What's the difference between 2Ltr, Sprint and V8 ?

[Tamas Petrunin]

Hi,

I've been doing some research and number crunching, I think I can expect 30 to 35 mpg from a 2Ltr or Sprint and around 22 (maybe more with a tail wind) from a V8. So realistically I can drive a 2Ltr 50% further for the same fuel costs of the V8.

So am I better avoiding a V8 and driving more miles each year or will I feel I have settled for second best ?

So how good is the original 2Ltr engined TR7 ?
Is the Sprint really that much better than a 8valver ?
And how much better is a V8 over the other two ?

My heart says get a V8, I've had a V8 in the past and loved the sound and the torque but my head is considering the 2Ltr/Sprint.....

I'm not made of money so what's the best way of getting the most TR7 for my money ?

Should I go and hide now to avoid the flak from asking this question ?

[FI Spyder]

The difference is.....money.

The 2 litre is least expensive, great on twisty roads (a friend said a E-type Jag he was following was surprised he couldn't shake him, pulled away on the straight bits but was caught up on the twisty). Good for cruising on the highway (unless you are going to speed then a V-8 is more relaxed).

The sprint will give more high end performance (higher revs) more like a modern 4 cylinder but a lot more noisy).

A V-8 will have more omph at any speed but you can only go so fast around a corner or so fast on a highway (unless you have money to blow on speeding tickets and it sounds like you haven't).

Fuel mileage is indeed better on the four, it matters little if I use my TR7 or Integra, they get the same fuel mileage even though the Integra has a smaller engine. The difference is the Integra gets it at a higher speed where as the TR7 has a straight line relationship (speed to mileage). You likely won't be using these cars that much any ways so the difference in money spent on gas with a V-8 won't be a whole lot unless you use it as a daily driver and put on a lot of miles.

[Hasbeen]

Firstly, the difference in engine weight between the 4 & the V8 is so small, it has virtually no effect on handling. The 8, well set up will be as quick or quicker in the twisties, if the power is used sensibly. What you do with spring rates, shocks, tyres, & how you work your right foot, will have much more effect on handling than which engine you have in there.

Having said that, with a pretty good 8V, with about 120 BHP & a 4.6L tuned V8 with about 330 BHP, both nicely set up, If I was only allowed one, I would keep the 4 pot. No ball of fire, but my 7 has very good torque making it's 50 to 70 MPH performance very good. It's overtaking in top is excellent. The 8 is magnificent, but 7 is more user friendly.

At these speeds, in the right gear, the 8 is mental. However care is required to avoid spitting the rear end out with throttle at any speed in 1St & 2Nd. Used correctly overtaking is almost unbelievable.

I have done the 1100 kilometres Brisbane to Sydney run in each a couple of times. Cruising at similar speeds, & driving reasonably sensibly, the 7 gives around 8 litres/100 kilometres. This gets up to about 10.5L/100Km in my country town running, & about 12L/100Km when being silly in the twisties. The 8 gave 10.1L/100Km on the same trip, uses about 12.3L/100Km around town, & can actually burn well over 20L/100Km being silly in the twisties. For long trips the cost difference is negligible, & otherwise the small mileage also keeps costs down.

From my observation the cost of building a sprint, or average V8 is very similar. I have had a run in a mates nicely built injected Sprint, up around 140 BHP. It did go well at the top end, probably equal to a stock 8, but lacked the low down torque of my 8V engine. As the sprint requires an extractor exhaust system to fit in there, most have given about 130BHP in mild tune.

Hope this waffle helps.

Hasbeen

[FI Spyder]

From my observation the cost of building a sprint, or average V8 is very similar. I have had a run in a mates nicely built injected Sprint, up around 140 BHP. It did go well at the top end, probably equal to a stock 8, but lacked the low down torque of my 8V engine. As the sprint requires an extractor exhaust system to fit in there, most have given about 130BHP in mild tune.

