LordWorm build commences...sort of

[niky]

I saw one guy do ITBs on the older (non-VICS) FSDE... same thing, Black top items... said that tuning them was a pain (took six months to get it working).

Well, you don't have to go for the perfect build... just get as close as you can within the limits of your engine bay.

BTW, I need an opinion... 3" collector or will 2.5" do? I'm thinking of about 24-26" 1.75" primaries for my headers... of course, my goals are a bit more modest than yours... ...probably won't need as much pipe.

 

[LordWorm]

I saw one guy do ITBs on the older (non-VICS) FSDE... same thing, Black top items... said that tuning them was a pain (took six months to get it working).

Well, you don't have to go for the perfect build... just get as close as you can within the limits of your engine bay.

BTW, I need an opinion... 3" collector or will 2.5" do? I'm thinking of about 24-26" 1.75" primaries for my headers... of course, my goals are a bit more modest than yours... ...probably won't need as much pipe.

what sort of header you building? and what is your source for the numbers?

Basically, if you are building a merge collector, you want it to collect at an angle of 15 degrees (you can go more agressive than this angle, but 15 degrees makes manufacturing nicer, and broadens your powerband somewhat...)

3" collector is massive overkill. basically at the end of your collector, you want the diameter of the rest of your exhaust system (you don't want to reduce back down again, and waste all the velocity you've built through the collector)... so if its a 2.25in exhaust, 2.25in should be your final collector cone diameter.

I'm chosing a 2.5in exhaust system for my car so my collectors final diameter will be 2.5in. As for how far you "choke" the collector down before transitioning to your final diameter, thats a bit of an unknown... i'm experimenting with a few collectors... i'll let you know how it all goes.

quads are a complete pain.. Painful on your ears too. And from what i an gather, the ram tunnel will generate more usable power for a daily driven street machine. Time will tell though, i still have the quads - so i may yet try and do something with them, even if its just an experiment.

 

[Kooldino]

Another update - Well the bolt extractor didn't do the trick In the end there wasn't enough meat on the nut for it to grip on to and it just chewed the thing to pieces.

What? Geez.

Ended up grinding it off. No idea how, or indeed if, I will replace the 3rd mount stud.

Drill it out and use a bolt if you have to, but I think it's important.

Another problem i've got is measuring the distance from the centre of the intake valves to the centre of the port they belong to. This distance makes up part of the runner (so with 20in runners, if the distance from port to valve is 3 inches, i only need 17in runners from the port to the opening of the velocity stack....). Kinda hoping Kooldino has a head off a car right now and can measure this for me

I might be able to get you the distance from the valve stem to the outside of the port this week.

anyway, attached are some runner calcs I've done. This first set of 3 calculations is done tuning the 2nd reflection to around 8000rpm to get a runner length, and then working out where all the other reflections occur.

Why such a high rpm?

 

[LordWorm]

What? Geez.

I know! crazy stuff...

Drill it out and use a bolt if you have to, but I think it's important.

how hard would that be? it looks as though the rear mount is sitting on an enclosed box....wondering how hard it would be to get a bolt up in there?

I might be able to get you the distance from the valve stem to the outside of the port this week.

That'd be awesome....

Why such a high rpm?

In preparation for my engine build next year - which will involve shortening the stoke and going north of 9k....Theres little point having the thing kick at low RPM When all the rev range i use at the track is high.....

 

[niky]

Okay... 2.25" it is, then. Kinda thought 3" was weird. I'm just looking through various online-calcs and trying to get an idea. Taking business math and trying to learn header-physics at the same time is a headache. :lol:

15 degree angle? This is the angle of the neck-down?

 

[LordWorm]

Okay... 2.25" it is, then. Kinda thought 3" was weird. I'm just looking through various online-calcs and trying to get an idea. Taking business math and trying to learn header-physics at the same time is a headache. :lol:

15 degree angle? This is the angle of the neck-down?

the angle at which the pipes "merge"

go find me a picture, and i'll point out what i mean

 

[Kooldino]

I know! crazy stuff...


how hard would that be? it looks as though the rear mount is sitting on an enclosed box....wondering how hard it would be to get a bolt up in there?

