Your overall favorite engine for a Lotus 7 variant.

[Ruadhd2]

Great car. Great rollover protection. I needed it cause I tried successfully to roll it over. I was 21.

[RossD]

http://www.lotus7register.co.uk/images/l7s1pix/862-01.jpg

 

"SUPERCHARGED FWA COVENTRY CLIMAX - A neat non-Lotus installed Shorrocks Supercharged 1098cc FWA Coventry Climax engine."

From http://www.lotus7register.co.uk/ser1pix.htm

 

Dean,

Thats all I know about it, I give all credit to the UKs register site for the picture and info. I just thought it makes a great desktop picture.

Edited October 26, 2010 by RossD
To add information.

[DeanG]

RossD;

 

What can you tell us about the picture? When was it taken? Details man details!

[MMTX]

OK, I'm going to open this thread back up because I have three engine/transmission combinations I would like comments on and a few questions.

 

First, I would like comments on the Ford 1600 crossflow motors. I've driven one recently, and it is a quaint little thing but 0-60 in a touch under 10 seconds with lots of commotion is a bit slow, which makes me think it is a very stock crossflow. I engine is solid, and seems to have been balanced very well as it revs very smoothly to 8000 rpm. I can't imagine it having more than 80 hp. After all, the car only weighs 1200 pounds.

 

This engine has twin DCOE's, but with the low performance level, it is simple cool looking, but a downdraft would do fine on a motor of that power output. And I don't like DCOE Webbers for driving around town. Best I can tell a 32/36 would be too tall for the hood, and I'm not putting a hole in the hood. Anyway, a Seven that can be blown away by my base Miata just does nothing for me at all.

 

I can already tell that a turbo system can be easily designed that would fit under the hood.

 

From the prices I can find, internally modifying one of these Kent crossflow would be stupidly expensive compared to any other option. And I do have access to buying a turbo system for a Kent.

 

And I want to know who likes these original engines.

 

I would also like to talk with anyone familiar with turbocharging one of these. I am considering the idea of a simple suck through system, probably using an SU or Stromberg side draft as they work well in a simple turbo system, with water/alcohol injection. Low 7-8 PSI boost, 160 - 180 hp goal. Biggest question is I want to keep it simple and reliable, meaning I don't wish to stress the motor too much. And I wonder if stock 9.0-1 CR would be safe?

 

I like the Zetecs and Duratecs, but I have other thoughts.

 

First, one that may seem odd, though my problem is more if it will fit due to transmission size and the deck height of the motor. I have thought of using a Datsun (Nissan) L18 with a suitable 5 speed transmission. The advantages are:

1) Stock motors are balanced to 8000 rpm and already have a very strong forged crank that can handle 400 hp.

2) Due to above, they are easy to turbocharge using a very simple draw through system that can be dialed easily from 180 hp (7-8 PSI) to 325 + hp (15 PSI) without any damage to the stock engine in long life (150,000 + miles) street use. O-ringing the head allows up to 21 PSI safely (well, for the engine), but I wouldn't bother, since even my upper goals for this would only 200 - 225 hp.

3) In this case, I have built turbocharger systems like this for a Datsun 510, so I have parts and knowledge of this system.

4) transmissions are still inexpensive, but more important, extremely strong. (I also still have 4 with the correct gearing.) There are plenty of gear ratio ranges available, but I have been trying to decide if the box is too wide to fit the tunnel.

5) another possible issue with the L series Nissans may be weight as they are certainly heavier than most of the engines typically fitted to Caterhams and Birkins.

 

Then there are the Toyota twincam motors, which look appealing. I know nothing very technical about them, so I do not know which transmission to select, etc. While I can still quote from memory gearing for Nissan rear drive trannies, I know nothing of the Toyotas.

I would also prefer to use a nearly stock ECU and injection system or, if I must use a carb rather than $3500-4000 in aftermarket ECU's and TBI's, I would want to use a down draft carb, as long as it would fit under the hood of a Birkin.

