Naturally Aspirated Engine tuning
Discussion
Yes - I am well aware, and well read up on the benefits, costs, ease, etc of supercharging and turbo's. So forget that for a minute.
I'm starting to do a bit of research in this area - there are a few people cottoning on to it now, running either Carbs or Throttle bodies. Anyone on here?
It seems that 150-170 at the fly is not actually too un reasonable to achieve with fuel injected throttle bodies on a 1.8, and can be done on a fair budget.
I have a family member who has run a renowned firm and done great things with K series caterhams, Redtop XE's etc in rally cars, Zetecs etc.
From experience - I love a good normally aspirated engine. not mega power - but thats not what im interested in. A B-road blaster, not a track car. Fantastic throttle response, linear power, free revving, and a great sound would be brilliant.
In terms of tuning - anyone got any good resources? online or books?
Looking at it in pure basic terms, whats the weak points? The Engine seems to be fundamentally a pretty good one for its type, if not brilliant.
The bottom end is good - this is why there so good for FI, correct? But low compression?
Has anyone seen any cars running stroker kits/rebores etc?
Head - this is the main problem I guess. What are the options with regards to later models? Even VVT heads off the very last cars? Can changes be made?
Or sticking with whats given, a good port, polish and rebuild is the way, yes?
Another benefit is addition of very little, if any weight over stock.
I'm thinking aloud. I really want a project to get stuck into, this fascinates me, so any pointers, links, experiences etc would be great.
I'm starting to do a bit of research in this area - there are a few people cottoning on to it now, running either Carbs or Throttle bodies. Anyone on here?
It seems that 150-170 at the fly is not actually too un reasonable to achieve with fuel injected throttle bodies on a 1.8, and can be done on a fair budget.
I have a family member who has run a renowned firm and done great things with K series caterhams, Redtop XE's etc in rally cars, Zetecs etc.
From experience - I love a good normally aspirated engine. not mega power - but thats not what im interested in. A B-road blaster, not a track car. Fantastic throttle response, linear power, free revving, and a great sound would be brilliant.
In terms of tuning - anyone got any good resources? online or books?
Looking at it in pure basic terms, whats the weak points? The Engine seems to be fundamentally a pretty good one for its type, if not brilliant.
The bottom end is good - this is why there so good for FI, correct? But low compression?
Has anyone seen any cars running stroker kits/rebores etc?
Head - this is the main problem I guess. What are the options with regards to later models? Even VVT heads off the very last cars? Can changes be made?
Or sticking with whats given, a good port, polish and rebuild is the way, yes?
Another benefit is addition of very little, if any weight over stock.
I'm thinking aloud. I really want a project to get stuck into, this fascinates me, so any pointers, links, experiences etc would be great.
There is scope to improve the flow of the head. Best to start with a Mk2 head, upgrade the valve train with the FM valves, springs etc. Roger at Sabre Heads (well known in the Lotus world) has done some Mk2 heads (I used to own one) which have seen some good flow improvements.
I think the key to getting more HP is getting the engine to rev higher. MX5Mad.com did a Mk2 with a worked head breathing through TBs and claimed 215bhp. But the bottom end was substantially reworked (billet crank IIRC) and it revved up to about 9,000rpm.
Budget the best part of £10k to get to that sort of BHP figure.
Full details at: http://www.xsspeed.co.uk/natuningirtbs.php
I think the key to getting more HP is getting the engine to rev higher. MX5Mad.com did a Mk2 with a worked head breathing through TBs and claimed 215bhp. But the bottom end was substantially reworked (billet crank IIRC) and it revved up to about 9,000rpm.
Budget the best part of £10k to get to that sort of BHP figure.
Full details at: http://www.xsspeed.co.uk/natuningirtbs.php
FM do a mega 2litre motor with high comp pistons, rods etc capable of a much higher comp ratio. The downside is the cost a roughly $10,000 plus your old engine!
It can be done cheaper, but i'm guessing not by much! Fuji Racing do a good IRTB kit, but they key is in the tuning. Speaking to a bloke at Long Marston who got fed up of trying to tune his to get the throttle repsonse the manufacturer's claim they should give. You need a GOOD aftermarket ECU for this, which don't come cheap for the power gained.
Unshrouding the valves and polishing the heads will give you more, but again, the gains are only small.
NA tuning as you know isn't cost effective. Couple it with some weight savings and you'll be getting somewhere near a decent FI set-up. You won't have much more in the way of torque so losing weight to take adavantage of what you DO have is the key.
Good luck!
