Upgrade Heads for 1995 standard 4.0
Upgrade Heads for 1995 standard 4.0
Author
Discussion

lukerogers

Original Poster:

21 posts

142 months

Sunday 13th December 2015
quotequote all
Hi

Looking to get a few extra horses out of the Chimaera. I've had some very good advice so far. At the moment I'm going to change the cam for an MC1, add an ACT induction hose and flared trumpets, and get it chipped and tuned by mark Adams but I am wondering what to do on the heads. I like the look of the V8D stage 3 but it's over my budget if I'm honest. Would I benefit at all from changing the standard heads to ones from the HC engine? Also if I did would this allow me to go for a more aggressive cam such as a stealth?

Any advice is greatly appreciated.

Cheers,

Luke

pwd95

8,457 posts

267 months

Monday 14th December 2015
quotequote all
Upgrading heads, intake & fueling will cost £2-3k & give you 30bhp. Save a bit longer & bolt a turbo on there & enjoy an extra 100+ bhp.....

yes

QBee

22,464 posts

173 months

Monday 14th December 2015
quotequote all
The age old question, and you will get about 100 opinions.

First of all, stop.

Have a very long think about your budget and what you are actually trying to achieve.
And what you want to do with the car.
Then plan accordingly.

You already have one of the best bang for the buck sports cars available in the UK.

Firstly, you can spend thousands of pounds doing the kind of mods you are suggesting and end up with a car that is not really worth any, or much, more than the car with which you started, and which doesn't actually feel much faster. 20-40 bhp improvement - you won't really notice it. If you are merely wishing to have all your pleasure on the public road, sit on your hands and use the saved cash for fuel. Get along to as many car events as you can and enjoy it.

Secondly, the more you meddle with it, I mean modify it, the more you take away from the value, not add to it. Sadly, buyers tend to want a standard car, not a meddled with one.

Thirdly, if you want serious bucket-loads more power that you will really be able to feel every time to drive the car, you have two cost-effective options:

A) Supercharge or turbocharge the car - the 4.0 litre has a nice low compression ratio and is ideal for going forced induction. You will go from your present 210-220 bhp to 330-380 bhp, and will be able to out-accelerate a normally aspirated 500. Cost of the conversion is about £3000, add £2000 for a new ECU to complete the package.

B) Sell it and buy a car that already achieves what you want.

Two years ago I converted a standard 4 litre into a normally aspirated V8D 5 litre, with stealth cam, de-catted, Clive Ford Y, Racing Red dampers, roll hoop, ACT induction, 72mm plenum, bigger injectors, etc etc etc.
The conversion, done a bit at a time, cost me around £10,000. I have 315 bhp and 350 torques.
I now have a car that is exactly how I want it (well, until I decide to turbo it, change the ECU, LS it or whatever).
I love doing track days in it, the torque makes track daying a real pleasure.

But if I had thought through what I was trying to do at the start, I would have sold the car and bought a more suitable one, or would simply have done an LS conversion right from the start.


Don't let me put you off - it's your car to do with as you please - but do it with your realistic hat on.
You are welcome to come and drive mine if it will help.

Dominic TVRetto

1,408 posts

210 months

Monday 14th December 2015
quotequote all
Also remember that the aggressiveness of your cam will be limited by whether you have cut outs in your pistons or not to allow it to run the higher lift/duration without valve-piston contact...

TA14

14,332 posts

287 months

Monday 14th December 2015
quotequote all
QBee said:
The age old question, and you will get about 100 opinions.

First of all, stop.

Have a very long think about your budget and what you are actually trying to achieve.
And what you want to do with the car.
Then plan accordingly.

You already have one of the best bang for the buck sports cars available in the UK.

Firstly, you can spend thousands of pounds doing the kind of mods you are suggesting and end up with a car that is not really worth any, or much, more than the car with which you started, and which doesn't actually feel much faster. 20-40 bhp improvement - you won't really notice it. If you are merely wishing to have all your pleasure on the public road, sit on your hands and use the saved cash for fuel. Get along to as many car events as you can and enjoy it.

Secondly, the more you meddle with it, I mean modify it, the more you take away from the value, not add to it. Sadly, buyers tend to want a standard car, not a meddled with one.

Thirdly, if you want serious bucket-loads more power that you will really be able to feel every time to drive the car, you have two cost-effective options:

A) Supercharge or turbocharge the car - the 4.0 litre has a nice low compression ratio and is ideal for going forced induction. You will go from your present 210-220 bhp to 330-380 bhp, and will be able to out-accelerate a normally aspirated 500. Cost of the conversion is about £3000, add £2000 for a new ECU to complete the package.

B) Sell it and buy a car that already achieves what you want.

Two years ago I converted a standard 4 litre into a normally aspirated V8D 5 litre, with stealth cam, de-catted, Clive Ford Y, Racing Red dampers, roll hoop, ACT induction, 72mm plenum, bigger injectors, etc etc etc.
The conversion, done a bit at a time, cost me around £10,000. I have 315 bhp and 350 torques.
I now have a car that is exactly how I want it (well, until I decide to turbo it, change the ECU, LS it or whatever).
I love doing track days in it, the torque makes track daying a real pleasure.