Ah, true...I think it might sit on the subframe tubing. Tough to recall exactly.

In preparation for my engine build next year - which will involve shortening the stoke and going north of 9k....Theres little point having the thing kick at low RPM When all the rev range i use at the track is high.....

9K? Good lord.

 

[LordWorm]

9K? Good lord.

i gotta get my kicks somewhere I don't have a snail so RPM is where its at

 

[LordWorm]

Bit of an update (i know, this is less of a build thread and more of a talk fest...but interesting conversation none the less!)

My mounts should be finished today, and i'll get them reinstalled as soon as i've got them back. 95duro solid filled mounts - good luck breaking these!

on the IM side of things....

I've reworked the equations and come up with the following ideal runner length. Somewhat around the 19in area... results are:
2nd wave: 8524 rpm
3rd wave: 5711 rpm
4th wave: 4283 rpm
5th wave: 3426 rpm
6th wave: 2844 rpm

I've juggled the effective valve closed duration correction factor a bit to get these runners down to something sensible. This assumes a wave speed of 1300f/sec. If i can cool the intake charge down enough, and get the wave speed down to something like 1250f/sec, my waves occur something like 400rpm earlier on average. Speed of sound is related to the density of air, which is related to the temperature. Lower the temperature, the denser the air, the slower the waves move, which brings everything down to a more usable RPM.

Reason i've gone for 19in runners is that it gives me waves 3 through 6 right now, and gives me wave 2 when i rebuild the engine for ballistic RPM. its a great future proofing exersize. The ACTUAL length of the runners will be dependent on the distance from the valve to the port, which Kooldino is finding for me.

If i can, i'm going to go with straight runners, dead straight - with a taper to further amplify the pressure wave effect.

Plenum volume is now the only thing I need to work out. i'm considering going for a slightly larger than needed plenum to further enhance some midrange and keep the thing street drivable.

 

[niky]

the angle at which the pipes "merge"

go find me a picture, and i'll point out what i mean

Oh... no need... I get it... sorry... last off-topic post... can't wait to see what you get with your build.

 

[LordWorm]

New mounts are in.... 80 duro they went for... but solid filled - they aint tearing... no way known.

Had a quick measure up in the engine bay for the intake mani - 2nd order resonance is going to be rather difficult to accomplish given the space.

I've settled on 19.0in runners, and have estimated distance from valve stem to port to be 2.5in (Kooldino to confirm for me) - this means that the runner length from the port opening to the tip of the air horn needs to be 16.5in. I've only got about 13in until i'm bang up against the firewall, and then i need to fit the plenum in.

I can go for 3rd order resonance, and cut the length down considerably - maintaining straight runners with a taper - or i can go as far as i can go with a tapered straight runner, and then bend over the top of and into the back of the plenum with a donut... It wont be ideal because the taper doesn't run the whole length of the runner, but i figure some taper is better than no taper at all.

Problem is going to be fabricating. To make it look like something that isn't ugly, i'm going to have to weld the donut to the plenum, or at the very least, make the plenum sit flush up against the curved part of the runners. This limits my plenum bore size to the diameter of the donut on the inside. Problems with this will be: not enough clearence of runners to the top of the plenum (needs to be about 2in)...OR if too big, overall plenum volume will be miles too high. *grr*

I'll keep pottering away with the geometry...*sigh*

 

[LordWorm]

new mounts all in. Makes a car with 95 duro AWR mounts and inserts feel like a limo if you compare the vibrations.... its BAD... you can't talk to the person next to you while it idles, without your voice shaking.

The wife = not impressed... but she'll live.

Did some microtech rewiring today to tidy a few things up, tightened up any bolt i could see and got rid of some rattles, and just got back upstairs from starting to reinstall/fix the interior.

All in all a good days work.

IM - got a quote on my tapered runners, a little scary, but i'll ring a few more places and get some other quotes.

 

[Greensleeper]

Lordworm, how can you extract such high rpm out of our engines? Custom crankshaft and longer rods/custom pistons? Or just long rods/custom pistons?

