MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - V6 vs. V8

Hey!

I am curious about the performance potential of the 60 degree 2.8/3.4 V6 compared to the Buick/Rover 215/3.5/3.9/4.0. Is the torque comparable? Which one is has performance parts to create a 7000 rpm revving engine?

Thanks!
Jamie
H. J. Rodgers II

Jamie,
I sent you an email with a dyno run of a 100,000 mile 3.4L motor almost perfectly stock! 230 Tq at the flywheel and 192.6 at the wheels... @ the wheels, tq is already at 175 lbsft at 2,200 RPM and is still at 175 lbsft at 4,600 RPM.

The GM 60 degree has performance parts all over and alot can be done with these. Anyways, let me know if the chart didnt come through.

Regards,

-BMC.
BMC Brian McCullough

Jamie
I have a v-6 conversion and love it. I think it is a perfect combo, weight to hp and torque to weight. It drives great, handles great.
If you go to classicconversions.com you can pull up numbers on both the v-6 and the 215 or rover 3.5.

All this being said I am in the process of doing a 302 conversion. I am a product of the 60's and there is no sound like a nicely balanced v-8. The v-6 is a straight forward conversion and if it were a choice of the 3.5 or 3.4 v-6 there would be no question I would do the 3.4.

The 302 is another animal. I will be running 362 ft lb of touque at 4600 and 347hp at 5200rpm{I previously stated 355}. This may be moe power than needed but it idles kike a stock motor but when you want to turn it on it is there.

All options are good, you just need to choose where you want to stop.
Garret
garret

Garrett,

This is the link:

http://www.classicconversionseng.com

I feel that those numbers while, as published, are misleading when it comes to 215/3.5L conversions. Those are from the factory, flywheel numbers for a production engine. Most conversions using a massaged 215/3.5L will be putting 175-200 HP to the rear wheels.

Heck, my stone stock '63 215 (okay, it's the factory 200 HP version) w/carter 500 & no air cleaner dyno'd @ 162 the rear wheels. So, it doesn't take much to beat those published factory numbers.

Bill,

Please correct the spelling for Camaro on your website. As a looong time owner (24 yrs) of a '68 Camaro, it pains me to see it spelled with an "e". ;)Otherwise, nice website!
Carl Floyd

Carl,

Yup. I agree.. all motors can produce more once you start tuning. Stick a bigger carb or better parts on an injected motor and you get more.. How about placing a catty converter, smog pump, EGR and all the rest of the emmissions systems on a 1963 Buick V8 and see what happens? ;-)

The GM 60 degree V6 motors all had to go through emmissions and BHP and Tq is rated to the best of my knowledge as is running with the correct exhaust system and all components. If we start removing and modifying a 60 degree, power can add up quick as well... Start with base power of all:

3.5L V8
BOP 2bbl:
performance model with 4 bbl:
MGB GT V8 twin SU: 137 BHP/ xxx lbsft
Rovor SD1:

3.9L V8 and so on..

I think stating base numbers helps alot when you consider a motor and know aproximately what can be added or removed from a certain model year. Do you agree?

-BMC.

BMC Brian McCullough

I think there's a lot to be said for doing a V6 conversion. Don't get me wrong, I love the power of what I've got. But for a car that's fun and trouble free, and a relatively easy swap for more power and good fuel economy, in short a car you'll truely enjoy driving every day of the week and then even more on weekends, I think a V6 conversion would be hard to beat.

Looking back, one of the true joys of the stock MGB was learning to get every ounce of performance out of the machine by driving it to it's limits. Well, with the high horsepower conversions out there it's a whole different ballgame becauses you simply cannot do the things you can with the stocker. By this I mean, if you floor the gas coming out of a turn or sometimes all the way through, you aren't likely to stay in contact with the road for long. It takes a whole lot less to get seriously out of control, and a good deal more finesse with the right foot is required. No more than these cars weigh, the V6 gives a fine balance of power, more than adequate performance, ease of installation, plenty of room in the engine bay, and a minimum of cooling concerns. It would have been an excellent choice, had the factory had that option. I think it is an excellent choice for anyone considering a swap. For a somewhat comparable perspective check out what the guys on the supercharger board have said about how they like their cars. They are by and large wildly enthusiastic about it, and you know what? I seriously doubt a ride in a V8-MGB is going to change the mind of most of them, even though they have nowhere near the power.

