how can i increase the bhp of my mgb gt 1800?

how can i increase the bhp of my mgb gt 1800?

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Discussion

llohcins

Original Poster:

32 posts

128 months

Saturday 17th April 2010
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How can i increase the bhp of my mgb gt 1800 rubber bumper 1979? There are the obvious performance air filters but for the twin su carbs thats a good £100 of filters and I am not sure how much of an effect it would have? The car runs well but it doesnt feel like its giving as much punch as i want from a 1800 that doesnt weigh much. Any advice?

wildoliver

8,280 posts

176 months

Sunday 18th April 2010
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To be honest if your worried about spending £100 on filters then tuning the B series is going to be a waste of time for you.

To get any noticeable power increase it will cost you quite a lot more than that.

Starting point is setting the engine up properly, most Bs I have owned and driven have been terribly set up. Just getting the engine right makes a huge difference. However these are not quick cars.

Next step is a set of filters and exhaust.

The step after this is best tackled as one step. Rebore, flowed head, fast road cam. However you will spend circa 1K plus doing most of the work yourself and the end result will return very little.

Your best off deciding if you want an enjoyable to drive classic car with enough performance to have fun, or if you want to make it in to something very quick indeed, if so then different engine is the way to go, just be aware that going this route will just highlight the primitive suspension and brakes even more.

Bs are not fast cars, they are great fun and can press on with ease but if you want a quick sports car it will save you a lot of hassle and money to just buy one.

llohcins

Original Poster:

32 posts

128 months

Sunday 18th April 2010
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Thanks for that, I did susspect it would be the case. It is fun to drive despite its lack of power, maybe i'll just give it a decent service and enjoy it as it is. It just seems that an 1800 should have more to give. Thanks again

alfa pint

3,856 posts

171 months

Sunday 18th April 2010
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It's a very old 1800 with a really pants head design. When I say old, we're talking 60 odd year old design. 95 bhp at the flywheel sort of power.

Getting the carbs set up properly will make a difference. Airfilters help a bit, but you won't really notice the difference until you start making the engine breathe properly. My old B had a reworked head, an LCB manifold and a straight through exhaust with only the back silencer, tweaked SUs, K+N airfilters, a stage 2 cam (a bit excessive, v lumpy, fast road cam would have been better), a lightened and balanced crank and flywheel, electronic ignition, fast road dizzy and a list of similar mods to the suspension and minor upgrades to the brakes. I was still only getting about 105-100 bhp at the flywheel, but at least the torque was there to overtake like it was a more modern 1800.

I've seen a B with 145 bhp from the B series engine, but it cost more than my car and didn't like running in traffic. the only other way forward is an engine transplant. Or just accept that it was a reasonably fast car in 1970 and it's now 2010.....

Mighty Flex

852 posts

131 months

Sunday 18th April 2010
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rover v8. biglaugh

hidetheelephants

16,357 posts

153 months

Sunday 18th April 2010
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Mighty Flex said:
rover v8. biglaugh
This and some vented disc brakes.

CDP

6,339 posts

214 months

Sunday 18th April 2010
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alfa pint said:
...just accept that it was a reasonably fast car in 1970 and it's now 2010.....
A really good service (ignition and carbs in particular) combined with rolling road setup. Also if it's an old engine check the compression.

If you're intent on transplants how about the T-Series?

mgtony

3,472 posts

150 months

Sunday 18th April 2010
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This might be the answer;

http://www.moss-europe.co.uk/Shop/ViewProducts.asp...

smile

Just seen the price, frown

Edited by mgtony on Sunday 18th April 18:27

hidetheelephants

16,357 posts

153 months

Sunday 18th April 2010
quotequote all
CDP said:
alfa pint said:
...just accept that it was a reasonably fast car in 1970 and it's now 2010.....
A really good service (ignition and carbs in particular) combined with rolling road setup. Also if it's an old engine check the compression.

If you're intent on transplants how about the T-Series?
Oooh, T16 would be interesting. Transplants into TR7s are popular, I always fancied putting one in a P6. A relatively easy(and cheap) 150bhp, or 200+ if you got a turbo.

CDP

6,339 posts

214 months

Sunday 18th April 2010
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hidetheelephants said:
CDP said:
alfa pint said:
...just accept that it was a reasonably fast car in 1970 and it's now 2010.....
A really good service (ignition and carbs in particular) combined with rolling road setup. Also if it's an old engine check the compression.

If you're intent on transplants how about the T-Series?
Oooh, T16 would be interesting. Transplants into TR7s are popular, I always fancied putting one in a P6. A relatively easy(and cheap) 150bhp, or 200+ if you got a turbo.
The TR7 is a better place to start with when it comes to power. Not especially good, just better.

Having driven a standard rubber bumper MGB-GT round Hethel I'd suggest it's normal 1.8 engine is probably matched to it's handling. You'll need to upgrade the suspension at the same time as the engine. I must admit I didn't try the brakes (throwing the car into corners completely sideways made far more sense) but they might not be up to the job either.

Good job upgrade kits are relatively cheap.





