My exhaust kills small animals. Normal?

Several have posted DYNO numbers here for older cars and new QV cars. A properly tuned 76/77 car should have ~190+RWHP and a QV about the same. The later carb’d cars have different cams, more emissions equip. and therefore will have less power unless some modifications are done. The FI cars are the weakest of all.

I’ve never had mine dyno’d but I was considering it after I rebuild the carbs this fall. I know they need to be done. But two others who have 78 and 79 cars drove mine, and they both commented that mine definitely had more get up and go then there’s did. And both had cars that were in proper tune.

Ferrari quotes 255BHP for all the carb’d cars, 205 for the FI cars and 235 for the QV cars. The number for the QV cars is the only one that’s correct on US cars. The 255 is correct for Euro cars but the US cars never had that much power. The FI cars had closer to 195BHP

 

This is wrong! But a common mistake. The early North American carb cars (75-77) were rated around 240hp. The 78-79 carb North American spec cars were rated at 205hp. The early 2valve FI cars were also rated at 205hp, but were commonly thought to be more realistically, around 180-190 hp.

Dave

 

Could be the dyno, but on any Ferrari over 15 years old, I would suspect the distributors are not advancing, and would have those checked first. Here in the NW, we have tested lot's of various Ferraris, and that was the most common cause of cars that did not meet their HP numbers.....

Davfe

 

That's what I said before (240BHP) and I also said that 255BHP was correct for the Euro Carb's cars only.

~190+RWHP = Rear Wheel Horse Power. Using 17% loss quoted here many times = ~225+BHP (or CLOSE to 240BHP). Read the whole post before you correct someone.

 

Nothing is wrong with your car, or mine. They do all do that without thermal reactor, and w/o air pump.

 

this is normal for a 70's car. I have the same problem and everything is set right. I love the smell if I didn't i would get a prius!

Bring on the next Ice age!!!

 

LOL! i started to laugh as soon i as i saw the title of this thread.LOL!!

 

LOL! i started to laugh as soon i as i saw the title of this thread.LOL!!

 

no soot, no runny eyes here. carb 308, 55 idle, 135 mains, 200 air, no cats or airpump, has ansa and k&n filter. i am ordering , through a friend a set of 4 air cleaner with individual k&n air filters. his carb 308 has them ( we put them on last sunday) and there was a remarkable difference. one thing i learned that is critical is that with the o60 idle jets, you cant get the idel screws out very far, where as with the 055, ( i am using them now) i can have the screws backed way out and the car runs great and not rich. my plugs are all perfect as far as mixture goes ( ngk bp5es ?) it important to understand that the idle mixture screws also let in MORE AIR as well as fuel. the 060 's are too much for my car. all the backfiring and popping is gone now also. see my ad on ferrariads and the collector car trader. i want a carb boxer, the 308 will be driven and cared for until it sells or is traded in.

 

Michael
Great photos!
There has been discussion in the past here on the value of the stock air box with cool air ducting versus individual carb filters as you show. Empirically (and Ferrari must think so as well) the cooler air would be better for hp and response than the individual filters.
You say below that there was a remarkable difference - was that just in drivability, power, response or simply mixture control? Could you tell us comparatively what the difference was?

Anecdotally in my case at least, my carb'd car felt MUCH peppier with the stock air box off, and on the dyno showed as much as a 14 or so rwhp increase (definitely noticible depending on jetting) without the box. Now we've all endured the endless K&N threads and don't want to go back there and rehash, but I would be very interested in you and your friend's experiences with the separate air filter boxes as part of me wants to believe that an increased airflow with individual freer flowing filters would overcome any temperature effects.

Many thanks, and just tryin' to think out side the (air)box,
rt

 

Ah, I see I did miss you last sentence...but you confused me, as you are mixing EURO and North American specs in the previous sentence:

"Ferrari quotes 255BHP for all the carb’d cars, 205 for the FI cars and 235 for the QV cars. The number for the QV cars is the only one that’s correct on US cars. "

According to a couple reference books I have read (admittedly these are not always the gospel):

Euro 308's were rated:
75-79 255hp
80 230hp
81-82 214 hp
83-85 235-240

North American 308's were rated:
75-77 240hp
78-79 205hp
80-82 205hp (but considered actually lower)
83-85 230-235hp


Dave

 

the car sounded, and drove much MUCH better. the throttle response ( difference) was VERY noticable. i am aware of the fact that cooler, denser air is a better idea. i drive my car as a toy, in very little traffic, so its not going to ' soak" with the heat. the carb sounds are well worth the trade off with warmer air. i also feel that k&n filters allow more dirt ect in your engine. but frankly, i dont really care as i change the oil every 3 months or so , excluding miles. for those that drive thier cars in heavy traffic with the a/c on, i could see these filters as not bieng ideal. but for my use they will be just right!

oh yes, just my thoughts , but i believe he stock box restriccts flow at higher rpm, its a trade off since the car is meant to be allowed to drive in all sorts of weather. i feel the carbs will suck in cool air from the low pressure area created by the back of the car at normal speeds. the sloots should not allow too much rain into the back that i wont beable to drive it if caught in rain, i wont go out in the rain on purpose in the ferrari, again for my use i think they will work well.
i am also wondering if the additional air from the now open air cleaner duct to the engine compartment will make any difference in cooling. will update if i see any difference.