While no means typical, I have a cautionary tale. A friend (not mechanically inclined so he has his work done professionally) had his 8V upgraded to SU's, tuned headers, SS sports exhaust, K&N air filters. While it rev'd freely above 4,000 rpm, he wasn't satified. He wanted to go the Sprint route. As no Sprints were imported into Canada he got a Sprint head, ready to go from one of the Tr7 specialists in UK. He had the engine machined at a local machine shop that does a lot of our club's engines and assembled by one of our members that was also doing his Dolomite Sprint engine. After being off the road for almost two years waiting for various parts it was finally on the road. He got larger SU's, Vandervell bearings, crank cross drilled, etc. The first couple runs resulted in being towed home as the electronic ignition module kept blowing (I think he went through two or three before he got a good one). It kept stalling out until he sat by the side of the road for a while or got towed (a result of doing away with cannisters and the N/A sealed system). It kept leaking oil, replaced rear main bearing twice until he took it to a members garage and on disassembly found the machine shop left out an oil galley plug at the rear of the engine that was hidden by the rear plate. On his trip back from Portland it conked out just short of the border. He had it hauled back into Canada by Silk Cut Jaguar garage and they found something with the distributor. We went down to Victoria to look at a coupe he wanted to do a V-8 conversion on. Nearing our destination it kept squealing and stalling at idle. Looking at it he said "it only happens when I push in the clutch". It was then I noticed the crank pulley moving, being pushed out of line causing the belt to squeal and the resultant load stalling the engine. After using the clutch as little as possible and dropping me off he said his oil pressure dropped to zero as he got home. Engine toast. Still don't know what's wrong. He covered maybe less than 2,000 Km in four years with almost every trip resulting in problems and/or towing. How much did it cost him? He won't say but we figure at least the price of a really nice TR8 (probably closer to two of them). He's now driving a Jaguar V-8, figuring it'll be a lot cheaper. The TR7 is waiting a few years before he tackles it again.

[Tamas Petrunin]

Thanks for the thoughts so far, keep 'em coming...

The difference is.....money.

The 2 litre is least expensive, great on twisty roads (a friend said a E-type Jag he was following was surprised he couldn't shake him, pulled away on the straight bits but was caught up on the twisty). Good for cruising on the highway (unless you are going to speed then a V-8 is more relaxed).

The sprint will give more high end performance (higher revs) more like a modern 4 cylinder but a lot more noisy).

A V-8 will have more omph at any speed but you can only go so fast around a corner or so fast on a highway (unless you have money to blow on speeding tickets and it sounds like you haven't).

It's good to hear that the 2 litre isn't really lacking, with a 5 speed box it should be okay at motorway speeds (?)

From what you've wrote I'm going to discount the Sprint as an option, I don't particularly like reving a car to the red-line to get the best from it, I prefer to use upto 2/3rds of the rev range and normally like to stick below halfway, also if the Sprint looses bottom end torque over the 2 litre that's a deal breaker for me.

I might not have money to waste on speeding tickets, but then I don't hang about when driving either, and since I live in North Wales where it seems to be that if your not doing the speed limit or a bit more then your holding up everybody else

[FI Spyder]

It gets a bit busy above 60 mph (I have an American car) but you get used to it after a short while and the speed can creep up on you. I have floored it a few times to pass a number of vehicles on the few short straights on #101 in Washington State seeing the needle bounce of the 85 mph peg. Last year going down to Portland I passed a number of cars on a short straight, the last one being a Volvo. Well no Volvo was going to take that from a Triumph so he sped up so he was right behind me. We were soon passing through a few villages with 30 mph speed limits and I thought he might try something foolish like pass me going through these but when we got through them I was able to open it up on the twisty stuff and left him behind. The TR7 Sprint behind me wasn't able to catch up until miles down the road when I pulled off at the off ramp where we were going to have breakfast. Don't know if he never had the chance to pass or was just playing it safe.

[saabfast]

[quote: It's good to hear that the 2 litre isn't really lacking, with a 5 speed box it should be okay at motorway speeds (?)
[/quote]

From memory my 5 speed 2 litre is running at around 3200 rpm at 70 and is fine. Seems to be a good position on the torque band too as its easy to accelerate to 80+ for overtaking when necessary.

[Beans]

Depends a bit on the back axle ratio and tyres fitted.
My DHC with 185/70x13 tyres and 3.45:1 CWP ratio fitted cruises quite happily at 120 km/h @ 3000 rpm.
And the speedo is within 1% of the readings from my GPS ...

[Spectatohead]

But then there is this with a V8. https://www.youtube.com/watch?v=FYkSugCFZX0 My driving style has changed a bit with all of the torque available. No more keeping the revs up all the time. It's weird.

[jeffremj]

I've been doing some research and number crunching, I think I can expect 30 to 35 mpg from a 2Ltr or Sprint and around 22 (maybe more with a tail wind) from a V8. So realistically I can drive a 2Ltr 50% further for the same fuel costs of the V8.

