Redline Intake Manifolds

[kangaroosa]

aHH JESUS - I finally make up my mind and a whole heap of other offers get thrown up. LOL - Just kidding guys.

 

I don't want to spend big dollars on a twin carb setup - which basically rules out any twin side draft carb setup. So i can scratch that idea from the list.

I'd be happy with a single side draft that is nice to drive and does the job.

 

Xany is most welcome to the Dellorto's - I have been told that parts for Dellorto's are either to expensive or few and far between, compared to weber's. (But thats only one dyno shops opinion).

 

The Dyno shop i was reccommened is "Rank Rotary" in Moorabbin, VIC. As the name says, they specialize in rotaries (and bloody quick ones at that), and they are also well known for being experts in Weber tuning (thats not my opinion-hehe).

 

The engine was built by an engine shop and they assured me that the boss had this combo in his car years ago, and it flew. The cam is actually bigger than planned. The first cam was more mild but it took a lobe off and killed a lifter during the first 10mins of it life (strange, but the exhaust lobe on cyl 3 was actually offset by half a lobe when u look down the lifter bore). So they replaced the cam with a speedway grind from memory (don't ask me why). Yes its a road car and at the moment its very driveable - I actually think my 4k was more lopey than my 5k. I used to get at least 1 person a week pull up next to me at the lights and ask if i had a Rotary in it.

 

As for the glazed rings - Many people tend to agree with the theory that if your carb is running waaaay rich, then the excessive petrol washes the oil off your bores and glazes up your rings.

I had this carb on my 4K and had no drama's - I also had Chrome Molley rings in it for 4 years and to this day it never used one drop of oil and had 165ish PSI on all the pots. I've had nothing but trouble with this 5K.

 

56rwkw doesnt seem alot to me, That equates to 75rwhp. 15%-17% loss in power through drive train with a manual, so roughly = 88-90hp at the flywheel (did i do the maths right? Please don't bag me too much if i'm waaay of the mark here).

I'll include the dyno sheet from the original run that diagnosed it as running rich.

Also included will be the cam specs for TRD.

[kangaroosa]

The lower lines are the air/fuel ratio's for the two runs. I'm told that the line should be straight (horizontally) and up around the 14 region. The HUGE drop off is where its runs waaay rich. They tried a standard Aisan carb to test whether it was due to carburation or cam related. The standard Aisan had the same results and so they reckon its cam related (not making enough vaccuum in a 1000rpm range). The program only prints out figures as low as 10 AFR:P, but the screen showed the weber dropped right down to 6 on the graph. Although there was never a hesitation or flatspot with the weber - It went like stink, but the oil usage and the plumes of black smoke when booted it prompted me to investigate further and thats what i found....too rich.

ATM i have a rejetted aisan which goes ok - but not as good as the weber.

[kangaroosa]

The RPM thingy wasnt hooked up, so ignore the RPM figures.

I know it was run in 4th gear at a max speed of 134km/h.

As i said before, the air/fuel ratio shows a reading of 10 in some areas - It was actually still dropping to a min of 6, but the program doesnt print it that low.

[kangaroosa]

The cam specs for TRD.

[TRD ke70]

I also had Chrome Molley rings in it for 4 years and to this day it never used one drop of oil and had 165ish PSI on all the pots.

reading everthing you're got there, i think the cam is way to big for a street engine.

 

i know they can sound good when idling but they produce f@$k all torque and power.

 

i your case, i think the cam is starting to come on just as your webber runs out of flow, this would be why your making only 56kw's.

 

just a little info for you, no one makes chrome moly rings, you can get chrome rings and you can get moly rings, but you can't get chrome moly rings.

 

the moly rings are cast with a moly insert.

 

as for it glazing up the bores, there's a million reasons, from the wrong oil when running it in, to the way you drive it. but at the end of the day you'll have to strip the engine and deglaze the bores to fix the problem.

some where in the posts there is a link to a site about running your engine in, read it, it's really quite true.

 

i think if you put a single side draught on with a smaller cam you'd make better power and torque.