It can be done cheaper, but i'm guessing not by much! Fuji Racing do a good IRTB kit, but they key is in the tuning. Speaking to a bloke at Long Marston who got fed up of trying to tune his to get the throttle repsonse the manufacturer's claim they should give. You need a GOOD aftermarket ECU for this, which don't come cheap for the power gained.
Unshrouding the valves and polishing the heads will give you more, but again, the gains are only small.
NA tuning as you know isn't cost effective. Couple it with some weight savings and you'll be getting somewhere near a decent FI set-up. You won't have much more in the way of torque so losing weight to take adavantage of what you DO have is the key.
Good luck!
Good stuff guys, very interesting.
Its totally pie in the sky at the moment, but Its something that does interest me.
A lot of it stems from the fact that I know of friends/others etc who are running Zetecs/K-series etc... Fundamentally similar engines (at the most basic level) that seem to respond very well to tuning - and with the popularity of the Chargers on the Mazda scene it seems to be a bit of a forgotten art.
I wouldnt be looking for building something with headline power - my cars not worth it. If you look at my profile you'll see I've been asking about engine building - I'm looking for something to keep me occupied as much as anything else.
So of course - if your building up from a bare block, you may aswell put the effort in to make some improvements.
Its totally pie in the sky at the moment, but Its something that does interest me.
A lot of it stems from the fact that I know of friends/others etc who are running Zetecs/K-series etc... Fundamentally similar engines (at the most basic level) that seem to respond very well to tuning - and with the popularity of the Chargers on the Mazda scene it seems to be a bit of a forgotten art.
I wouldnt be looking for building something with headline power - my cars not worth it. If you look at my profile you'll see I've been asking about engine building - I'm looking for something to keep me occupied as much as anything else.
So of course - if your building up from a bare block, you may aswell put the effort in to make some improvements.
If you're going to do that, I'd start with stronger components.
Wiseco forged pistons and Carrillo rods are a good place to start. They're also tuned to give better spread of flame and withstand higher loads.
The reason why it is a lost art has already been hinted at. It just isn't cost effective. You can get more power through IRTBs but I believe there is some debate of which type of sock to use to cover them!
As many people just go FI, you may find it hard to get the right kind of guidance.
Wiseco forged pistons and Carrillo rods are a good place to start. They're also tuned to give better spread of flame and withstand higher loads.
The reason why it is a lost art has already been hinted at. It just isn't cost effective. You can get more power through IRTBs but I believe there is some debate of which type of sock to use to cover them!
As many people just go FI, you may find it hard to get the right kind of guidance.
There was a very nice looking 1.6 track car in the classifieds running on carbs apparently to good effect, but I find the whole idea of carburettors archaic. In a previous life I worked as a calibration engineer and electronic fuelling just makes so much more sense: 'I want 'x' milligrams of fuel supplied at 'y' bar pressure at 'z' crank angle.' Ditto with the ignition.
I guess you may be able to save money with some 'bolt on' bike carbs or something off eBay, but make no mistake, suitable EFI will work better.
Sorry, rant over.
I guess you may be able to save money with some 'bolt on' bike carbs or something off eBay, but make no mistake, suitable EFI will work better.
Sorry, rant over.
kevham said:
There is scope to improve the flow of the head. Best to start with a Mk2 head, upgrade the valve train with the FM valves, springs etc. Roger at Sabre Heads (well known in the Lotus world) has done some Mk2 heads (I used to own one) which have seen some good flow improvements.
I think the key to getting more HP is getting the engine to rev higher. MX5Mad.com did a Mk2 with a worked head breathing through TBs and claimed 215bhp. But the bottom end was substantially reworked (billet crank IIRC) and it revved up to about 9,000rpm.
Budget the best part of £10k to get to that sort of BHP figure.
Full details at: http://www.xsspeed.co.uk/natuningirtbs.php
Just found this post through Google as I'm thinking along the same lines as Snotrag.I think the key to getting more HP is getting the engine to rev higher. MX5Mad.com did a Mk2 with a worked head breathing through TBs and claimed 215bhp. But the bottom end was substantially reworked (billet crank IIRC) and it revved up to about 9,000rpm.
Budget the best part of £10k to get to that sort of BHP figure.
Full details at: http://www.xsspeed.co.uk/natuningirtbs.php
However, for £10k why on earth would anyone bother tuning an MX5 instead of buying a mint Honda S2000.
£10,000 to tune an NA engine in this way? You may as well buy an Audi S model with a V8...S8 for example and whack a PES supercharger on it?
http://youtu.be/CVPzgB0LW0Y
http://youtu.be/CVPzgB0LW0Y
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