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Buddsy

220 BHP From a N/A?

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Hi all

Just seen this geeza on ebay selling a tunned HC egnine from his excel and says hes got a print out from a rolling road saying it was putting out 220 BHP. Sounds good going can it be reached on a N/A engine? Was just curious.

http://cgi.ebay.co.uk/Lotus-2-2-vegantune-...p3286.m14.l1318

Buddsy


 

"Belief is the enemy of knowing" - Crrow777

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Upgrade today to remove Google ads and support TLF.

Would have thought so yes - the N/A HC unit pushed out about 175BHP I think so would have thought an extra 45 BHP would be achievable by clever tuning/mods............

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You're looking at 100bhp per litre - which has actually been surpassed by standard production normally aspirated car engines (IIRC late 90's M3 was one of the first) - so, yes, I'd have thought very achievable on a carefully prepped engine...

Bikes have been exceeding that since the 80's (OK - I know - at high revs and with relatively low torque...)

Iain

Edited by Iain

"... the Lotus Turbo (Esprit) owner will not only be comfortable in fast company, but will find, more often than not, that he has no company at all!" Road and Track magazine

1983 Turbo Esprit - Silver - 'Lottie' Featured in Classic and Sportscar Aug 2008 and Wheeler Dealers.

1999 Elise - Norfolk Mustard - 'Liz' Daily driver - 221,000 miles and counting!

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I've done a little research on this as I'm changing my engine and wanted to look at options. 220 is fairly easily extractable from it, but it's very top endy to do it without too much low down torque. I believe you can get it up to about 250 before you get serious reliability issues with the internals. Don't forget Lotus didn't want to go higher than 210 because of the Citroen Gearbox, and I'm guessing they wouldn't have wanted the N/A engine putting out as much as the turbo.

Incidentally the same engine as standard in the Excel is rated for 186bhp, but in the Esprit at 180bhp. The difference of 6 is down to the different exhaust systems and runs. If that can make a difference of 6 it's not too difficult to see there's plenty more to be had relatively easily.


Regards

Mat

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Yea was it the Ferrari F40 that was the first 100BHP per litre car?? So I guess it is possible, still good going though.


 

"Belief is the enemy of knowing" - Crrow777

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Hi Buddsy,

go to http://www.lotuseliteparts.bravepages.com/...ce%20heads.html

you can find useful infos about HC modifications.

Reading about that I can say you that such a power are good only for race applications because you need very hot cams that are too hard for road use.

I think that 190 HP are the best you can get for road with still a lot of flexibility and good fuel consumation, it's quite easy to improve a NA engine up to this power with High compression pistons, hot cams (104 on both inlet and exhaust) and ported head.

Cheers

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Filter, gas flowing, exhaust - wouldn't have thought it was a huge problem.

Remember Lotus had to balance a multitude of things to actually sell the car including fuel economy, sound levels (in and out) as well as reliability.

Edited by Jonathan

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Yea was it the Ferrari F40 that was the first 100BHP per litre car?? So I guess it is possible, still good going though.

I'm sure the last F-40 I saw up close had turbo's - so doesn't count! :)


"... the Lotus Turbo (Esprit) owner will not only be comfortable in fast company, but will find, more often than not, that he has no company at all!" Road and Track magazine

1983 Turbo Esprit - Silver - 'Lottie' Featured in Classic and Sportscar Aug 2008 and Wheeler Dealers.

1999 Elise - Norfolk Mustard - 'Liz' Daily driver - 221,000 miles and counting!

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The honda S2000 gets 240bhp from a 2 litre engine, but its is fibre reinforced and has a cleaver cam system. And also it has a brain to mange it all. I'm not sure how reliable an older non ECU engine would be in long term use.


Amateurs built the Ark

Professionals built the Titanic

"I haven't ridden in cars pulled by cows before" "Bullocks, Mr.Belcher" "No, I haven't, honestly"

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I think Mike (the site already shown here)has pushed the Lotus engine further than 220 in NA form.

Using a longer through crank, moved it to 2.5 l and got approx 300HP from it.

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Yep your right Iain it was the F50 i was thinking of 109BHP per litre most powerfull N/A engine of its time.

Giorgio Well im glad a gas flowed my trubo head!! but the owst part in the turbo Esprit engine has to be the exhaust side through that manifold and wastegate looks to be a real bottle neck on the flow!!


 

"Belief is the enemy of knowing" - Crrow777

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Guest bharper

220hp is fairly reasonable from a flowed 2.2 hc, that is not that radical. Probably still stock valve size.

Richard at West Coast Cylinder Heads in California did a head and custom cams for one of the members of jhps.com, oversized valves from a motorcycle, and got 240hp out of it, and is quite driveable. If you go looking in jhps, the name of the Jensen Healey that motor is in is 'Yellow Dog'. Richard at West Coast is the man on this side of the pond for head work, like Dave Smith is in your neighborhood. Kemp is obviously a very gifted lotus engine builder too...

If over 190hp or so need to dowel pin the bottom end on a 907, or go with a 912 or 910 bottom end. The 910 bottom is generally considered able to handle 400hp without problems.

Besides head work, more can be gained by lightening the crank/knife edging the crank. Lighter rods help a bunch too, but can get very expensive very quickly, with titanium being the ultimate, and over $1000 dollars each!

104 intake and 107 exhaust cam is a good combo on a hc engine to retain a lot of torque, and that is the stock cam arrangement in the 912 hc, but if you are running a 2.2L even two 104 cams still has plenty of torque and will not be that bothersome around town. So a simple upgrade of the exhaust cam on a hc will make more ponies...

Dave Smith DS2 cams are considered a little hotter than the 104 cams. He has some other special grinds available too.

A lot has been learned about the 907 series of engines in the close to 30 years of production, and with the older cars not having to meet specific polution specs state side any more, there is a lot of hoping up going on these days. I have a low mile 910 that is probably going back to NA for the S1, with new pistons, some head work and cams, it should easly get over 220hp.....

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A chap here in Norwich who done alot of machining for the Lotus Sunbeam had a son who done grass track motorcycle racing. Well he thought he would make his son a titanium con rod. Well it had its good and bad points. First race, straight out into the lead first bend went straight off and into the crowd!!! lol


 

"Belief is the enemy of knowing" - Crrow777

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Guest bharper

hci turbo was 215-220hp without the charge cooler - with that might add another 10 or 20?? Do keep in mind a turbo has a bunch more torque than a NA....

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