Your overall favorite engine for a Lotus 7 variant.

[MMTX]

Hmmm....the rev limit on the 2.3L is 7500. Hope you have the 2L

 

Curious, what's wrong with 7500 RPM and more torque?

[jimrankin]

Having an S20000 powered 7 I can tell you it's very low maintenance and solid as a rock. On the down side that STUPID V-tec system may be OK for the commuter cars it was designed for but it is a drawback for daily/street type fun in a seven. Keeping the motor up in the V-tec range is OK on track, but you really draw the wrong kind of attention on the street.

If you can find a quad four cheap buy it!!! These were fantastic motors that will really scream and put out the HP. They were installed into cars that were way too heavy for the four cylinder to really work well in. Not enough bottom end off idle torque (kind of like the early Honda S2000) and you know us americans, we want tire smokin' power off the line. They used to have a problem with head gaskets blowing out on the early motors but got that fixed pretty quick. If you "drove" that power plant with the RPM's up it was downright fast.

GM put all of it's American small power plant focus on the V6's as they were better for both touque and the "smooth" idle the four just wasn't ever going to deliver.

[shiva]

SHIVA

DO YOU KNOW what the engine weighs?

 

From what I was able to find on the web:

 

SR20DET - 149 kg 328 lbs (Dry)

 

SR20DET was 216.5kg (Wet) with tranny and everything.

[Croc]

Curious, what's wrong with 7500 RPM and more torque?

 

Absolutely nothing - in fact I am a fan of it. I was more making the observation that Karl was seemingly over-reving his engine based on what Cosworth told me to stick to (for me 7500 for the 2.3L Duratec). The Cosworth 2L Duratec with its shorter stroke is good for 8500.

[MMTX]

What about the Focus SVT Zetec, particularly using the original EFI, harness and ECU, which I have seen used in another built car. It worked really well in that car. An aftermarket piggyback is available to tune it like you would a Haltech.

 

Anyone put one of these in a Seven? If so, I'd love to hear from you. I have a low mile SVT available to me.

 

(Too bad I can't use the 6 speed Getrag transaxle in a Seven. Hey baby, nice box.)

[scannon]

What about the Focus SVT Zetec, particularly using the original EFI, harness and ECU, which I have seen used in another built car. It worked really well in that car. An aftermarket piggyback is available to tune it like you would a Haltech.

 

Anyone put one of these in a Seven? If so, I'd love to hear from you. I have a low mile SVT available to me.

 

(Too bad I can't use the 6 speed Getrag transaxle in a Seven. Hey baby, nice box.)

The STV Focus was the engine of choice for Caterhams until they switched from Zetecs to Duratecs.

 

The first Seven I drove was Caterham USA's (at that time it was called Rocky Mountain Sports Car, Inc) SV demonstrator with an SVT engine with cams, not sure what ECU it had.

 

I have access to a wrecked SVT Focus with 73k miles. If anyone is interested I can sell you the engine with ECU and harness for $850.

[Croc]

What about the Focus SVT Zetec, particularly using the original EFI, harness and ECU, which I have seen used in another built car. It worked really well in that car.

Anyone put one of these in a Seven? If so, I'd love to hear from you. I have a low mile SVT available to me.

 

 

My previous seven had the SVT with the original EFI/ECU and harness. I loved it - very reliable. It was mated to the T-9 5 speed box. Not sure if it was a very large performance improvement over the standard zetec though. There was a post on here by about the trials and tribulations from another car on adding cams, throttle bodies and mapping the engine for best performance.

 

http://usa7s.com/vb/showthread.php?t=1577&highlight=zetec

 

This shows the flat spot that exists in the standard engine around 3000rpm (from memory). In practice I never really noticed this flat spot from my driving experiences.

Edited August 17, 2011 by Croc

[westy turbo]

My Westy is Vaux turbo equiped,which am more than happy with performance and parts available for it,now in US,i quess the duratec is more popular and the parts are easier to get??

[MMTX]

I got to drive an S2K with the 2 liter Honda in it today. I have written previously that the 2 liter Honda S2000 is really a problem because of the lack of good torque below 5000 RPM.

 

However, I have also written on this site a theory that I have had that the same anemic torque band experienced in the 2600 pounds of the S2000 could actually be an advantage in a 1200-1300 pound Seven. The need to control lots of potential wheelspin off the line and in low speed maneuvers with an engine that produces abundant low end torque can certainly make actual performance suffer, or at the least be much harder to control, even though it can also be a lot of fun.

 

Well, I finally got to test that theory today. The results were better than I would have thought, especially with my dismal tests of 2 L (not 2.2L,which is much better) S2000 Roadsters.