 

I absolutely, positively, have no interest in DCOE's. I really can't stand them. I'm using this as a street car, and have no time to twiddle with tuning carbs. If you love DCOE's please spare me the song about how they are wonderful and easy to tune.

 

Of course a Miata drivetrain and computer could be used and would be somewhat interesting, but does anyone have a Zetec or Duratec using the stock Ford computer and fuel injection system? I am interested more in reliability with reasonable modern power and much less interested in spending another $3000 or more for a custom computer system and throttle bodies.

 

If I could use the stock EFI system, the Duratec would be reasonable, since low mileage inexpensive engines are available and the expensive part is mating to the transmission, so I wonder if anyone has done that.

 

Of course the other option is finding a car I like in or near Texas... I missed the Miata engined one in CA recently because there was no way I will buy anything sight unseen.

[markmad]

In my opinion a 7 must have a 4cyl engine so I would narrow it down to just 4cyl options.

Given this the best and most economical is a Toyota black top 20v Toyota engine

This engine is easily to come by ,has throttle bodies as STD and can be run with the T50 Toyota gearbox .Optional bell housings can be purchased to use it against a Ford/Quaife unit as well. Optional parts are available from Birkin to make the fit easy. Down side is of course it will remain a 1600 and power will realistically always be below 200hp,but in a Birkin this makes for quite a quick race car or even road car.

Duratec is probably the best 2l option, or if you racing any ex touring car engine will do as is the case with many who race 7’s in South Africa.

My personal favourite is Opel/Vauxhall c20xe, has almost 300hp potential as per Duratec though is a little heavier.

Zetec ,nice option but not a engine that will easily give you more than 250hp.But 250hp in a 7 is enough in anycase.

Honda is an option but apparently heavy.

If you really like spending money and like being unique then a Millington Diamond would be a nice buy I guess.

Rotaries are popular in Cape Town because it’s the cheapest way of obtaining 270+ hp. Down side is they heavy, sound like washing machines and if you racing will possibly exclude you from various categories .

Turbos on any engine to make power prove to be more a pain in the rear end in a 7 .

As said this is just an opinion ,but it the above tends to work well more many over here .

[bsimon]

Obviously, I'm a big fan of the C20XE but I wonder if anyone has given any though to the later GM Generation II four cylinder.:Chevy_anim: (not a big Chevy fan, just the first opportunity to use this smiley)

I see 1000BHP blown versions of the Ecotec running on drag strips. Must be a rather strong block and head. I don't know if they breathe properly for NA applications though.

 

Anyone else though about a lightweight oil burner as a prime mover? Maybe a 170 BHP VW/Audi 2.0 TDi, or a 270 BHP 3.0 TDi? Either might be a great candidate for the Stalker chassis as one could fit a large enough gearbox/drive train to contain the torque.

[markmad]

The EXV has been used but it's a far cry from a 20xe .In fact the 20xe's head is still available as new and used for the Spiess formula 3 engines and I believe one of the small European car manufactures will use a rebadged engine in rally cars.

I think when it comes to turbo engines a weak n/a engine can be made to look good quite easily, and yes the blocks casting was increased in thickness as from the C20ex LN onwards to reduce noise hence LN.

[bsimon]

Not the XEV.

I was thinking more in lines of the aluminum block L61 Ecotec with the chain drive cams. Phenomenal HP (800-1000) when blown. I'm pretty sure that none of the Cosworth project KB technology from the C20XE filtered down to the L61 head though.

 

Puffing an engine can certainly make up for ill breathing heads.

[Z3 Stalker]

I believe there is a subaru boxer engined Stalker being built out there in the USA, not sure if it is running yet or not.

[Sabbot]

I guess very few people ever declare that "their baby is ugly" therefore the vote for the good old (very old) kent xflow is largely down to the pragmatism of that's what I have.