 

but this is my opinion only.but it does come from f@$king around with these engines since 1988, in both Competition and road engines.

 

good luck and i hope you get it sorted.

[kangaroosa]

just a little info for you, no one makes chrome moly rings, you can get chrome rings and you can get moly rings, but you can't get chrome moly rings.

the moly rings are cast with a moly insert.

 

 

i think if you put a single side draught on with a smaller cam you'd make better power and torque.

 

but this is my opinion only.but it does come from f@$king around with these engines since 1988, in both Competition and road engines.

I just remember purchasing the rings years ago and for some reason chrome molley seemed very familiar - it definately had molley in the name somewhere. They must have been just molley then. Maybe i'm thinking of push bike frames or something... hrmm i dunno.

 

I definately going with a single side draft - That has been decided.

As for the smaller cam - I'll might get the engine engine builder to see what he can do when when i drop off the engine for him to fix the rings.

When you say a smaller cam - You mean smaller lift? Different advertised timing?

I love the sound of a Lopey engine and preferably don't want to lose that. I don't know all the technical stuff about cams but the engine builder said that the cam should work from 2500RPM up to 5500RPM.

 

I appreciate anyones opinion on here - especially the people that have rooted around with these engines for many years.

I was comparing my cam to the tighe cam grinds, and nothing is even similar to mine. That is just by comparing valve opening times.

I assume my cam is up the "Race" end of the scale as far as cams go.

[Redwarf]

That is a HUGE lift cam, and probably something I would only consider for track. Have a word with Wade cams (I think they're in Oakliegh now), they used to do some really nice Corolla grinds. For street I would consider something around the .400" to 420" lift mark, maybe even smaller. FWIW my 3K engine has just over .430" lift, and it makes around the 65kw ATW mark with Webers.

[kangaroosa]

That is a HUGE lift cam, and probably something I would only consider for track. Have a word with Wade cams (I think they're in Oakliegh now), they used to do some really nice Corolla grinds. For street I would consider something around the .400" to 420" lift mark, maybe even smaller. FWIW my 3K engine has just over .430" lift, and it makes around the 65kw ATW mark with Webers.

Yeah i'm not quiet sure why the engine builder picked such a big cam.

Now is it possible to regrind my existing cam back to a smaller cam profile - i would imagine it depends on how much meat is left on the lobes... right?

 

65rwkw - you got yourself a little rocket there. Well if your getting that out of a 3K setup for racing.......i would be hoping to get a bit more than from my 5K right?

Edited April 23, 2005 by kangaroosa

[Redwarf]

Yeah i'm not quiet sure why the engine builder picked such a big cam.

Now is it possible to regrind my existing cam back to a smaller cam profile - i would imagine it depends on how much meat is left on the lobes... right?

 

65rwkw - you got yourself a little rocket there. Well if your getting that out of a 3K setup for racing.......i would be hoping to get a bit more than from my 5K right?

It does have a certain amount of stick. :P There is still more in it, but the drivetrain has enough issues as it is.

 

Just grab another cam from somewhere and take it to Wade (or whoever). your current one would be no good for a regrind. Cams grow on trees, and it shouldn't cost more than $100 for a good regrind.

 

I'd start off by giving Wade's a call on Tuesday.

 

Cheers

 

R

[Super Jamie]

i personally think that's a pretty good cam profile, and if your valve springs can handle that much lift without bouncing then stick with it. it's a little bigger than the tighe stage 3 grind, which is mine and nick's favorite. your cam's only a 272 degree cam, it's not very big at all, i'd say it's about just right for a 4k/5k

 

ideal AFR is 14.7 for max efficiency, and 12.5 for max power. i think your car runs rich down low in that dyno graph because the primary choke is too big. changing back to a standard aisan is no way to diagnose problems, they run rich anyway and are shithouse at atomising fuel. sounds like you need a new workshop. or twin sidedrafts :P

 

the single dcoe would probably be an improvement over whatever you have at the moment, even if just for driveability. but i don't think it will be that much of an improvement. look at it this way, you'd spend 700 bucks and have a small improvement, or spend 1500 bucks and have almost perfect carburetion. sure it costs less, but where's the best value for money?

