| There's an article in Revs about head mods, I called the guy at SP performance and although he's never touched a '5 reckons he should be able to get the 115 bhp 1.6 up to around 160 bhp by porting and gas flowing the head, all for the princely sum of about £400, now there's vfm. If you're strapped for cash (as I am) it's got to be a viable alternative to s/c ing. Comments from opposing sides please !! (12/99) |
| Thats a f*****g good bargain!!! Whats his number please????? You get about the same increase from s/charging and that costs £2.5k I wonder if it is actually true... (12/99) |
| Sounds VERY interesting can you keep the list informed if you decide to go this route, Im surprised it would yield an extra 45 hp. (12/99) |
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I'd say it's possible although I'd guess it would need some high lift cams and overbored pistons as well. And this figure is probably with breathing alterations as well (exhaust and intake). And all that won't come to £400. More like a grand (at least). Performance handbook gives a 10bhp figure for gas flowing. CAI and decent exhaust/timing advance can give 20bhp. Can't quite remember figures for cams and piston alterations. Also, what does 'porting' actually mean? (12/99) |
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I would not trust a shop that makes claims like that without ever having seen a head of a 5. From what I know, it actually flows pretty well in stock form, and thus gains are not as high as with some other cars that have rather crappy heads. Keep in mind that this is heresay, as the inside of my engine and head is still untouched. People have gotten as high as 200 hp with N/A cars, but that requires LOADS of cash to be thrown at the engine. I would guess that headwork (port and polish, maybe a little higher compression) might yield 10-15 extra hp, thus making it a not very cost effective mod compared to strapping a charger on. (12/99) |
| Nope, that's just with head mods. Cost for new cams, valves, springs etc is 1950 BUT that's to full race spec and should get you over 200 bhp. As he said, he's never done a '5 before but he's got 240 bhp from the 1.8 MGF engine so he's pretty confident. He'd never done a Ferrari 355 before either, but he got another 100 bhp out of that just by Porting & gas flowing. Amazing but it's all in the mag, whether it's true or not is another question. Hopefully I will be able to find out if I can get some work ! (12/99) |
| I'll be right behind you if you go ahead with this and get the figures he's claiming, but I don't believe this figure he gives for the Ferrari. Surely a Ferrari's engine is tuned to the max to start with and isn't so badly cast that porting and flowing the head would realise a further 100bhp? (12/99) |
| Remember we are talking about more cylinders here. A small increase for each can add up too a lot. Probably won't last long though- which is why it's not like that in the first place. (12/99) |
| I'd recommend a perusal of this site before you spend ££££'s on mods! http://members.aol.com/solomiata//CheapHP.html (12/99) |
| The article is in Jans edition of Revs, but as it takes a while for the pigeon to fly that far north ;-), I'll extract: Peter Fisher at SP Performance, tel 01564 782531. "8 valve engines eg Golf GTI, 20 bhp increase for straight head work 300, fully modified head, new cams & lifters 180 bhp 850." 16v engines eg Elise, no problem 100 bhp/litre 160 bhp MX5, 400. Full race spec 240 bhp, 1950. Work takes approx 1 week, this is valid for any mass produced car as the head is only machined on it's landing faces after casting." (12/99) |
| I dug deep and acquired said mag Revs in the interest of research and all that.. .. the article says some of the right things but also really says 20hp and 15 ftlbs ... which is nearer real life .. and those figures are based on '80 Ford junk with rough casting etc I suspect. .. cross section shown of inlet port ... labelled spark plug hole as injector hole! .. this was also quite brutal porting as he had removed the bottom 1/3 of the valve guide that projects into the air flow, taken the diameter of this area of the valve stem down .. and skimmed both sides of the valve head ... OK for N/A perhaps but questionable for F/I because of the additional heat loading... and valve guide life must be 50% of original.. (12/99) |
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Talked to the man; Peter Fisher of SP Performance Special prices at the moment (i.e. get your attention) ... but real prices are; Gas flow/port 650 GBP Gas flow/port with bigger inlet valves 1000 GBP (Clubman spec) .. should be 1700 ... very interesting chat with him for 30 minutes (don't know how he makes money if he spends all the time on the 'phone .. he did ask if I was calling after the article ... must get 10 a day!!), He is into high flow at low vacuum levels which occurs at low rpm and also every stroke at TDC ... good idea. His heads are winning heaps of stuff at the moment (according to him :-) ) with a figure of 300 hp from 14.5psi boost seen as easy stuff.... he guessed at me making 180 hp at the moment (cw 210 rwhp on a particular Sun rolling road or 235 US dynojet). 4 weeks delivery in real time (i.e. not 'lets be silly and unrealistic') ... now I have this spare cylinder head and inlet manifold ... do I send them or not ... really want to find some other real number gas flow people first .. and 1k is a lot ... but it depends if you want it tickled any old way by a bloke who has never seen a flow bench or an empirical gas flow tested result with a winning pedigree ... he even spouted Bernoulli at me! (19th century Italian gas flow scientist). (12/99) |
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Nice to see all the interest in forced induction. Don't forget about some of the accessories that you will need
sooner or later: These are some nice to haves: Critical items (well, for me at least): |