fk87 advice for a newbie.

[benlawrence]

Hi all just to give you a bit of background, we have an 82x94 motor here that we built last year, setup at 10.5-1 comp with cb 044 magnum plus heads 42 x 37mm valves deck set at 40 thou engle fk87 fully merged exhaust with stinger etc.

we ran this motor up on 44mm webers with 36mm vents, its all we had at the time, it made 150ftlbs torque and 146 bhp. we knew the carbs would be too small for this application but its all we had.

after a year of messing around doing a bit of racing and having loads of fun we decided to put crank fired ignition via ecu control, this was purely for the next build and wasnt put in place to improve performance throttle bodies were on the horizon for the superflo headed build, with the ecu (emerald k6) installed we ran it up (wasted spark) and yes it made exactly the same hp over the bog standard bosch 009 points and a blue coil give or take it was possible to run less timing to net the same peak horsepower but that was about it.

After a few meets we decided to put the jenvy throttle bodies on (45mm) and go full efi.

We ran these up and yep you guessed it, no gains!!

So where next?  i ported the heads and kept the intake to around 75cc.

We ran these up and made approx 15bhp, peak horsepower was at 5250 approx and held all the way to 7k rpm and beyond but does not climb from its peak at 5250. torque loss was negible.

So an improvement, however we are well short of horspower 158bhp, now this is where im scratching my head.

Rings were gapped up per spec, total seal 2nd etc, the only thing thats bugging me is possible valve float?

the 044's run the stock dual high rev springs that came with them, i spoke to matt (all torque) breifly last night and he agreed that float was possibly playing its part here and suggested that it was well undersprung for this cam, i thought this ages ago but we didnt adress the issue.

Sorry for the ramblings here, i'll be honest in the great world of performance vw's im just a beginner, we enjoy learning by our mistakes and like to learn as we go, ( there are no high performance acvw builders over here apart from a couple of formula vee guys)  so we are just getting stuck in, its fun, but a few pointers from "those who know" would be ace.

your thoughts would be greatly appreciated.

Thanks.

Ben.

[dannyboy]

i have a simular setup apart from 48mm cb throttle bodies and a dta ecu engine made 157fwhp  i had the heads ported to wedgeport pattern and it then made 174hp the dyno is a bit shy on numbers but all i can say is engine now goes much better  ;Dbest time is 11.8 n/a
dont underestimate the formula vee guys 

[benlawrence]

never underestimate a vee guy, one here is awesome very very clever man, but he's up to his head in the vee community and doesnt need someone like me bothering his head, we are talking flywheel horsepower here not wheel horsepower, the heads are wedgeported manifolds welded and matchported, the motor is coming apart after the last meet,on the 11th november, we have a set of jpm springs coming and will set them up, then run it back up on the rollers, after that its back to the drawing board. well, its on to different heads and compression, just trying to get the most out of what we have beforehand.

[Torben Alstrup]

I´d say there are most likely more than one reason to the rather low output.

1. The port volume is too large for a 42 mm valve. (Common mistake) Airspeed never comes up and get efficient. Therefore it drops off of the power before it becomes good. (Done that myself once or twice, until I figured out the relation between port volume and valve size) It is further underlined by the fact that it holds its power for about 1500 rpm.
Also the ports  - most likely have a bad shape somewhere, throwing the flow off a bit.
2. What header size ?
3. Are you sure the cam is set up correct ?

Since your ports are that large now, I suggest that you increase the intake side to 44 mm. and pay serius attention to the ports. Also maybe increase CR to 11-1. A 2275 in that set up should pull 200 hp.
T

[benlawrence]

Thanks for your input Torben, the heads were originally magnum plus's with cb's stock intake port out of the box, they made less power than they do now after my port work, stock they peaked at 5500 and power dipped very quickly from this point, now the power stays consistent from peak 5250 all the way and past 7k rpm so this is an improvement as the engine has 2k rpm more of available/useable peak horsepower, cam is dialled straight up no advance or retard, measured the lift at the valve last week, checks out fine.

[John Maher]

Ben, if the dyno figures are anywhere close to accurate you're losing a huge amount of power somewhere
As shown in the graph below, 44 IDFS are good for a lot more than 150bhp. The fact your upgrade to 45mm TBs made zero difference proves that. 45mm TBs will flow enough air for 260bhp n/a.

I finished a similar spec engine to yours recently - 2276cc, 44IDFs, 42 x 37.5 but with Engle FK10 instead of your FK87.
CR 9.5, 42mm CSP Python. Figures are at the flywheel, through the Python silencer (no cooling).



