Hi all. I'm about to get my old mighty boy back. It's a bit rusty but mechanically sound.
Now my question is, does the stock F5A respond well to basic mods (such as the the 1L charade carby that is rumoured to fit, and a bigger exhaust)?
My plan was to initally run a basic water injection setup (vacuum operated, for internal cleaning more than anything else), and run the engine on 98 (I have access to a dyno for tuning, and I can modify the distributor if it is of benifit).
After that would depend on your advice. Intake or exhaust first? It would just be a 1L charade carby swap, and a collector back exhaust, using whatever mufflers fit and are cheap at the time.
I say collector back exhaust because if I come across a manual suzuki hatch that's looking for a place to die I have no issues in ripping out it's heart and soul, and the F8 is rumoured to have different manifold porting.
I would prefer some numbers here, saying 'it goes heaps harder mate' is nice, but I need numbers. My ass-dyno is currently only calibrated for the faster cars (110-300rwkw), so the car is going to be slow for me anyway... If you have some 1/4 mile, dyno, or even in gear split figures it would be good.
Also, how well do these engines respond to a port and polish while retaining the original cam? Personally I would expect to go from 30kw (F8 stock) to around 40 with porting, carby, and exhaust mods, but you guys are the ones who have done this all before.
For those that are wondering, I see this mechanically simple car as a cheap way to learn rather than a $ per anything excercise (except maybe $ per pizza delivered)
Tune-up and basic mods
While an extra 10kw does not sound like much you have to remember that it is effectively an extra 33% over what the engine is making now. You are not going to get that sort of power increase with just a set of extractors carby and port job I am sorry. Maybe 5kw at best. I am only expecting an extra 10kw out of my G10A at that is with a pretty decent cam, port job extractors and conversion to EFI.
Cheers
Paul
Cheers
Paul
BLSTIC wrote:
Now my question is, does the stock F5A respond well to basic mods
So what motor do you have, F5A or F8B?BLSTIC wrote:Personally I would expect to go from 30kw (F8 stock) to around 40 with porting, carby, and exhaust mods, but you guys are the ones who have done this all before.
F8B EFI turbo - Three pots and a snail.
I have an F5A. The port job was only if I got an F8 and could do it while the car was still running around.
I'm aware of the maths regarding percentages. I would have expected at least a 33% gain from porting, manifold, carby, and extractors on an old 202, and that's what I based the 10kw on. Of course that doesn't take into account that the engine has a higher specific power output out of the box.
I'm aware of the maths regarding percentages. I would have expected at least a 33% gain from porting, manifold, carby, and extractors on an old 202, and that's what I based the 10kw on. Of course that doesn't take into account that the engine has a higher specific power output out of the box.
Okay, so back to your original question: Will an F5A respond well to performance mods? Sadly, no. 
I think you'd be forcing excrement up an incline to get a 5kw gain from bolt-on N/A mods to an 20kw F5A. (Considering the F8B has an extra 33% capacity to get a 10kw gain, and adding EFI and a low-boost turbo to an F8B only produces roughly 15kw extra on top of that.)
If you want decent gains from an F5A I would suggest upping the compression, grinding the cam and porting the head... or put up with the standard motor and find an F8B to rebuild with those mods in mind. (Don't forget the matching gearbox.)
With the exhaust, it is tuned length runners or nothing. I've fitted various types of collector-back exhausts and they do zero for performance. The game is won and lost at the top, and if you build a decent set of extractors for an F8B they will fit your F5A in the meantime - just allow for the extra F8B block height in the J pipe.
I think you'd be forcing excrement up an incline to get a 5kw gain from bolt-on N/A mods to an 20kw F5A. (Considering the F8B has an extra 33% capacity to get a 10kw gain, and adding EFI and a low-boost turbo to an F8B only produces roughly 15kw extra on top of that.)
If you want decent gains from an F5A I would suggest upping the compression, grinding the cam and porting the head... or put up with the standard motor and find an F8B to rebuild with those mods in mind. (Don't forget the matching gearbox.)
With the exhaust, it is tuned length runners or nothing. I've fitted various types of collector-back exhausts and they do zero for performance. The game is won and lost at the top, and if you build a decent set of extractors for an F8B they will fit your F5A in the meantime - just allow for the extra F8B block height in the J pipe.
F8B EFI turbo - Three pots and a snail.
BLSTIC wrote:In that case I won't bother. I'll just tune it for 98, do some water injection, and drive it.
water injection
....its not miles per gallon its smiles per gallon....
1990 f10a supercarry 5speed
small van big plan
1990 f10a supercarry 5speed
small van big plan
Water injection is a synch, and perfectly safe if done properly. Especially seeing as the system I will use will just be a small amount on over-run to aid with combustion chamber cleaning. I have used this exact system before on one of my cars (A 1990 Legacy GT) and it worked flawlessly for cleaning the combustion chamber (evident with a before and after test of my spark plugs). Detonation was also reduced from having no carbon present.
Also other systems (such as one that uses ported vacuum) are equally reliable, you just don't want to run out of water if you have tuned for them.
Incedentally seeing as I'm only using it under engine braking, running out of water will have no effect on the running of the engine...
Also other systems (such as one that uses ported vacuum) are equally reliable, you just don't want to run out of water if you have tuned for them.
