71 GT-6 w 215 V8

[wrenchmaster]

I just purchased a 1971 GT6 with a 215 V8 and a BW 5spd. Does anyone know what kind of mods can be made to these engines and what kind of HP numbers can be reached?

[Moderator]

Welcome to BritishV8, Charles.

200hp at the wheels is fairly straightforward with simple bolt-on mods. With more radical work (i.e. stroking, forced induction, etc.) the sky is the limit. Remember, your little aluminum V8 has a huge racing heritage: Dan Gurney drove one in the Indy 500 and Jack Brabham used one to win a Grand Prix championship! Your question is one of the main topics of this website. Have a look through our huge article archive (under the left-most pull-down menu at the top of this page) for articles on topics such as camshafts, fuel injection, superchargers, header selection, alternate intake manifolds and carbs, boring and stroking, etc., etc., etc.  You'll also want to check out the MGB GT V8 racecar articles on our sister website, BritishRacecar.com. And then there's the "Drivetrain" section of our message board.

Perhaps this snapshot will give you some inspiration:

[TR4AIRS]

That is one awesome engine bay!

[wrenchmaster]

Thanks for the INSPIRATION! I will get some pics posted as soon as I can. Looking forward fun years ahead with this car.

[triumphtr2]

Curtis. That has to be one of the great pictures of all time. Whose car is that? wow Tim

[BlownMGB-V8]

That is Bill Jacobson's car. A very nice build and he runs a Megasquirt-3 system on it.

Jim

[Bugeyev8]

Ha  Ha 200 Hp at the wheels! we have 4 cylinders at the shop that put 440 rwhp !

[BlownMGB-V8]

Lovely. I saw a '56 Chevy that had a Merlin engine installed in it.

Jim

[roverman]

Hey waitaminuite, I have Merlin heads for a Rover !  Figure/figure.... about 9,000 HP-right ??

[Moderator]

Ha Ha 200 Hp at the wheels! we have 4 cylinders at the shop that put 440 rwhp !

With forced induction.

[V8WEDG]

Quote:
Ha Ha 200 Hp at the wheels! we have 4 cylinders at the shop that put 440 rwhp !

With forced induction.
 


Not to mention Hp is only half the story.
V8s generally have much more low end torque and overall area under their torque curves than 4 bangers.
When I dyno'd my mostly stock TR8, I did it at a Miata club dyno day.
despite upgraded carbs, exhaust, and bumped timing, I barely eeked out 100whp.
There were plenty of turbo Miatas there putting down WAY more than that.
However, every single Miata guy there was green with envy when they saw my torque curve, it practically jumped past 100ft/lb as soon as I hit the gas and stayed above 100ft/lb across the entire usable rpm range:

show me a 100whp 4 cylinder with this much low end torque and overall area under the torque curve!

[Bugeyev8]

honda s2k

[V8WEDG]

S2000? Area under the entire torque curve MAYBE since it revs so high, but low end torque? NO WAY.
First of all, no S2000 dyno graph even goes below 2k, prob because they would stall out below that. My TR8 was spinning the rollers at idle with no gas at all, meaning much more torque at idle.
Second, peak torque on an S2000 doesn't even occur until the VTEC kicks in at high rpm, and is still less than the TR8. Below VTEC it stays between 100-120ft/lbs. My TR8 developed peak torque of 155ft/lbs @ 3k and was above 125ft/lbs from 1200-4200 rpm. That is numerically higher at every point on the graph below 4200 rpm AND the graph extends lower than any S2000 graph.
Third, I see you have a TR8 as well, have you ever driven an S2000? I have, and it's no contest. The TR8 wipes the floor with the S2000 in the torque department.

oh, and I almost forgot, the S2000 is not a 100whp 4 cylinder, it's amost twice that! and still looses the torque battle!

[Bugeyev8]

s2k

[V8WEDG]

You are trying to compare apples to oranges.

1) comparing a highly modified engine (boosted S2K) to an almost stock engine (my Rover V8) [in my response to your original suggestion of an S2K, I was comparing my engine with stock S2K engine dyno graphs]

2) comparing a boosted engine to a naturally aspirated engine

3) comparing a 491WHP engine to a 100 WHP engine when I specifically said in my original post "show me a 100whp 4 cylinder with this much low end torque and overall area under the torque curve"

No one here is arguing that you can't get huge power numbers from boosted engines of any type/size. There have been plenty of boosted Buick/Pontiac/Oldsmobile/Rover V8s over the years that make incredible power too.

The point I was making was, for any given XXXwhp engine, most V8s with XXXwhp will generate more low end torque and area under the torque curve than a XXXwhp 4 cylinder.

The S2K dyno graph you posted above does nothing to refute this point.

Furthermore, despite the apples to oranges comparison you are making, I would point out that my lowly 100whp Rover V8 was already producing 150ft/lbs by 2000rpm, whereas the mighty 491whp s2k engine you posted didn't start producing 150ft/lbs of torque until 2600 rpm, so below 2600rpm, my lowly 100whp Rover V8 engine STILL produces more torque than your mighty 491whp s2k engine. This only serves to re-enforce my point about V8s making more low end torque than 4 cylinders!

[BlownMGB-V8]

What does that s2k do under 2 grand? Can it cruise at 70mph and about 1800rpm? Can it pull a hill and pass at that speed without downshifting?

If all you plan to do is race it might be great. But if you plan to drive it in the real world at all it looks like a pretty severe mismatch.

Jim

[pointnette]

I think this is a bit closer to what you're talking about. It's not stock, but it's not that heavily modified either, which makes it a good 4 cylinder engine to compare with a slightly modded Rover V8.
http://www.gomog.com/reviews/GM44/GM44.html

Stan