The fact you have peak power occur so early and then flatten off indicates a restrictive induction system.
The problem doesn't lie with the carbs or throttle bodies. I suspect the heads or manifolds. Or both!

[Fasterbrit]

That's a lovely power curve and peak power figure considering the relatively mild street orientated carbs. Interesting to see a slight stumble in the transition clearly defined on the torque curve. I bet you wouldn't even notice that on the street though. I bet that engine rips on the street, but is also very drivable. Great combo John.

[gizago]

Hi Ben, my engine sounds like a similar spec to yours, and was built for someone else by John a few years back and made 187 bhp on the dyno on 48 IDFs.

2276cc
 Engle FK87
 CB 044 Ultra Mag CNC ported 44x37.5
 1.4:1 rockers
 Webber 48 IDFs on CB Big Beef manifolds
Bosch 009 with compufire
 1 ¾  Merged header
10.7:1 c/r

Ive added IDA's and Mallory ignition but not had it dyno'd since but I assume it will be making a touch more now.

[benlawrence]

thanks for more input folks, the only thing we can compare to at present is a motor that was allegedly dyno'd in the states and possibly the uk? not sure, it was said to be a 200bhp motor (82 x 94), it dyno'd on the rollers we use at 178. 160 tq, 2276 51.5 ida's (alleged fk8) but im not so sure, power was well up at 7k rpm, steve tims heads. That was the old Phil French dkp car, maybe someone in the know could chime in on that spec.

I have no issue with the numbers, dynamics rollers are said to be on the lower end of the scale but are said to be more acurate, even if we were near 170 bhp i would have walked away happy ages ago.

Thank you john for your informative input, i would love to see how your numbers stack up on our rollers, but our track times seem to reflect the power being made, on this motor 13.7's around 96mph  with 2 sec plus 60 ft (146bhp), my old 2276 with less horsepower was making 1.9 60's and 13.8's. We havnt run on the track with the current setup (ported 044's with the jenveys, more bhp and more powerband) but we will hopefully find out on the 11th.

we'll pull the heads again and see if we can improve any more areas that need more work and re spring them, i would like to compression and leakdown the engine beforehand, John it just goes to show what you "hear" over the years doesnt tie up with what you get, I was always told 44's were only good for around 150bhp.  

I will stick my hand up and say that i know a little bit, but thats a huge difference from a "LOT" that you lounge guys have. We had a crank bar ground to replicate the crankshaft and we decked the case to the crank centreline and really paid attention on the bottom end of the motor and to which we've never had an issue, but top end we arre definately missing a trick, and i dont mind admitting it  

[John Maher]

Interesting to see a slight stumble in the transition clearly defined on the torque curve. I bet you wouldn't even notice that on the street though.

That torque dip is a common characteristic. The better the heads and intake system (high flow, good airspeed), the more pronounced it is. With a milder engine (smaller valves and ports, less bhp & torque per litre), the dip disappears and you have a smoother torque curve across the rpm range. As peak torque per litre increases, the torque dip appears - usually between 3000rpm and 4000rpm. It's exact position in the rpm range is influenced by induction and exhaust tuned lengths. In the deepest section of the trough, AFR goes over rich. On a carburetted engine there's little you can do. With mappable EFI you can dial out the richness and pull up the curve. It doesn't always eliminate the dip completely but will flatten it out.

I have no issue with the numbers, dynamics rollers are said to be on the lower end of the scale but are said to be more acurate, even if we were near 170 bhp i would have walked away happy ages ago.

Thank you john for your informative input, i would love to see how your numbers stack up on our rollers, but our track times seem to reflect the power being made, on this motor 13.7's around 96mph  with 2 sec plus 60 ft (146bhp), my old 2276 with less horsepower was making 1.9 60's and 13.8's. We havnt run on the track with the current setup (ported 044's with the jenveys, more bhp and more powerband) but we will hopefully find out on the 11th.

It's a tricky game comparing one person's set of dyno figures with another. For development purposes you should stick with the same piece of equipment and hope its calibration is consistent. A gain is a gain. Even if the dyno delivers conservative figures, the relatively low peak power rpm tells its own story. Track results are therealproof. It'll be interesting to see what ET and mph you come up with.

I was always told 44's were only good for around 150bhp

I used to think the same. It took me a while to discover the real potential of smaller street carbs eg 40 and 44IDFs. On a street engine I aim to use the smallest size valve, port, carb and exhaust primaries that will deliver the target power figure. Ports that are small, fast and efficient beat big lazy ports every time. For instance, 40IDFs are good for 150bhp+. Stick a set of 44s or larger on the same engine and you might make a few extra peak bhp but you'll lose out in the low and midrange.