But if I had thought through what I was trying to do at the start, I would have sold the car and bought a more suitable one, or would simply have done an LS conversion right from the start.


Don't let me put you off - it's your car to do with as you please - but do it with your realistic hat on.
You are welcome to come and drive mine if it will help.
Good post and a great offer.

OleVix

1,438 posts

177 months

Monday 14th December 2015
quotequote all
I was exactly in your shoes 2 years ago. Decided to buy stage 3 heads and a mc1 cam. After I recieved the parts I had done some thinking and I bought a 4.6 block to go with it. And some high comp pistons, and roller rockers, and light flywheel, 45mm intake... new chip and afm, probably spent 4k and got 275hp at crank and 240 at wheels. Great smooth torque curve but not that much faster than my decatted 400!

Now I have ordered the turbo kit and a mega squirt setup, couldve just done that from the start!

TV8

3,526 posts

204 months

Monday 14th December 2015
quotequote all
I would check what the current engine is currently providing and take it from there based on what you actually want from the car. A 400 pulling the power the car should have is as fast as you need on the road in my opinion.

My last car had the full 240bhp on two rolling roads and went very well in day-day use. On track I wanted more and spent double what I sold the old car for to get a 5.3 version. It turned out there was another 2-3 thousand pounds needing spending and now I have spent a lot of money. Ironically, circumstances have meant that I have only used it once on track and it was soaking wet!

N7GTX

8,302 posts

172 months

Monday 14th December 2015
quotequote all
TA14 said:
QBee said:
The age old question, and you will get about 100 opinions.

First of all, stop.

Have a very long think about your budget and what you are actually trying to achieve.
And what you want to do with the car.
Then plan accordingly.

You already have one of the best bang for the buck sports cars available in the UK.

Firstly, you can spend thousands of pounds doing the kind of mods you are suggesting and end up with a car that is not really worth any, or much, more than the car with which you started, and which doesn't actually feel much faster. 20-40 bhp improvement - you won't really notice it. If you are merely wishing to have all your pleasure on the public road, sit on your hands and use the saved cash for fuel. Get along to as many car events as you can and enjoy it.

Secondly, the more you meddle with it, I mean modify it, the more you take away from the value, not add to it. Sadly, buyers tend to want a standard car, not a meddled with one.

Thirdly, if you want serious bucket-loads more power that you will really be able to feel every time to drive the car, you have two cost-effective options:

A) Supercharge or turbocharge the car - the 4.0 litre has a nice low compression ratio and is ideal for going forced induction. You will go from your present 210-220 bhp to 330-380 bhp, and will be able to out-accelerate a normally aspirated 500. Cost of the conversion is about £3000, add £2000 for a new ECU to complete the package.

B) Sell it and buy a car that already achieves what you want.

Two years ago I converted a standard 4 litre into a normally aspirated V8D 5 litre, with stealth cam, de-catted, Clive Ford Y, Racing Red dampers, roll hoop, ACT induction, 72mm plenum, bigger injectors, etc etc etc.
The conversion, done a bit at a time, cost me around £10,000. I have 315 bhp and 350 torques.
I now have a car that is exactly how I want it (well, until I decide to turbo it, change the ECU, LS it or whatever).
I love doing track days in it, the torque makes track daying a real pleasure.

But if I had thought through what I was trying to do at the start, I would have sold the car and bought a more suitable one, or would simply have done an LS conversion right from the start.


Don't let me put you off - it's your car to do with as you please - but do it with your realistic hat on.
You are welcome to come and drive mine if it will help.
Good post and a great offer.
+1 ^^^^^^^^ this is sound advice.

I would just add that bolting on a supercharger or turbo is going to give you almost double the power and more than double the torque but you must have the engine rebuilt first to withstand the additional load.






Sardonicus

19,440 posts

250 months

Monday 14th December 2015
quotequote all
pwd95 said:
Upgrading heads, intake & fueling will cost £2-3k & give you 30bhp. Save a bit longer & bolt a turbo on there & enjoy an extra 100+ bhp.....

yes
yes Pretty much, I also agree with QBee I modded a 4.0 because my time is kinda free and I done my own stuff excluding final machining ..... valve seat cutting, guide reaming, milling etc etc scratchchin it all adds up and my initial cost estimate went up by at least 30% rolleyes but expensive NO cheap definitely NO frown

ChilliWhizz

12,422 posts

190 months

Monday 14th December 2015
quotequote all
Are the 4.6 heads fitted with bigger valves and/or better porting than the 3.9 which (correct me if I'm wrong) the 400 lump is scratchchin I have a set of SD1 heads in my workshop which I bought a few years back for my BGT V8 but never got round to fitting them... just a cheaper alternative to get later/better heads without going to fit bigger valves/porting big ££££ alternative..

Anyway, just a thought...

Dominic TVRetto

1,408 posts

210 months

Tuesday 15th December 2015
quotequote all
Standard 4.6 heads Chilli - no. There are a few sets of 4.6 "HC" heads (of which I had a pair) which incorporate BV's and have seen some valve throat work, but no porting - I managed to get 305bhp out of mine before having to upgrade to worked-over 500 heads

HTH,

Dom