(Sorry if I missed a thing or rwo, I have read almost all of the posts... and I read the one's with crazy calculations diagonaly lol).

Thanx!

 

[MakeMeGoFast]

Have you thought about a Dry sump oil system.......lol. Would help with the high RPMs since there will be no parasitic loss when the crank hits the oil.

 

[LordWorm]

Lordworm, how can you extract such high rpm out of our engines? Custom crankshaft and longer rods/custom pistons? Or just long rods/custom pistons?

(Sorry if I missed a thing or rwo, I have read almost all of the posts... and I read the one's with crazy calculations diagonaly lol).

Thanx!

Long rods + stock crank will get up around the 8500rpm mark fairly easilly. 8750 is doable but apparently the motor "wont like it". By long rods i mean custom things - none of the long rod kits that are available will support that kind of RPM.

To go further, you need to shorten the stroke - i'm hoping the FP crankshaft will fit, then bore back to 2L. I'll sacrifice a fair slug of torque doing this - but torque is for pulling caravans, not cutting great quarter mile times if the FP crank fits, i can get a 1.7:1 rod ratio, which will be more than ample for north of 9k.

Problem with such high RPM is that the piston speeds (which are a function of the stroke), even on a short stroke, get WAY out of control, and on pump gas, the pistons will actually outrun the flame front. so for daily driving i'll have to wind it down to about 8500, then run race gas at the track for the big RPM.

Its a little way off, i don't have the $6k i need to build the motor just yet. So i'll be doing all the supporting mods first.

MakeMeGoFast: drysump has been considered, but i'll probably just go with a custom baffled wet sump with windage tray/crank scraper and a crank case evacuation pump

 

[Greensleeper]

Thanx for the great explanation Lordworm!

 

[Kooldino]

Here's some pics of a "mock up" setup that was tested awhile back. It's just a thin metal "plenum" and a single tapered runner that we were just getting some flowbench numbers on...

(edit - the last pic is of one of our stage 2 heads with stainless steel valves)

Oh, worm...also measured the intake port length for you. I can't recall...it was either 2 5/8" or 3 5/8".

 

[LordWorm]

Thanks man! those mockups look great. I've sent you a PM with some more info that i've gathered...

damn i should get you to make my head... i need 5 angle valve job, welded and reshaped combustion chamber (cloverleaf/pent roof for the win!) and a few other tricks done
hehe

 

[Kooldino]

Reshape the chamber, eh? That could be tricky. There's not a lot of room to play with that's not already consumed by the valves. Boo for small bore. I'd be happy to see a SpeedCircuit head on your motor, but I suspect international shipping will **** you.

 

[LordWorm]

Reshape the chamber, eh? That could be tricky. There's not a lot of room to play with that's not already consumed by the valves. Boo for small bore. I'd be happy to see a SpeedCircuit head on your motor, but I suspect international shipping will **** you.

Yeah most certainly. I remember helping Twilightprotege ship cams to the states....cams weigh nothing next to a head - and the cost was astronomical.

Another prob would be i'd be without a car for a considerable amount of time (shipping my head to there, getting it shipped back etc)

The guys who i'm going to use to rebuild my motor (they build pro stock drag motors, and stock car race engines, as well as some touring car engines) reckon they can get a pent roof or cloverleaf in there, and i know Installshield managed to do it...I'm just concerned about what is sacrificed to get it to fit (i don't want to gain masses of combustion power, if it means i have to sacrifice flow - sort of a case of robbing peter to pay paul if i do it that way....). But i'll leave it to the experts when it comes to head work.. if my builder says it will be best, i shall trust him.

Yeah our bore sucks.. Big time. people just don't get how much stuff it limits. Rod length is limited because if you to too long you end up hitting the cylinder walls, you can't get much overbore out of it, even if you sleeve to make up for having very skinny walls, you get ZERO room in the head, you can't oversize valves (well, maybe you could by 1mm or something...wow..).... All because of the stupid small bore/short motor design....
*grumble*

we should have all gotten FE3's instead