[Fasterbrit]

John, what's the max hp you've pulled out of 45 Dell'ortos? Cheers, Matt

[tonybone]

Hi Ben.
What ratio are your rockers ?
What's the Venturi size in the jenvy 45 bodies?

I've run various different combinations on a similar motor and come up with some huge gains !

Tony

[Torben Alstrup]

What John said. I did´nt think of the manifolds. Good thinking.

T

[John Maher]

John, what's the max hp you've pulled out of 45 Dell'ortos? Cheers, Matt

Can't remember when I last used a set of 45 DRLAs.... must be at least 15 years ago!
Back then I was probably in the mindset they were only good for 150bhp max and as a result I never tried a combination that tested their full potential.
In the intervening years I've discovered I have a lot to learn!

The 2276cc 44IDF graph I posted earlier in this thread came as a pleasant surprise - I was expecting around 165bhp based on pre-build calculations.

It's only a guess but I reckon a pair of 45 Dellortos are probably good for 190bhp with the right heads, CR and cam etc. DRLAs are great carbs for performance street motors. It's a shame they're no longer available.

[Shane Noone]

Hi Ben,

Just reading your thread. So you initially made 146 bhp on the 44 carbs with 36 vents. Then switched to 45MM throttle bodies and gained 15 bhp so that takes you to 161 bhp. You already know the dyno dynamins chassis dyno is tight so let's add 18 bhp to compare more closely with John's stuska dyno figures which takes us to  179 bhp.....now we are starting to get in the range of where most motors with a spec like yours fall, ie 180 - 200 bhp at the flywheel no cooling. If your figures from the chassis dyno are flywheel estimated it is at least comparing like for like. Also if you ran with your fanbelt aka cooling in place then you can normally add another 15 bhp at least to your total figure giving around 194 bhp. This is bang on the money my friend for your motor spec ! 

Cheers

Shane.

[benlawrence]

Hi Ben,

Just reading your thread. So you initially made 146 bhp on the 44 carbs with 36 vents. Then switched to 45MM throttle bodies and gained 15 bhp so that takes you to 161 bhp. You already know the dyno dynamins chassis dyno is tight so let's add 18 bhp to compare more closely with John's stuska dyno figures which takes us to  179 bhp.....now we are starting to get in the range of where most motors with a spec like yours fall, ie 180 - 200 bhp at the flywheel no cooling. If your figures from the chassis dyno are flywheel estimated it is at least comparing like for like. Also if you ran with your fanbelt aka cooling in place then you can normally add another 15 bhp at least to your total figure giving around 194 bhp. This is bang on the money my friend for your motor spec !  

Cheers

Shane.

Shane i see your point , but its one of those arguments that goes round and round guesstimating what an engine will make on another dyno isnt relevant just to make the numbers up, john is right that in order to see gains (or losses) you must keep with the dyno you use, the rollers we use are excellent and repeatability is spot on and our dyno guys go above and beyond to help us try and extract the last "nth" from what we have.

As i mentioned shane i think the track times back up our power figures, my old 2276 dyno'd at 135.5, i ran 13.8's @ 94 (all steel car), The engine we are discussing in a very similar weight car has run 13.7 @ 96 in 146bhp tune.

I think these times stack up fine, bare in mind 4th gear does need changing to a lower ratio.

The proof is in the eating and the Phil French dkp car proves that 180bhp out of a 2276  motor has run on these rollers (through the muffler belt on), we are just trying to get the numbers up (not an easy game, and if it was, we'd all be doing it right  )

John may well be right about restriction in flow on the heads or manifolds and its something we need to look into further, if the new springs turn up this week then we will pull the heads off and i can look into the heads again, we welded and ported the manifolds right up so i have my doubts on them being an issue but we will see.

We played around with trumpet lengths in the search for horsepower, but all that did was shift the power band.

The track will let us know if the small gains have done anything, weather permitting we should be out on sunday!!

Its turned into an interesting thread, and i thank you folks for your input (again) it is well appreciated.

[Simpsonshoe]

While, no doubt, you are not making the power you want, you don't say what you car and driver combo weighs. ET and MPH are all about pounds per horsepwer..You said "all steel" yes.. but what does it weigh? A '56 weighs over a hundred pounds less than a '68...And how much does the driver weigh? It all adds up.. take a typical 1750 pound combo.. car and driver. A well set up car with 150 HP should run about 12.70 at around 103... Add that ICE and sound insul and bumpers and such..say 150 pounds?   Well, now you are looking at 13. ohs...at 101...so 1900/ 136 should be about 13.50.. add in the fact that you have the wrong gearset and 13.70-13.80 is realistic..If you are running about96- 97 mph then the numbers add up..135.5 on the dyno is not always what you get at the track also....It is good that you included MPH figures because that is the true indication of HP.. tune for MPH and get the chassis/gearing to work.REMEMBER.. the power is in the heads.. but everything has to work as a team...Good luck.. 

