New X1/9 owner - looking for engine performance advice

S

slickdizzy

Low Mileage
Hello all, my name is Desmond, I'm the new owner of a '77 X1/9 after having wanted one for almost a decade! I guess I'm wondering where to start. It already has had a ton of brake & suspension work done, including sticky tires, so it must be time to go for more power! I'd like something that isn't too wild to drive on the street, but still an increase over stock.

My car is a little bit different - long story short, it was running the stock 1300 setup until about three years ago, when it spun a rod bearing pulling 1.1g's through a corner at Road America. Since then, it has had a 1500 from an '81 installed, but is running the original '77 intake manifold and carb. I also got virtually every other mechanical part from the '81 included in the sale (5-speed & subframe, suspension, spare brake assemblies, extra wheels even interior stuff, etc) so I have quite a bit to work with here.

I've done a little bit of research, and it seems like some serious head work is the best way to really open up the engine. I intend to do that, but I would like to stick to bolt-ons until the crappy Wisconsin wintertime rolls around, so I can actually enjoy the car for a while. The old PBS write ups seem to reccomend a Weber 34DMTR carb, however I have also read here that a 36DCNVA is a good way to go. Ideally I'd like something that will work with my stock head until I can get it ported that will also work afterward - it'd be nice to not buy two carb setups within a year, if possible. What do you guys recommend?

Outside of carbs, the rest of my questions are more general: what's everybody's favorite electronic ignition setup? Considering I plan on porting the head, should I just go ahead and throw an aftermarket exhaust setup on it? The last engine spun a bearing in a hard corner, should I be looking into an oil pan baffle? Also, what kind of internal engine work am I looking at for a streetable engine that will also see a large amount of track duty? I figure when I pull the engine this winter to go to town, I will swap in the 5-speed with a better flywheel and all that good stuff at the same time.

Any help is appreciated!
 
We can't help you until you post pics :nana:

Just kidding. Your running a carbed 1500 correct? You are on the right path with plans for a big valve head, large cam, ports etc etc, but in the meantime using standard Euro spec parts will give you noticeably more power over what you are currently running and at a fraction of the cost. Since spring is near and having your car drivable is key until winter, I would suggest Buy a Euro cam and the 34 carb along with either a Euro exhaust system or custom system using a header (header preferred) Run this setup until winter when the car can be torn apart in preparation for a BVHead and/or internal work. You can easily sell the Euro spec parts here or ebay and not loose money. You could also buy an extra head (for very little) and have it sent off to Matt to be worked/machined and ready to bolt right up in the fall; or you can source an existing BVH and forget about having the spare head machined (I'd send one to Matt personally). If your plans are 100% definite that a BVH is in your cars future, then forget the 34 and concentrate on trying to get a dual carb setup. If your not certain on the BVH or if budget dictates otherwise, a 34 would still work well. I'm sure others with much more knowledge on the topic of building these mills will chime in and get ya squared away.
 
Hi

I live in the western suburbs of Chicago do you have any plans to go to any autox event's? I've been going to autox event with my X for 14 years now .I'm the only X that goes to Autox events on a regular basses in the tri-state area.have you heard abut CHI-FLU club?
http://www.meetup.com/chicagolandfiatandlancia/
check it out we have allot of Wisconsin members it's free to be an online friend so join and check it out .there is a Tech day coming up this Saturday can you mack it with or with your X?
 
EDIT: I forgot to mention a single 36-42 DCNF and appropriate manifold is also an option and will work well with either Euro or BVH set-up's. Check with Steve C in Australia he's known to have a few of these kicking around. You mentioned a DCNVA <? I;m not familiar with that carb, but I believe the reason for the use of the Ferrari carb (DCNF), is that its linkage orientation is better suited to our cars and possibly emissions (or lack of) is better as well.
 
What is your budget and ratio of street -vs- track?

Much of what is in the PBS book is old, many of the suppliers are long gone, ie Cosworth pistons, Carrera dampers and etc..

There are better stuff available today.

*SCAT con rods.

*Wiesco pistons.

*ARP hardware.

*Isky Springs.

and the list goes on.. Set your realistic goals and budget, then go from there. Post and suggestion will be made.


Bernice
 
Budget would be within $1500 total, I would say half street and half track, honestly. Pics will come as soon as I find the connection cable for my camera..just moved and can't find the damn thing!
 
As my future daughter in law says

Go big or go home!
There was a debate between Chris O and Mad Matt a while ago.
After a year’s experience I would tend to agree with Chris (sorry Matt) the X needs as much as possible to give you the big smile. It is worth the financial stretch IMO. Go for it!
 