Incedentally seeing as I'm only using it under engine braking, running out of water will have no effect on the running of the engine...
Do those people with F8B's (modified or not) get similar to original fuel economy?
I'm having second thoughts about NOT doing the swap (assuming I find a comlete hatch). And I looked around, F8B rebuild parts are everywhere... so I might as well have a play with it.
What are the limits of the F8B bottom end? How hard can I rev it, and how much torque can it make, before things start to bend?
I'm having second thoughts about NOT doing the swap (assuming I find a comlete hatch). And I looked around, F8B rebuild parts are everywhere... so I might as well have a play with it.
What are the limits of the F8B bottom end? How hard can I rev it, and how much torque can it make, before things start to bend?
I'd say the economy of an F8B is on par, if not better than an F5A because you don't have to work it as hard. I've never done an accurate recorded comparison, but kms-per tank seems about the same across the MB's I have owned with both motors. (F8B does use noticeably less juice on the open road through better gearing.)
The reliable rev ceiling for a stock F8B is about 6.5k, with peak torque and power produced well before that. Limiting factors of the motor are tuning, pistons and rods - in that order. If you modify the motor make sure it is tuned right and you shouldn't blow holes in the pistons, or bend the pencil-thin rods. Running lean will wreck the pistons/valves in these motors really quickly.
The reliable rev ceiling for a stock F8B is about 6.5k, with peak torque and power produced well before that. Limiting factors of the motor are tuning, pistons and rods - in that order. If you modify the motor make sure it is tuned right and you shouldn't blow holes in the pistons, or bend the pencil-thin rods. Running lean will wreck the pistons/valves in these motors really quickly.
F8B EFI turbo - Three pots and a snail.
So who has done an all out F8 build? I expect that at some point the pistons and rods will fail regardless of whether it pings or overheats. Building a top end is easy, but I can't imagine too many people have hypereutectic pistons and forged rods for the F8 lying around.
ooh ooh (excited) what about the F8C Daewoo Matiz? I'm gonna do some looking around and see if I can't find anything on interchangability , if I can't I'll start a new thread in here...
ooh ooh (excited) what about the F8C Daewoo Matiz? I'm gonna do some looking around and see if I can't find anything on interchangability , if I can't I'll start a new thread in here...
The F8C is a Chinese reverse-engineered F8B, with a slightly different head design, plastic intake manifold and EFI. It isn't a direct bolt-in to an MB engine bay due to the mount castings and gearbox/driveshaft config.
The most I have seen anyone do to the bottom end of an F8B is a bore and offset crank grind - maybe shot-peened rods. In standard trim the bottom end is good enough to cope with just about any N/A treatment you might give it, and will handle boosting just fine to about 10psi if tuned correctly. There aren't any performance pistons or rods available off-the-shelf.
Rather than try and build bullet-proof F5/8 most people chasing performance look to the F6A turbo or keep going up the CC ladder to the G10A.
The most I have seen anyone do to the bottom end of an F8B is a bore and offset crank grind - maybe shot-peened rods. In standard trim the bottom end is good enough to cope with just about any N/A treatment you might give it, and will handle boosting just fine to about 10psi if tuned correctly. There aren't any performance pistons or rods available off-the-shelf.
Rather than try and build bullet-proof F5/8 most people chasing performance look to the F6A turbo or keep going up the CC ladder to the G10A.
F8B EFI turbo - Three pots and a snail.
Hmmm... It's worth trying to set some kind of end goal here before I start... Just how fast can a lightly tweaked F8B powered mighty boy get down the quarter?
I imagine that with higher compression, a port job, extractors, and a decent carby it would be putting out a bit more than 30kw.
What times have you got out of your EFI/Turbo example?
This is all to help me decide whether it's worth modifying. If I can't get to the point where I can beat a 15 year old falcon or commodore I'll just tidy it up (stock) as I drive it, while building something with a bigger motor in the background (I've had fun in a daihatsu applause, and it's engine management system looks easy enough to fool for boost).
I imagine that with higher compression, a port job, extractors, and a decent carby it would be putting out a bit more than 30kw.
What times have you got out of your EFI/Turbo example?
This is all to help me decide whether it's worth modifying. If I can't get to the point where I can beat a 15 year old falcon or commodore I'll just tidy it up (stock) as I drive it, while building something with a bigger motor in the background (I've had fun in a daihatsu applause, and it's engine management system looks easy enough to fool for boost).
I doubt that keeping it N/A you will do much better than a 19 second pass from an F8B. From memory a stock F5A does it in 26. Measured on a G-Tech I got roughly 20 seconds q/m and 11sec 0-100 from an F8B with a Weber carby and extractors.
F8B EFI turbo - Three pots and a snail.
Well if getting better than a 19 is going to be harder than that n/a I won't bother with mild mods.
What did you get down the quarter with your boosted F8 (both when it was carby and when efi)? If it can churn out a high 15/low 16 I'm keen to boost an F8.
Now to read up on blow-through carby turbo setups...
What did you get down the quarter with your boosted F8 (both when it was carby and when efi)? If it can churn out a high 15/low 16 I'm keen to boost an F8.
Now to read up on blow-through carby turbo setups...