S1 engine conversion

[CTE]

Does an engine conversion exist for an S1 car which gives a simialr weight balance as the K sries engine, with similar levels of power to a tweaked engine (170hp or so) but is bomb proof?

[Capo]

There is, called a Duratec conversion.

Duratec 2.0 engine with some cams and the rest of the conversion parts will do nicely on horsepower and weight.

[k20erham]

If you want to sound and perform like a tweaked Rover engine then get a Duratec, If you want 220 BHP with 80K doable mileage refinement and a sweet 6peed gearbox to match then only a K20 Honda will do. Try a Honda car before you plump for the Duratec, I am very bias towards the Honda, but you have to spend a lot of money on a duratec to get it anywhere near Honda reliability and performance, and will never sound like a Honda if you like that kind of thing.

[Lefty]

K20 only adds 15kg to an s1 and offers more power and great reliability - and is well proven. For the same money.

I just had mine converted. £3500 for the Stark kit. £1000 for the engine and box, £500 in other parts and 40h labour.

[kambites]

So something like £7k in total for a naturally aspirated K20 installed by someone else, or £5k for a DIY install?

[Lefty]

Yeah but it depends on what else you do. Makes sense to change the clutch while you're in there (£200). Backbox possibly (2bular £600), the stark mid pipe is a slightly large bore than a standard s1 backbox. Hondata is £625 incl mapping.

How far you refresh the engine is obviously a factor. A full rebuild is really expensive on these things. I did all the oils, gaskets, seals, timing chain, tensioner and guides etc.

Edited by Lefty on Thursday 21st July 13:10

[kambites]

Is it really worth refreshing a K20 unless there's actually something wrong with it? They have a reputation for being one of the most reliable engines out there and that's when hauling a car weighing at least 50% more than an Elise. Obviously it's worth doing things like belts while it's out of the car just because it's easier, but anything else seems superfluous.

[Lefty]

I agree but it's getting harder to find lower mileage engines that have been well maintained. I know of two where the oil pump has failed and one where the chain tensioner went.

I'm not talking about new cams/pistons/rods/crank etc mind, that's where the cost can get crazy.

[kambites]

Ho accessible is the Honda lump in situ? Can you do the cam-chain without taking the clam off (access to the belt on a K-series is remarkably good)?

[Lefty]

I think it would a real bd.




Regarding the power delivery, many people have their car mapped on the low cam, then the high cam and move the vtec engagement point to where the two cross. Usually around 4500-5000 rpm. This totally changed the delivery and makes it feel like a totally different engine, you get lots of midrange and same top end but without the big step.

Of course, some will prefer the mad rush of a 6000rpm change. I wouldn't say either is better or worse but am just highlighting that the k20 can be tuned to whatever characteristic you want. I havent mapped mine yet but I think I'll do the former.

Note that it is quite low-geared. 80 in 6th is 4000rpm so still off vtec.

[Motorsport3]

Has anyone ever tried to fit a small Porsche engine (say from the contemporary boxster that was coming w small size too).
That would make a decent Porsche 550 interpretation from the 90s in my opinion.

[Lefty]

Sure it's doable but you'd need to extend the wheelbase for a transaxle gearbox.

Easiest to use something transverse from a front driver.