Now for us old V8 guys of course that just won't do, but we're willing to live with the downside of our illness. If we have to we can learn intermediate throttle positions, we can buy and install high efficiency radiators and othere necessary accessories, and even live with having to have surgery to allow the transplant, all in the quest for that V8 sound and the ever important bragging rights. But it doesn't mean we're right.

Jim
Jim Blackwood

Good show Jim!

Whatever floats your boat with Your car is right to you and we are not talking anywheres close to politics, morals or religions so evryhting else is personal interpretation.. V8's right in some cases and wrong in others...

In terms of BHP/Tq, pound for pound (weight wise!), dollar for dollar, and cubic inch (centimeter) for so on and so forth, I think that all figures have to be put in place. If a person is willing to spend the money for the 3.9 or larger BOP/R rebuilt to a spirited style of motor, then they should comepare to the same in the Ford V8 and the same to the GM V6. Find pricing, 0-60 times, handling and all the rest. I, without ever seeing a dyno sheet on teh Ford 302 conversion in an MG would naturally assume that the BHP/Tq for a 400 BHP and torque around the same would cost less to build then the 204CI "3.4L" V6 and hold up better and probably cost less tehn a BOP/R V8 with the same power. 0-60 times compared to a 200 BHP car? not that much improved unless money is spent on everything else too.. On the other hand, a 3.4L V6 costs alot less then a BOP/R V8 and has about the same BHP and Tq (sometimes way more) at about half the cost. The Ford needs an awful lot to handle well, aluminium everything which adds even more expense and might bring the BOP/R V8 back into the running. As you know, we alll like to bench race the "what ifs" :-)

I guess getting back to Jamies question though, I have heard that the BOP/R is not a high revving motor and does not like that much due to its overall design.
-Speaking from hearsay, and lots of it.

Jamie, did you get my email with the dyno chart?

BTW: I really like Jim B's conversion.

-BMC.
BMC Brian McCullough

"I think stating base numbers helps alot when you consider a motor and know aproximately what can be added or removed from a certain model year. Do you agree?"

Brian,

Sure. It's a place to start. Technology does march on, as well. The 265HP 3.5L V6 in my wife's '03 Nissan Maxima is a hoot. I grew up in the muscle car era, though. Tha is a big reason why I prefer V8s.

Ironically, when in high school ('72-') I would daydream about putting a Capri V6 in my Dad's '63 MGB. I had no idea that they were building 3.5L MGBs at the factory. Now, there are much better V6 choices, yet I want a V8. ;)

As for mods, my engine really doesn't have any. The Carter carb was chosen because the factory 4bbl. won't clear (I still have it). Many will argue that the bigger Carter does not help make more power on anything eeven remotely close to a stock 215/3.5.

Dyno sheet:

I can't find my dyno sheet from the last V8 meet. I can tell you that the quality was poor (dot-matrix printer) and I could make no sense of it. The operator would read us the numbers from the dyno's memory of the run.

If you want to see a dyno sheet of a warmed over 3.5L putting 175HP to the rear wheels, Martyn Harvey used to have his posted on his website. I'll check to see if it is still up.
Carl Floyd

Sounds good Carl..

FWIW, Reliable BHP and Tq will probably increase another 20 to 50% over the next 15 years and then peak until the day we all drive wheelless nuke powered Jetsonmobiles. :-) The piston engine, as my best machine shop loves to remind me, is outdated.

If you ever find the sheet, I am interested to see. Maybe Dan, Jim or one of the other guys has already started to post dyno sheets and info on thier websites for the various conversions?

-BMC.
BMC Brian McCullough

This thread was discussed between 10/01/2005 and 18/01/2005

MG MGB GT V8 Factory Originals Technical index

This thread is from the archives. Join the live MG MGB GT V8 Factory Originals Technical BBS now