The mileage figures do not match mine for the 16V. I tracked my commute fuel use (60 miles a day round trip, mainly dual carriageways) for a year and this is what I got:

TR7 V8 - 22mpg
TR7 16V - 25mpg

Note that the 16V was the winter car, so that would hit the mpg a bit.

[supercass]

When new the required statutory test figures in the U.K. for a standard 8v gave an urban mileage of 22.7 mpg, 37.9mpg at a steady 56 mph and 30.7mpg at a steady 75 mph. In my experience in everyday use consumption would be nearer the urban figure. (You never drive at a steady 56 as you have to accelerate to that speed and presumably at some stage stop!) 25 mpg thus sounds reasonable. 22mpg for a V8 sounds optimistic to me. supercass

[Sautie]

We don't have many twisty roads but lots of good but straight highways. Some time ago on a 450Km run to Bloemfontein the 7's and sidescreens were amazed to see that the 8's of myself and Marius used less fuel.
The answer I believe is simple it is not speed that uses fuel its revs. Our maximum legal speed on highways is 120Kph and at that my 8 is only pulling 3,000rpm up hill & down hill, while the 7's and sidescreens are probably pulling nearer to 4,000 and may have to change down for the steeper hills.
I am surprised to see that F1 Spider towed his 8, I hope he took the propshaft off. Towing a 7,8 or SD1 is a no no because of the daft lube system when BL converted the 4 box to a 5. In the eighties I had a SD1 that at just over 275,000 faultless Km had graunching noises from the gearbox. It was towed to my usual mechanic (50km away) who when the box was opened found that the gear for the oil pump was almost completely bald. The bearing it lubricates had seized an split the box casing. Moral don't tow because when towing the oil pump doesn't run.

[jeffremj]

22mpg for a V8 sounds optimistic to me

As I mentioned, I got an average of 22mpg over 1 year's worth of commuting - fact, not optimism.

The engine is a 3.5litre, with SUs. It has around 160 bhp and 195 torques. Obviously, something bigger (3.9 +) with more power might not be as economical.

[FI Spyder]

When new the required statutory test figures in the U.K. for a standard 8v gave an urban mileage of 22.7 mpg, 37.9mpg at a steady 56 mph and 30.7mpg at a steady 75 mph. In my experience in everyday use consumption would be nearer the urban figure. (You never drive at a steady 56 as you have to accelerate to that speed and presumably at some stage stop!) 25 mpg thus sounds reasonable. 22mpg for a V8 sounds optimistic to me.

I've only done one mileage calc with my FI TR7 (diff is 3.9). It was from Redding, California to Wilsonville, Oregon. I had just bought it and was driving it home (900 miles). The first part of the trip is through some mountains (1/3) the last part level road. I was restricted to 50 mph because of 55 mph violent shimmy due to bad tires. I pulled off of highway to side towns for breakfast and lunch. At the end of the day I spent some time in Wilsonville, driving around the city looking for a particular store going from memory of a number of years before. When it started to balk due to low fuel I pulled into a gas station to fill up. Doing the calculations the mileage came to 40 point something imperial. So your "required statutory test figures" seem in line. Where I live you don't do "urban driving". The near town is smaller, the two cities on either side is usually driven in on "highways/bypass roads" and "non highway" side roads on the Island are rural twisties (with 36 mph speed limit) which every body goes faster on (2,000 rpm in 5th). If I was driving in Vancouver I have no doubt it would be closer to the 20 mpg figure with it's stop and go and traffic.

[Tamas Petrunin]

22mpg for a V8 sounds optimistic to me. supercass

Many years ago I had a Landrover 110 with the 3.5 Litre V8, now that 4x4 lump weighed 2 ton empty and ran on chunky mud terrain tyres but if I stuck to 50-55 mph on the motorway I could average 22 to the UK gallon.

Of course I had to drive like a tree-hugging save-the-planet eco-mentalist to get that MPG but that 3.5 litre V8 can manage it, So I stuck a gas conversion kit on it because the fuel was under half price and drove it properly and enjoyed the lovely sound of a V8 mind you I still thrashed it from time to time and saw single digit MPG

I think the standard 2 litre engine is the way to go for me, at least that way I can have some fun without always ending up skint, and if I relax a little bit I should easily see 30+ mpg so I can then afford to take it out more often.