If your thrifty, $1500 can go a long way towards your goals. Several contributing factors are necessary IMO. First (assuming you've already researched well) figure out what parts/procedures are going to give you the most bang for the buck and make a plan. Second pound ebay/xweb/craigslist/regular parts suppliers etc etc etc for the best deals you can. Budget in the fact that your gonna go over budget, whether it be $12 here and there for grease's/nuts n bolts etc or an unforeseen $70 for a cam wheel & tension er you shouldn't have sold that is now needed:rolleyes2: My very best advice to give you is contact Matt Brannon at Midwest-Bayless (you'll probably get Thomas but that's okay he's pretty sharp too:p) Matt is a vendor, but don't necessarily let that shy you away. Matt races and builds x1/9's and has built/worked on/or seen just about every set-up imaginable from just about every imaginable budget. He will get you squared away and not sell you stuff you don't need or "up-sell" you (unless its in your best interest) just for that sake of turning a dollar.
 
There are 34dmtr's and then there are 34dmtr's... not all are alike. Some come with 22/24 venturis and some go right up to 25/27 venturis...obviously the larger one will flow a lot more air and is a lot more suitable for outright performance.

The trouble with the dmtr/datr/datra style of carbs is that they are fixed choke sizes, unless you start machining them out, but then you can't go back to a smaller size if you need to...

36 (or 40 or 42 or 44) DCNF style carb is better as it has removeable venturis, which can be swapped out to suit application. It's also a synchronous 2 barrel carb with both barrels opening at once, unlike the dntr/datr/datra style which is progressive.

DCNVA is just a type of carb in the DCN family...it has a similar body to the dcnf (though not interchangeble) but uses all the same intenal parts. It uses a manually operated strangler flap for choke enrichment (just like the dmtr) unlike the dcnf family of carbs that use a mixture enrichment device for starting / cold enrichment.

HOWEVER, the DCNva (or DCNf) don't fit onto the stock manifold. Ideally it should be mounted with the throttle shaft running parallel with the crankshaft, and that means it needs to spin 90 degrees to the stock mounting bolts.

It's actually a straighforward conversion if you have a milling machine and a TIG welder... but the 77USA manifold isn't what I would call a good starting point.

Euro 1500 carb manifold has ports approx 28.5mm, euro 1300 manifold has ports around 26.5mm, the USA spec manifolds are all smaller and more restictive, except for the early 1974 type, which is pretty close to the euro 1300. Sure you can remove metal and port it, but manifolds are tricky to get right, so it's easier for the novice to buy a manifold that suits.

I sell modified manifolds here in Australia, I also have a big stash of 36dcnva carbs. I start with the euro 1300 style and work from there, or the euro 1500 when I can get my hands on them. I'm planning on having some complete manifolds cast up (a copy of the alquati manifold for DCNF/DCNVA to X19) sometime this year, but as I've just spent a chunk of that budget buying a flow bench, that's gone down the list of priorities...

As for head work... well as a REALLY rough guide (because there are heaps of other factors involved)the number of CFM the head will flow at 28" of H2O is approx the HP you can expect that head to be able to produce. The stock euro 1500 head is good for approx 86cfm, and they make around 85hp, do nothing but port it to flow approx 98 CFM, and the same engine on the same day will produce around 98hp, the stock valve sizes can be used to get up to almost 120cfm...BUT... and this is a big but... you need to rest of the engine built to be capable to make power, your never going to get there with a low static compression ratio and a stock camshaft no matter how much flow you have ... it seems to work pretty much the same on all engines of this family to, 1300/1500/1600 and 1800, just the revs required to do the job drop as the capacity increases...

The other factor is low lift flow... a smaller valve can be made to flow similar numbers to a slightly larger one (i.e. 36 and 37.5mm valves both seem to max out at around 120/125cfm respectively)... at 400 thou (peak) lift ... BUT it will never make the same flow numbers at low valve lifts...and you go past the low lifts twice in every cycle, you only hit peak once... so it's very significant... the difference is a big percentage of flow, and that low lift flow increase is what delivers more torque and also assists with any cylinder ram effect (which can't be measured on a flow bench) at high revs...

So how big a valve is too big? well I use 38.5mm valves for anything up to 1500cc (cut back 39.5's)and this seems to be the best compromise between air flow and air speed...I can get up around 135 to 145cfm (depending on port size) and still keep port air speed up well over 300feet/sec... BUT now I've just been flow testing a new production late Tipo head, and with it's slightly different port shape and short side radius seems to hold port speed even with a 39.5mm valve...with flow figures out of the box of almost 125cfm and 325 feet/sec air speed... so with work should be good for numbers around 150 to 160cfm... which would be capable of around 150hp on top of the right engine.

Again, it will do this on top of a 1300/1500/1600 or 1800, but the other variables like camshaft lift/duration, carburettor sizing , compression ratio and the big one - REVS - will vary (and all components need to be matched) to get the same result.

SteveC
 
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