SEH1800

13 posts

145 months

Sunday 18th April 2010
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You could always go the other route and try to lighten the car... aren't there loads of fiberglass and/or alloy replacement panels for B's? Seems that later B's have lots of flab on them but maybe I'm wrong about that. Of course, this wouldn't be exactly an "economical" venture either.
With the money you'd spend on squeezing a noticeable amount of HP out of the B-series engine you could probably buy a late Alfa Spider for days when you want to be seriously quick, and keep the B for days when the Alfa is at the mechanic! laugh

CDP

6,339 posts

214 months

Monday 19th April 2010
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SEH1800 said:
You could always go the other route and try to lighten the car... aren't there loads of fiberglass and/or alloy replacement panels for B's? Seems that later B's have lots of flab on them but maybe I'm wrong about that. Of course, this wouldn't be exactly an "economical" venture either.
With the money you'd spend on squeezing a noticeable amount of HP out of the B-series engine you could probably buy a late Alfa Spider for days when you want to be seriously quick, and keep the B for days when the Alfa is at the mechanic! laugh
Apparently the irons behind those plastic bumpers are extremely heavy. Removing them shouldn't be too difficult or expensive.


alfa pint

3,856 posts

171 months

Monday 19th April 2010
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CDP said:
SEH1800 said:
You could always go the other route and try to lighten the car... aren't there loads of fiberglass and/or alloy replacement panels for B's? Seems that later B's have lots of flab on them but maybe I'm wrong about that. Of course, this wouldn't be exactly an "economical" venture either.
With the money you'd spend on squeezing a noticeable amount of HP out of the B-series engine you could probably buy a late Alfa Spider for days when you want to be seriously quick, and keep the B for days when the Alfa is at the mechanic! laugh
Apparently the irons behind those plastic bumpers are extremely heavy. Removing them shouldn't be too difficult or expensive.
The rubber bumpers are 44kg each. And exactly where you don't want that sort of weight...chrome bumpered my car as soon as I could afford to do so. There's only so much weight you can reduce unfortunately - the car's so heavy because of the overengineered rigidity of the chassis rather than the excessive weight of the panels.

SEH1800

13 posts

145 months

Monday 19th April 2010
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Hmm, sounds like you could then make some kind of improvement though, if what you're saying is the bumpers alone are costing almost 100kg extra weight.

Then tackle the interior, get rid of those heavy stock seats and replace with Cobra/Corbeaus which can only weigh about 7kg each, carpet, soundproofing, get some nice bonnet straps and ditch the bonnet/boot latch mechanisms, etc.

All together could probably lighten the car at least 200Kg which ain't bad...it's like carrying 2 heavy mates around in the car (or 3 nice girls depending on your imagination wink )

Then with a little simple tuning (BMC B-Series Tuning Manual stage 1 is a good start) to get a little extra torque it could make some difference without breaking the bank?

Having said that though, one of the biggest culprits in the weight department apparently is the B-series block itself! Back to square one...

Edited by SEH1800 on Monday 19th April 10:41

SB - Nigel

7,898 posts

194 months

Monday 19th April 2010
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Same answer I always give - a FULL and PROPER service

Do the 36,000 mile service requirements in the Owners (handbook) Manual if you've not got one then buy one, a good investment at about £6

Concentrating on the engine alone is a bad idea and will not give you the full potential of power available already

In addition to above unless they're changed (to good quality parts) recently I'd also replace:

ignition leads
rotor arm and dissy cap
(possibly the coil)

when you can afford to:

1)swap to full electronic 1-2-3 dissy
2)K&N air filters,
3)stub stacks, sports exhaust and rolling road tune up

chormy

634 posts

156 months

Tuesday 20th April 2010
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My B has a zetec 1.8 in it on bike carbs, goes well and its a fairly easy swap. Like the rest if the b series engine in urs is well serviced and you check the compression is ok, I would suggest take the head off and clean it up valves etc then service the carbs , dissy and get the timing set up with carbs on a rolling road for 85 pound a hour its the best money spent , so long as you give them a car in the best nick possible within ur budget.

CDP

6,339 posts

214 months

Wednesday 21st April 2010
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It may be worth doing the compression test before spending a load of money on the ignition, head and carbs. If the compression's low you'll never get the proper power out of the engine. Blue smoke is another sign.

It's a simple enough engine that a rebuild isn't that hard though. You'd need to take the block to an engine builder for honing but that wouldn't be especially expensive if you reassemble it yourself. MG bits are generally pretty cheap.

Of course if the bottom end is still strong all the other points like ignition and servicing carbs will make a real difference quite cheaply. Just remember it's better to buy quality original than cheap "performance".

Bluetwo

3 posts

128 months

Wednesday 28th April 2010
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Hi all,
Just chucking my two pen'orth in, I had an R/B GT, ripped the bumpers off, fitted a Spax kit and lowered it to C/B ride height, that increased the 'grin factor'.
Got a proper C/B now (sort of), with uprated brakes, tightened up suspension, uprated ARB's, polybushes all through, and a little bit of engine tweaking. Just the basic stuff, nothing exciting. It's also been on a diet (no not rust induced laugh) and I've upped the tyre size a bit. It's not the quickest thing on the road by far, but hell it puts a grin on my face on the country lanes round my way! And startles a few 'moderns'...smile

SILICONE KID

14,946 posts

191 months

Saturday 13th November 2010
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Peter Burgess Peter Burgess Peterr Burgessrolleyes

pikeyboy

2,347 posts

174 months

Monday 29th November 2010
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Speak with my old mate Peter Burgess......