On the plus sides

It is easy and relatively inexpensive to build and repair.

It won't set the pavement on fire, but it also means that there is less chance that my modest driving talent outstrips the power available do stupid things with (unfortunately this never a problem while riding sports bikes)

Not that it matters a lot, but next to the A series BMC, it is somewhat historically correct.

With a bit of cursing you can lift it out of the car yourself (if you have to)

A lot of interstate journeys can be a bit boring if you are not constantly listening and waiting for something oily to let loose in spectacular fashion.

You don't need a degree in electrical engineering / computing to tune it.

On the downsides

As driving talent improves a few more horse power would be very nice

Shifting at ~6000rpm seem somewhat pedestrian in comparison to the 12,000+ available from any of the bike derivatives (or even the 9000 redline of honda s2000 lump)

Akin to death & taxes it is a fairly safe bet that it will let go (probably in a spectacular oily manner) at some point in the next few years.

We (have to) laugh in the face of emissions tests...

Other options

My vote would be to follow the Chapman vision of less weight = better performance and combine with a modern bike engine (probably busa-derived).

I don't like turbochargers (never could get used to the lag of mid 80s versions on hot hatches) but I'm curious to see if a supercharger, akin to the units available for B-series MGB lumps could be mated to the xflow to take the usable HP up to around 150ish

[danilo]

turbo kent is just a joke.. been there done that... 30 yrs ago.

Unreliable and fragile

180 hp is Pure Delusion.. 'nuff said.

S2000 car is easily left fer dead buy a Saab 2.0 (let alone the 2.3 version) turbo engine in a Saab 4 door sedan car . Imagine the perf differential in a Seven transplant ...at 1/4 the Honda's wrecker cost... just to add insult to injury.

Sadly the Saab 3 cyl 750cc 2 stroke was 65(?) HP in factory race trim 40/50 'stock', back when it was current. Certainly an Interesting Gizmo but only genuinely competitive against the horrid waste of metal A series engines from BMC.

'Busa engine unit at the typ $3k wrecker price remains as the Best "go fast" choice IMO.. albeit more than a bit frenetic in use, taking some getting used to. But Absolutely thrilling to use.

Test Drive one and see for yourselves ??

[MMTX]

I guess very few people ever declare that "their baby is ugly" therefore the vote for the good old (very old) kent xflow is largely down to the pragmatism of that's what I have.

On the plus sides

It is easy and relatively inexpensive to build and repair.

It won't set the pavement on fire, but it also means that there is less chance that my modest driving talent outstrips the power available do stupid things with (unfortunately this never a problem while riding sports bikes)

Not that it matters a lot, but next to the A series BMC, it is somewhat historically correct.

With a bit of cursing you can lift it out of the car yourself (if you have to)

A lot of interstate journeys can be a bit boring if you are not constantly listening and waiting for something oily to let loose in spectacular fashion.

You don't need a degree in electrical engineering / computing to tune it.

On the downsides

As driving talent improves a few more horse power would be very nice

Shifting at ~6000rpm seem somewhat pedestrian in comparison to the 12,000+ available from any of the bike derivatives (or even the 9000 redline of honda s2000 lump)

Akin to death & taxes it is a fairly safe bet that it will let go (probably in a spectacular oily manner) at some point in the next few years.

We (have to) laugh in the face of emissions tests...

Other options

My vote would be to follow the Chapman vision of less weight = better performance and combine with a modern bike engine (probably busa-derived).

I don't like turbochargers (never could get used to the lag of mid 80s versions on hot hatches) but I'm curious to see if a supercharger, akin to the units available for B-series MGB lumps could be mated to the xflow to take the usable HP up to around 150ish

 

Thanks for the comments on the crossflow. The "waiting for something oily to let loose in spectacular fashion" leaves me with a bit of pause.

