seem to have reliable formulas with predictable returns. I think this motor was designed to rage but was tuned to be a reliable and civil truck motor in the RR.

In the UK these motors were used in many different cars over 30 years from MGs to Range Rovers. Therefore they are as common in the UK as Chev V8's are in the US. It is more this availability that makes them popular rather than them being a performance motor.

p76rangie

· #10 · Feb 4, 2010

CSK said:
The 4.6L block sounds good, and I can use the 3.9L heads? I heard those 4.6L blocks get slipped liners etc, so I'm a bit sceptical about putting a 2nd hand block in?

3.9's also get slipped liner. One in a Disco I purchased had 3 slipped liners. Yes the 3.9 heads and virtually everything else can be used on a 4.6 block.

crypticbcd

· #11 · Feb 4, 2010

p76rangie said:
crypticbcd said:

p76rangie said:

Headers will not give it any noticeable power increase and you are basically wasting money. There is no a lot you can do to them except make sure they are tuned and maintained correctly. If you want a bit more power just change over the block to a 4.6.

Click to expand...

LOL....wait a sec....changing over to the 4.6 is no cheap task. Its definitely a couple steps above some cheap ebay headers though.

Click to expand...

About $2,000 US for a brand new 4.6 short motor from Land Rover shipped to my home. Headers provide virtually no power increase over the standard exhaust manifold. So yes it is a little more expensive but it will give you a noticeable power increase.

Yes, I definitely agree with your comment! But $2,000 is not pocket change to most people.

p76rangie

· #12 · Feb 4, 2010

crypticbcd said:
Yes, I definitely agree with your comment! But $2,000 is not pocket change to most people.

Its about the same price to get top hate liners fitted to an old motor before the cost of new pistons, rings, bearings, etc. Nothing is cheap in Land Rovers, it is just that some options are cheaper than others.

rufant

· #13 · Feb 4, 2010

Ian, do you have a link for the engine supply?

leadfoot

· #14 · Feb 4, 2010

I just discovered RPI engineering. They have everything rover V8

p76rangie

· #15 · Feb 4, 2010

rufant said:
Ian, do you have a link for the engine supply?

They have specials from time to time. About a month ago they had 6 4.6 short motors for $2,300 each delivered.
http://www.landroverclassicparts.com.au/?p=home

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