 

i agree 56rwkw is pretty low for a 5k, stewart's 4k makes 53rwkw. he's using a camtech 609 (In 33-64 Ex 72-32 Lift 0.435). consider rob's engine a 4k, and a pretty oversize 1430cc one at that :D

 

you usually take 25% for rwd drivetrain losses. or just convert engine kw to rwhp (which is *0.746). 100kw at the engine = ~100hp at the wheels

[kangaroosa]

I've got brand new dual valve springs fitted, so there is no problem with valve bounce.

So if i went down the side draft path, Who can reccommend a decent fuel pump and regulator that is both affordable and reliable.

 

OK - So the only thing worying me now is the varying opinions on fuel efficiency.

I know the Redwrf has always got his right foot through the firewall, so obviously the car is going to drink. But then people say if i drive it normally it should be fine - which i tend to agree with. Wouldnt anyone care to enlighten me on what fuel consumtion i should expect to get with twins (driving around town). I used to get 10km/L from my untuned weber.

 

P.S - I will be finding another workshop. A car shouldn't go in untuned with 56rwkw and comes out tuned with "48ish" rwkw. It just doesn't make sense to me.

[Super Jamie]

go into any decent tuning shop and get a little facet fuel pump and an adjustable dial pressure regulator. you should walk away no more than $150 lighter

 

it's said that with dual sidedrafts, you can see the fuel gauge going down :P maybe on a rotary, but i wouldn't be expecting any better than 8L/100km at least. christ, even a downdraft weber can be worse than that if you want it to be

 

i'm going out on a limb here - forget sidedrafts. i had a pair of dellortos, and i found them too expensive to bother with, so i gave them to rob, who spent $550 (?) reconditioning them. sure it's going to be a bit more expensive if you buy new carbs and new manifold, if you look for long enough you'll find some which require not much work, and a second hand manifold (i bought my twin sidedraft manifold for $120). you sound like you don't want to spend a heap of money but still want a decent setup with as little compromises as possible. like me :D

 

learning about SUs the last couple of weeks, and having mine partially apart, made me think how the most simple solution (one needle, one jet, one adjustment nut) is often the best. i would go as far as to say the last 100 years of people fartassing around with venturii and air jets and emulsion tubes was a complete and utter waste of time and effort. george skinner had it right back in 1905 with the SU carb. with a downdraft/sidedraft you tune the car in using jets and tubes until you find two ideal points which your car lies between. an SU is totally "analog" in its tuning, you adjust the thickness of the needle to suit the car, so you can potentially obtain a near-perfect tune, moreso than you can with a carb that uses e-tubes

 

i reckon, if you can find a pair of SUs on the cheap, you could buy a new manifold and still have them tuned and on the car for as much, or less, than a single dcoe

 

 

your workshop sound like idiots, they run a car at ideal power AFR on its run in, then tune it back to stoich after it's run in. most workshops run a WAY rich run-in tune, and if an engine's pretty off its tits (like yours is) run it slightly rich on its' final tune. i've never seen a rich engine glaze rings, and i've seen a few built and tuned. mine runs rich as all buggery, and i've had the head off and the bores are spot on

[Redwarf]

Jamie, it's only 1360cc. :P

[kangaroosa]

I just had a thought - A bloke i work with owns an Alfa Romeo. They run downdraft and sidedraft webers standard (depending on the year and model). I visited his spare parts bloke a few weeks ago and priced a a single DGV weber at $120.

I should go back and see what price he's willing to part with 2 sidedrafts.

The alfa sud's came in a 1.7L motor, so you would imagine that the carb is somewhere close to what i need.

[Super Jamie]

cheap parts, much better :P

 

1360cc my bad :D rob, did you have to re-choke those dellortos you got off me? they were originally on a alfa 105 gtv, 2 litre

 

ps: i'm chasing some cheap SUs from a 5k for you, the dude's getting back to me

Edited April 24, 2005 by Super Jamie