 

It also doesn't give me confidence the venerable and quaint old crossflow would be a good candidate for turbocharging. I have already noticed significant differences between it and the Datsun (Nissan) L series engines I have worked with, and the differences don't, as they say, warm my cockles.

 

I personally think the crossflow I have recently driven is a very pleasant car, and it would have been great fun and considered a pretty good performer, 34 years ago, when I first drove one. Now the same performance level seems a bit antique, and there truly is nothing wrong with that if someone is comfortable with that.

 

Unfortunately, I would at least like something that could run close to the turbocharged Datsun 510 that I built in the late 1990's. Before anyone writes there is no comparison, it does take over 200 hp in a Seven and the treaded racing tires to match that 510. The Mazdaspeed Miata I bought after I sold the 510 seemed just pleasant compared to the performance level of that 510, and the Mazdaspeed is no slouch.

 

As to the lag of turbos, there have been a lot of poorly designed turbo systems made, both aftermarket and OEM. Most systems in the 1980's used very low compression pistons which resulted in the NA operation of the engine to be much lower than stock engine. The systems I put in 510's were always able to use the stock compression ratio. And most better OEM systems today use engines that would not feel like you were driving with the brakes on, so this is not such an issue today. If the base engine has pretty good power, a little spoolup is not a bad thing, especially on a light car. It is possible to set up a turbo with virtually no lag, but it isn't easy. As to how desirable this is, I would say it really isn't desirable to have a turbo spool up ultra quick. Turbos result in such a large increase in torque that a smooth spoolup to maximum boost can result in larger amount of power being much more manageable.

 

Having said that, and possibly getting a reaction that that would be bad because it wouldn't launch the car, my 510 with a 1750cc L18 would easily and violently spin the tires in 5th at 60 mph with the clutch engaged (about 2300 rpm), just depressing the throttle about another 1/2 inch when the boost gauge was reading 0 psi. Oh, and that car was also geared for and would do over 160 mph.

 

Even using a turbo, rather than a V8, power still had to be applied with some care to avoid having nothing but wheelspin below 60 mph, and that was in a fairly heavy 510 weighing 2500 pounds with 3.54 gearing.

 

I would think that a turbocharger on an engine of the power level similar to a stock Miata 1.8L could result in very high but manageable and reliable power.

 

A supercharger would work very well. However, the torque could come on rather abruptly though, and while that would appropriate on a heavier car, or a drag car, a smooth onset of power and torque would seem to be perforable. Nothing like getting into trouble in a corner because the blower suddenly shoots another 150 + ft pounds of torque through the drivetrain.

 

A supercharger can be set up to spool up slightly so the power comes on smoothly, so this doesn't have to be a problem. It's all in the design.

 

Still, in my case, I'd be fairly content with 130 hp in a stock engine not having to be run over 6-7k (such as Miata, stock Zetec, Duratec, Datsun L18, etc, etc., etc.) or up to 200hp that doesn't have to be run past 7k. For me the Honda S2000, rotary, or the bike engines are entertaining, but 8-10,000 RPM is just not my personal cup of tea.

 

I like shifting below 6000 if the engine still has a wide torque and power band. I hardly ever took my turboed L18's past 5000 rpm, because they were V8 like from 2000-6200 rpm.

[MMTX]

turbo kent is just a joke.. been there done that... 30 yrs ago.

Unreliable and fragile

180 hp is Pure Delusion.. 'nuff said.

S2000 car is easily left fer dead buy a Saab 2.0 (let alone the 2.3 version) turbo engine in a Saab 4 door sedan car . Imagine the perf differential in a Seven transplant ...at 1/4 the Honda's wrecker cost... just to add insult to injury.

Sadly the Saab 3 cyl 750cc 2 stroke was 65(?) HP in factory race trim 40/50 'stock', back when it was current. Certainly an Interesting Gizmo but only genuinely competitive against the horrid waste of metal A series engines from BMC.