[benlawrence]

Well it was a beautiful morning today ( although frosty) we arrived at 11 and the track was still greasy, I played tea boy and helped Dave out, first run lit the tyres waste of a run, 2nd run same track still too greasy. 3 rd run was going well till he missed 3rd gear. 4 th  run he lost all the gears. We pulled the motor only to find the brand new daiken super disk shredded to bits on the pressure plate side.  So that was the end of that first season, but what a great time it's been, . Would have been nice to get some numbers from today and im sure we would have made a slight improvement, dave said it was pulling a lot harder in 3rd now until the clutch let go. but by the time we left for home the track had dried and there was plenty of rubber down , hey ho, roll on nights in the workshop over winter

[benlawrence]

spot the daiken, "not so super" disk!!! 

[andy198712]

ouch!

[rick m]

I would recommend contacting Art Thraen in Salt Lake City, Utah, for one of his copper head clutch discs.  I have used them on my motors since he developed them. He ran them in his street and race car.  They work with a good pressure plate. I just re-installed the one that was in my 2275 because the flywheel and the disc were still good after 3500 miles of relatively fun use! :-)

Rick M

His link is listed below to look up the disc.  Scroll down on the products page when you load the page on your website.

http://www.aircooledengineering.com/products.htm

[richie]

spot the daiken, "not so super" disk!!! 

Hi Ben,

 where did you buy that disc from? there are some cheap copies out there being sold as the real deal and they are sh*te, we have used alot of the real ones and not had any problems, getting down into the 10s with one with a stage 2 cover in dannyboys car

Anyway glad to see you are having fun over their

cheers richie

[rick m]

Richie,

Art Thraen of ACE VW. He is on the web.  I have run his disc since he brought them out. I drove his car which is what originally sold me on the disc.  Not sure it would work on your turbo car. You'd have to ask Art.  With a stage 2 or 3 pressure plate it might do well. I use a stage one on my street car and it hooks the tires up fine.

Rick M

[benlawrence]

spot the daiken, "not so super" disk!!! 

Hi Ben,

 where did you buy that disc from? there are some cheap copies out there being sold as the real deal and they are sh*te, we have used alot of the real ones and not had any problems, getting down into the 10s with one with a stage 2 cover in dannyboys car

Anyway glad to see you are having fun over their

cheers richie

Hi Ritchie, the disk came from Jim Calvert so i doubt its a spurious one but i guess you never know, theres a jaycee puck sitting on the shelf so that may end up being pressed into service, clutch adjustment was spot on, you never know what it could be down to, maybe driving style, 2 disks destroyed from the last two meets, the phil french car ate its disk as well, I run a stage 2 plate with a cheap cush loc disk, and i have never had an issue  all season??? 

Rick, thanks for the heads up on the disk from Art, Britt has offered to pick one up when he's passing through 

[richie]

Weird, you would allow for one failure and put it down to "sh£t happens" but 2 seems a little strange,was this in the same car with the same driver?same clutch cover?
both from Jim I pressume? maybe he got sold some copies by a wholesaler, if you go to a puck your gearbox will not thank you

cheers richie

[benlawrence]

i was thinking exactly the same r.e the puck rich 

we had 2 cush locs shred, but one car was driven by 2 different drivers on the day it went plus a few good dry burnouts, so my guess is that it just took too much abuse.
the other one went on the same day.
I get the feeling it could be down to driving style, on the first run the clutch was stinking.

[dannyboy]

as richie said i have been hammering the crap out of my daikin disc with a stage 2 plate i reckon the best part of 280-300fwhp when on the gas i have no slip and have had over 40 passes onthe current one good disc and hopefully its saving my box from a nasty end 

[benlawrence]

Its all part of the fun being total amatures at this racing lark  

that was a cush loc 

[dannyboy]

Its all part of the fun being total amatures at this racing lark  

that was a cush loc 

i had exactly the same with a cushlock without gas the daikins ihave used have worked a treat
the fun must be a major part of it banter is important 

[benlawrence]

Ha ha yep we sure do have some banter, i get accused of going early  where as i acuse my mate of being bagpuss as he always seems to be asleep when the lights drop.

If anything, it has been a right good laugh for a first season and driving around ireland trying out iffy dragstrips with weeds growing through them has been comedy,  i hope it carries on that way, I have no aspirations of going seriously quick (doesnt everyone say that!!!!)  anyway, i could even if i wanted to, the mrs wants a kitchen!!!!