 

Can you share how much for the filters, etc and source?

 

Hello everyone. My name is Joe Frazar. Mike's picture of the K&N Filters on the Carb 308 is my car. Some explination might be justified. My primary reason for installing these was to make fine adjustments on my carbs. After taking the airbox off 3 times I had to find a better way. I must say I saw some nasty things said about using individual filters on a carb 308. Forced induction lost, hot air - all that kind of stuff. I call BS on that. Look at the size of the air inlet to the air box vs. the size of the carb throats alone. I could go on. I have run individual filters on many cars I have had with carbs. The sound, the response, ease of adjustment ect. and it can all be put back to stock in 30min if needed.

Installation was easy. I called pierce manifolds in Ca. I ordered the k&n filters for DCNF's 2 1/2 inch tall. The stock air box gaskets slip right in on the bases and the velocity stacks slide right in. Bolt it up, oil the filters, snap on the lids. DONE. Cost was $26 per filter.

 

In three chassis dyno runs as I was setting up my jetting, I had one run with open air horns, one with just the airbox and NO filter and one with airbox and K&N filter.
Best I remember with the jets I had at the time, the airbox with no filter lost about 5-6 rwhp over the open air horns, and the airbox with filter lost 10 - 12 rwhp over open air horns.

The dyno technician said he had seen this before, and that it was best addressed with a hole saw......

best
rt

 

one thing about dyno runs, there is no ram air effect. i believe there must be some advantage to having the carbs pull the cool air in through the SLATS in the engine compartment, as well as having the other air cleaner opening allowing more air into the engine compartment.
as Birdman implied, i am almost positive i will have to retune the carbs for winter weather and the addition of the open air cleaners when i order / get them. i have driven in and ridden in Joe Frazar's carb 308 throughout his tuning process and there was a definative seat of the pants change. i also loved the sounds the carbs make, which is amplified by the open air cleaners. really, as old and slow as my 308 is, it aint no race car, but i feel this will be a cheap , fun addition to the car. i really could care less if it sells or not, i will keep playing with it until i get too bored with it. i may go with 060 idle jets ( and i already have them), but i want to look into emulsion tube changes as i have an idea i would like to try.... more on that later. michael

 

Perhaps someone remembers the thread better than me, but some clever reputable FChatter actually measured the ram air at highway speeds and found the increased air pressure in the box to be marginal, and even barely measurable. Don't know how accurate it was, but if it's on FerrariChat, it must be true, right? (Just kidding).

 

Michael,
I have .60 idle jets on my 79 308, but the mains are 130, with 200 air corrector. My car has not cats' or air pump. It idles great now, and has pretty good low end power. It's a pretty big difference between the .55s and .60s
Jim

 

I recall the discussion you're referring to and you're right--speaking theoretically (disregarding pulling air from a high or low pressure area on the car's body), I calculated once the effect of ram air to be about the difference between a "good day" and a "bad day" at the track in terms of barometer. I forget how many inches of Mercury it was, but it was about the swing of the baro. At 100mph. Ram air isn't all that important, but I'm a big fan of cool air. However, for recreational, spirited driving it might not be a major issue. I'd plumb a nice, big hose from that air duct on the side! I've wanted to design a system that would essentially give you an airbox mounted to the engine cover, but there would certainly need to be some effort given to accounting for relative movement.

 

I've always thought an interesting alternative would be to design a plexiglass (see-through) air box, or air box cover. You'd still have the ram-air effect, but could also see those beautiful carbs.

Do you think this is possible?

Dom

 

Forza issue #48 has an article titled "The Scientific Method", which discusses a carbed 308GT4 being restored by Carobu Engineering. According to this article, removing the airbox lid is counterproductive to power. They also found thair switching from the stock paper filter to a K&N resulted in a slight decrease in overall horepower.

Dom

 

Bird,
Yes, exactly - the 3 dyno runs were made bonnet open to quantify airbox, filter losses and A/F changes as I wasn't thinking (at the time) of going without a stock airbox and filter. However, the road test was made with stock air horns and without the airbox entirely and bonnet down on the roads of America one night. While I can't quantify, there was sure a qualitative difference in response and 'umpf' on throttle application that just made me giddy with glee - I didn't want to get out of the car. With the box and K&N, the response is still way better than the previous Kjet FI, but also definitely muted and not as 'edgy' as the open system. Of course I would never routinely drive around sans airbox, but no kiddin', the seat of the pants difference is quite remarkable.
best
russ