'Busa engine unit at the typ $3k wrecker price remains as the Best "go fast" choice IMO.. albeit more than a bit frenetic in use, taking some getting used to. But Absolutely thrilling to use.

Test Drive one and see for yourselves ??

 

Thanks for the comment on the Kent turbo. I would be curious what was in the Kent, if you remember? (I.E. stock pistons, crank, etc)

 

I did run across a guy with a crossflow in a Morgan, turbocharged to the tune of about 340 hp. But it sounded like he spent about over $10,000 preparing the Kent to be seemingly reliable. Doesn't sound like a realistic alternative.

 

The Saab 2.0 is an interesting thought, but what would you use for a tranny in a Seven? And wouldn't this be as large, or larger than the Datsun?

[shiva]

If I wanted a modern car engine in a modern seven where I was not watching my weight I think the Nissan SR20DET would be a great candidate.

 

Cheers,

 

Dermot.

 

That's actually what I have in my Lotus clone. (The SR27 based on the Deman motorsport design).

 

It's a great engine that has lots of potential. Stock form comes in a 225hp. Mine has been tuned to 300whp@15psi with stock internals. And has still some room for more.

 

I've been driving this car hard on the track for 3 years now. No sign of any engine problems.

 

I love that engine. Other than getting a Hartley V8 or a small LSx engine that's the perfect engine for my use.

Edited August 10, 2011 by shiva

[HOTTTCAR]

SHIVA

DO YOU KNOW what the engine weighs?

[WestTexasS2K]

S2000 with Rotrex supercharger makes massive power and massive torque from 2500-9500. Especially at 23 psi on E85.

 

Not sure how common turbo Saab engines are. I have never seen a Saab i my home town that I'm aware

of. A quick look on eBay revealed a few turbo engines in the 500.00 range. They look rather compact if trans options aren't an issue it would just be a matter of sorting the electrics out. I'm curios what they weigh?

Edited August 11, 2011 by WestTexasS2K

[MMTX]

Not sure how common turbo Saab engines are. I have never seen a Saab i my home town that I'm aware

of. A quick look on eBay revealed a few turbo engines in the 500.00 range. They look rather compact if trans options aren't an issue it would just be a matter of sorting the electrics out. I'm curios what they weigh?

 

I'm curious too. But I'm even more concerned about the transmission problem. After all, Saabs are FWD. Of course finding a good, low mileage Saab might be another problem with this.

 

And low mileage Duratecs are available pretty cheap. The problem is the still using the expensive T9 tranny, bell housing, and of course, the aftermarket EFI. It all adds up.

[WestTexasS2K]

That's one of the reasons I like S2000 drivetrain. It's fast smooth with factory trans and factory ecu. It is rather well engineered too.

[MMTX]

I agree with all the above on the S2000 drivetrain. However, I'm not crazy about motors that have to be run screeching high to get any real torque and power out of them. (Supercharger would completely change this.) The S2000 in stock trim has to be run much higher revs in an S2000 to get going. I remember driving one back in 2001 in comparison to the Miata, the Z3, and the MR2. It was the only one of the three that demanded normal running beyond 5000 rpm. It was annoying to drive normally on the street.

 

I actually compared the S2000 and a base Miata, shifting both at 6500 RPM. I can't remember the exact figures anymore, but the Miata was actually faster than the S2000 when the S2000 wasn't allowed to wrap to over 8000 RPM. It wasn't a fair test, but it was for either one of them in a drag race as both would rev higher, but I wanted to see what the performance was like shifting at somewhat normal RPM's.

 

Further, shifting both cars at 5000 RPM just left the Honda totally useless, while the Miata didn't loose much acceleration at all.

 

With maximum torque of 153 ft pounds at a lofty 7500 RPM, the F20C had nearly useless torque until you wound one past 5000 RPM. The torque band is very peaky. And with maximum power at 8300 RPM with a redline of 9000 RPM, it is running nearly like a bike engine.