 

First, unlike the experience of the 2600 lb S2000 Roadster, you don't have to rev it high to drive around, nor do you have to stuff your foot in it to get it to move. In fact, at lower engine speeds it feels like a normal motor. So you can cruise around without any feeling like you are either lugging it at low engine speeds, nor do you feel like it will have any problem accelerating from low engine speeds. If you want lots of wheelspin it will still easily do it when provoked, but it is very easy to modulate the throttle to get all the usable power to the ground in the straight or in a sharp turn. It will still happily disconnect 245mm wide treaded racing tires if you want to, but the way the power develops in this engine, you have lots of ability to modulate the throttle.

 

I did find that it was not necessary to run it past 5000-6000 RPM to have an enjoyable, spirited drive that would still be faster than most production cars. And, yes, they really do light up about 5000, but I did find that you didn't have to run it past 8000, well below the redline, to even feel the sticky rubber slip at 80 MPH. (BTW, I did do this in a safe place, on a deserted country road.)

 

In a Seven, that motor really does come into its own.

 

As a plus, the transmission ratios feel reasonably well spaced, the shifter is extremely smooth with very short throws, and even more important, the transmission is very strong and durable. In this last regard, I would consider the Honda 6 speed more like the Nissan rear drive boxes, which can handle up to 700 hp.

 

Having driven the 2L in an S2K, it may not be my all time favorite, but it is right up there. We just need to take them all out of S2000's, where they are doing less good. (kidding)

 

Oh, and if you really want all that low end torque, they are supposed to take nicely to superchargers. Lots of torque by 2500 RPM, I was told by the owner of the car I drove that a supercharged version is still very controllable. He also has the SC.

 

BTW, this may be a very nice simple settup, as the S2000 engine uses the stock EFI and computer. Simple (for EFI) and reliable. 240 + reliable HP, dead stock, but w/o such a careful need for delicate throttle control.

 

I really like the Birkins and Caterhams I driven with Zetecs in them, and felt the power in an SC Stalker was copious, and mostly manageable, but this does seem to be one way (of many) to get the best of both worlds.

[jlumba81]

I purchased Croc's Zetec SVT powered 7 and haven't noticed the power dip at 3000 rpm. I'm rarely at WOT (traction issues) so that might be the reason why I haven't noticed it. Its been very reliable. Only mechanical issue I had was my fault. I had a coolant hose rub a pulley. I cut the ziptie holding it in place for some reason and forgot to replace it. Pinhole leak, no big deal. Went to local parts store for hose and coolant. Fixed in 45 mins.

[Onken]

I’ll give you what I drove, what I felt which each car.

I had a Martin Seven, French Seven replica.

The car had the old cast iron 2L Pinto with single Weber carburettor. Giving about 100bhp.

The car was a bit heavy for a Seven with about 700Kg.

The engine was very linear, torque at low rev, not that much power high the rev. The engine was full stock which mean no race so no kick for power, very smooth power curve.

As it was Cast iron engine, it was heavy on the front and I was clearly able to feel it in the steering wheel.

Then I sold it and bought a Caterham 1700BDR.

I was lighter 620/630Kg, had a BDR Cosworth engine.

Same cast iron bottom as a Xflow but revised internal components and the upper part of the engine was alloy with twin cam. That was giving about 170bhp.

The engine was lighter and the car was a lot agile and my old Martin was like a truck compare to the Caterham BDR.

Less torque that the previous 2L pinto, but the car was lighter so still fine. The engine didn’t had a smooth power curve. It was absolutely incredible sound like an Harley Davidson between 1000 and 3000RPM, then kind of transition between 3000 and 4000/4200 RPM. Then from 4200 up to 6500, it was kicking your ass and sound like and old F1 car. Giving you incredible feeling and rising up your arm’s hairs. Here is the BDR engine history:

http://7faq.com/contribute/owbase/ow.asp?Cosworth+BDR+-+it's+history+and+development

To me it was the master piece, the best engine you would ever fit in a Seven.

But I wanted to go on track and the BDR engine is very expensive in case of damage.

I then bought a Caterham C400 with the 2L Duratec engine tune to 220bhp.

That full alloy engine, last generation, lot’s of torque. The chassis is also last generation.

As a result there is nothing to compare to neither the BDR and the Martin. The chassis is very sharp and agile, the car is so easy that you feel very confident. First corner you think bloody hell I fast, and the car is going in the turn very easily and you think I can go at least 10mph quicker and so on. The drawback is very simple to drive far to fast on road but you fill it only when you are coming back to an other car. And that’s dangerous for you and others.

