nick_m

cant believe this is the same car

Hytech exhausts stand by that pairing as well. It sequential pairing related to firing order. So both exhausts pulse go out one collector instead of each collector. It's definitely the minority but hytech make some of the best Honda and Atlantic headers on the market. So there must be something in it i guess. Hit me up on pm with some engine and cam specs and I can give you some specs if you want to try a 4-2-1. Looking at Rhys headers I'd expect to end up with similar sort of dimensions with the way I spec them which is encouraging as Harris are much cleverer than I am.

Hey rhyscar. That's very interesting. I haven't done a lot of 4-2-1 but when I have I spec the first collector length at peak hp and the second collector at peak torque or sometimes under depending on engine use. And the choke diameter for the peak torque becomes the secondary runner diameter and the choke for peak hp becomes the second collector choke. Seems to give good results but unsure if that's the "correct" way to spec them never tested vs 4-1 headers directly tho. Interesting that your megaphone is so far from the final collector. How did you spec that? I haven't played with stepped headers tho am aware of the merits. Just a hard sell for most customers. Would build on my own personal headers. My headers I only get one shot at unfortunately. Would love to do some actual header testing. But would be very time consuming. Out of interest who do you use for your cams? Cheers nick

the atlntic headers may well have been 1.625" now that I think about it, it was a while ago I did them, I think for your setup youre better sticking with your 1.5" primaries over the 1.75" but yeah it would be interesting to see the results of the collector testing. I reckon cones/megaphones off the collector is the go, well at least ive always had good results anyway. I'm far from an expert and definitely haven't done any where near the amount of exhaust testing on a single motor that you have. Maybe start with a 2" choke and work up from there. I know that specifically with SR20VE motors most of them lost power in a big way when choke sizes went over 2.25" so a 4age would probably be happy with something fairly close to 2" the atlantic I went slightly bigger as it obviously has the gearing to keep the power in a 1200 rpm window and they were spinning to 9. We also did the tuned primary length at 7500 as this was the lowest rpm it dropped too on gear changes. This made it a lot more driveable too according to the driver. Its all just a half educated guess at the end of the day, at least you have done a heap of testing so have a decent amount of data to work from. look forward to seeing how you get on

id be trying a bit more exhaust stuff, I have a hunch the collector is too big/steep angle. Specs i built for a formula atlantic car, 22" primaries 1.75: dia, 12deg merge collector (15 deg would have been nicer but autobend collectors are 12 and easy to get), 2.25"OD choke with 300mm long cone/megaphone to 3" diameter, then a 2" long reverse cone back to 2.5". had a short 2.5" exhaust/muffler combo being at open wheeler. It woke it up a shitload compared to the 2" primary short runner/steep angle collector straight to 2.5"exhaust that came off it, the owner said it was an entirely different car. id probably run primaries around 24" x 1.625" OD with just an autobend merge collector - just clean the insides a bit with a sanding roll. id go for a choke a sniff under 2.25", say about 54mm and do a 54-63mm 300mm cone/megaphone. would be interesting to see how much difference just changing the collector setup to the above would change it (I assume your running 1.75" primaries) Exhaust stuff is tricky tho I'm pretty sure its some kind of black magic

Like that collector,looks bloody good Did you buy the bends from somewhere for the merge part of the collector? what angle are they?

Hey what size is the turbo drain hose. 5/8 and how long? I might have an off cut of the proper stuff at work you can have

That sucks about your dog man. Really sorry to hear. Looks like the car is progressing well. If you need a crew member for the ashburton street sprint let me know! Haha

Yeah plus one on a stainless flexi. Will save you the head ache later

Ha that was a night full of many big bourbons! I like those throttle bodies they look great!

Glad you're stoked buddy. I love this car. Was awesome to get to do a proper all out cage with all the gussets and fun stuff

Oh OK na heaps of room for that. Cool man. Glad you like it. Its a fucking cool car you've done an awesome job on it

Yeah he did. I've got your email at work. You can see harness bar here. Its between rear stays about 30mm up the stay from the strut tower. So you should be room to be able to get a firewall either side of the strut tower I wasn't 100% clear wgich side of strut you wanted to do the firewall so left enough room for either. That all good?

Oh also do you want those bits of sound deadening removed? I can have a go when I drop the cage. Doubt you'll stand a chance once it's fully welded

Making a start on your cage. Pretty happy with how its coming along. Got it fitting pretty good. That's a piece of card slipped between roof skin and roof diagonal