 

The fact that the Honda engines have such high piston speeds as they do just screams shorter life. That coupled with the high mileage I've seen in US pulled motors (100-150k) just means it would be best to do an expensive overhaul at the start. The JDM motors usually have far less mileage, but I have never been fond of the JDM motors. I had less than stellar luck with their transmissions. After all, how would you drive a car if the registration and inspection cost was so high that you were going to junk the car in 4-5 years?

 

You'd probably drive the wheels off of it. Especially if it was a sports car.

 

The fact is the F20C put in a Seven certainly makes this a better combination since the lighter weight requires far less torque to launch. It might even be an advantage over the high levels of low end torque in a V6 or LS type V8. After all, if all the torque does is make the back end loose instead allowing a smooth transition of power, it is not going to be as easy to drive in street conditions, nor as pleasant. Having said that, I found a Stalker was easy to drive in street conditions, but you better be gentle with the throttle below 70-80 mph.

 

I actually liked the later 2.2 liter F22C equipped S2000 a lot better. While it still had a bike like peaky torque band, at least the peak dropped to a still lofty 6500 RPM. Plus, it was a much more realistic 8000 RPM motor stock. If I went that route, I would be inclined toward the F22C. But then again, they look to be much less available, and probably much more expensive.

 

This all may be a mute point though since I doubt that Honda's 6 speed will fit in the tunnel of a Birkin or Caterham.

 

Of course this brings us to the Miata drivetrain. It has the advantage of being able to use the stock ECU and harness, seems to fit in Birkin and Caterham cars w/o issue, and produces reasonable power in NA trim, plus there are several moderately priced blowers available to push them safely past 250 hp.

 

I know that I have met with resistance from some Seven people even bringing up the Miata drivetrains. But while I'm not thrilled with Miata drivetrains, it is still a competent engine and transmission that certainly fits within the scope of the Seven concepts.

 

So, any more defined comments about the Miata drivetrains? And does anyone have one of the Westfield cars with the Miata FM settup? Also, and more important for Birkin and Caterhams, does anyone have direct knowledge of one of the cars that has been fitted with one of the Miata motors, including, of course, I'm sure we all hope to here from the new owner in Canada of the California car recently sold.

Edited August 11, 2011 by MMTX
typo

[scannon]

So, any more defined comments about the Miata drivetrains? And does anyone have one of the Westfield cars with the Miata FM settup? Also, and more important for Birkin and Caterhams, does anyone have direct knowledge of one of the cars that has been fitted with one of the Miata motors, including, of course, I'm sure we all hope to here from the new owner in Canada of the California car recently sold.

My Caterham SV has a Miata engine and transmission. AFAIK it is the only Caterham with a Miata engine. I've driven FM's Westfield when it had a normally aspirated 1.6 Miata engine and was very impressed with the performance.

 

I used a 2000 Miata 1.8 engine and transmission in my car. The transmission required removal of about 8 lb of aluminum to make it fit in the Caterham tunnel. Wiring was a challenge because I used an aftermarket Link standalone ECU, a year later converting it to the Hydra Nemesis ECU.

 

http://www.britishv8.org/Other/SkipCannon/SkipCannon-BA.jpg

 

The engine has a Garrett 2560 turbo, intercooler and 550cc RC injectors, otherwise it is completely stock. The latest dyno on it was 301 RWHP and 264 lb ft of torque.

 

It is as easy to drive as a Miata until you go WOT. At that point you had better be pointing straight down the road, one hand on the steering wheel and one on the shifter as you have about 2 seconds in first gear before you shift at 7k rpm. A number of passengers have sworn the front wheels come about 4" off the pavement on the shift to second. I can't verify that because I'm too busy steering and shifting to watch the wheels.

 

Build info is at http://www.cardomain.com/ride/636168/1992-mazda-miata-mx-5/page-10

 

Pictures of the finished car are at the link in my sig line.