What about the engine, it has to at low rev and lot’s of bhp when revving making it very nice when cruising and enjoyable on far road or track. It sounds fairly nice (not as nice as the BDR but…) and it’s smooth, not very smooth, because when going over 4000rpm it’s kicking a bit until 6000rpm then between 6000 and 8200 rpm it’s becoming scary, thanks to the more aggressive cam.

Here is my opinion according to my specifications:

Light engine (between 80 and 90Kg) to have a light, agile, sharp directions.

No 6 cylinder or 8 cylinders (too heavy) except those from RS Performance

Normally aspired: take less space in the engine bay.

No turbo, due to over heat problem, require exchanger etc

No compressor for the same reasons.

Every body is deferent end has a different feeling, different requirement. You have to make your choice, but it helps if you can try friends car.

If you come to France then send me a MP and we will try to go for a blat.

PS:sorry for my poor English

C U

Onken

[Ruadhd2]

This is great information from someone with experience. Very helpful comparisons. Thank you

[Onken]

This is great information from someone with experience. Very helpful comparisons. Thank you

 

Thanks, I've been driving Seven for 10 years now and I've done about 50 000miles mainly on road.

 

4 cylinders Pinto weights about 135Kg

Zetec 115 kgs

Zetec SE ( all alloy found in the later focus & fiesta & only 1.6 & 1.25) 85 kgs

X Flow is about 110/115Kg

Duratec 2000cc 85 kgs

Vauxhall XE 120 kgs

Rover 1600k series with flywheel, injection gubbins,alternator, coilpack, leads and oil filter is a touch over the 82kg mark

Edited August 23, 2011 by Onken
add an engine weight

[yellowss7]

Rover 1600k series with flywheel, injection gubbins,alternator, coilpack, leads and oil filter is a touch over the 82kg mark

 

:iagree::D:D

 

Tom

[Croc]

:iagree:

 

Tom

 

Wasn't the Rover K engine the one that came with plastic locating dowels for the head as standard? 82kgs is before the driver comes along with his fat wallet for the inevitable head gasket replacements.... unless you do not rev it past 6000rpm.... Oh..hi Tom...fancy meeting you here...:seeya:

[yellowss7]

Wasn't the Rover K engine the one that came with plastic locating dowels for the head as standard? 82kgs is before the driver comes along with his fat wallet for the inevitable head gasket replacements.... unless you do not rev it past 6000rpm.... Oh..hi Tom...fancy meeting you here...:seeya:

 

Yes Mike, the Rover K series did suffer from head gasket issues if you still had the original plastic dowels and if your liner heights were not the required 2-3 thousands above the deck. A good engine builder knows of these issues and they are easily rectified. My red line is 8000 and while I don't get to it in 6th, I don't really need to as I have to slow way down to get by you when you create such big dust storms at NJMP. :smilielol5:

 

The original R500's were Rover Kseries, and they are still considered as quick as the R500 Duratecs. But then again the R500's rev to 8800rpm. Now that's scary. http://www.minister-power.com/ Click on Engines, then MG/Rover and view the different power options. This is the motor that led to the desiganation of SUPERLIGHT. The R500's had a power to weight ratio of 500 HP per Ton. As for you CSR claiming the Superlight moniker...:smilielol5:

 

Tom

Edited August 23, 2011 by yellowss7

[Ruadhd2]

So if one used the car mostly for the road and just one or two track events yearly just to enjoy the experience and not win every event, wouldn't a stock Duratec from a wrecked car work? Could I buy one on ebay from someone with a lot of good feedback offering a decent warranty and have it installed, if I am not concerned with squeeezing every bit of horsepower out of it through modifications? What wrecker would work? What transmission would I mate it with? I'm not mechanical, so I am looking for what to buy to have a skilled mechanic install.

[Kitcat]

Stock Duratec makes abt 140 hp, like a stock Zetec, and way more than an X-flow. Shd be plenty of hp for a se7en, except for the power crazy crowd (like me). Dick Brink told me pays $700 for them.

[Ruadhd2]

Yeah. The one thing you lose when you change out the rotary is hp, Mine puts out about 220. I love the power.

[Croc]

The original R500's were Rover Kseries, and they are still considered as quick as the R500 Duratecs. But then again the R500's rev to 8800rpm. Now that's scary.

 

 

Yes and you had to "refresh" (aka rebuild) the engine every 20,000 miles. That sounds a little too highly strung for me....

 

 

 

As for your CSR claiming the Superlight moniker...

Tom

 

Well, Caterham call it that, its what was on the Manufacturer Certificate of Origin, and it is only slightly short of the 500hp per ton. And it is a definitely a superlight now that it is undergoing some weight shedding and a carbon beauty treatment and dust control measures.