A15 Build: Needing Tips on Machine Work

[Kirden]

I am planning a mild build for my B210's A15. I have a bogg brother's manifold and kirk racing headers so I know that I will be port matching the head, but what other head work is important for the best flow on a street build? I will be boosting my setup in the future (M45 supercharger and yamaha R1 Boost Box), so while I'm rebuilding the engine, should I worry about increasing valve size?

I also plan to contact Delta Cams to have my cam reground, but I'm not looking for a high revving engine. This will be a quick street car with very little to no track time. Do you guys have any tips on a proper grind for street use (staying around 6-6.5k max rpm) with higher exhaust duration for superchrging?

[RedBanner]

Oh man. Well, I guess id start by asking wich head you have. There are so many desighns for the a series.

[Kirden]

Wow I feel like a dolt. I submitted this post once and got kicked out so I quickly wrote back what I could remember and forgot the head type...

I have an H89 head. Oval port "closed chamber"

[RedBanner]

Then you already have the biggest stock valves. I think your set man. Valve springs are a great upgrade for a series motors, and so is a flywheel lightning. A h89, nismo springs, 15# flywheels, and the smallest tires you can find a b210 will feel like it has 200hp, but probably only make 90, if you slammed it and welded the diff, it would feal just like a go kart.

[RedBanner]

The most serius a series ive ever delt with was an a14 with over sized a15 pistons, with the tops shaved off flat so they didnt come above the deck., h89, nismo spring, light flywheel, cam and su carbs. It felt like a ka-killer. I did.have questions about how much ring land was left after shaving the pistons, but he couldnt tell me.

[Kirden]

Thanks Banner. I'm planning on getting some valve springs, rocker arm spacers (why not right?), and eventually a cam regrind. I just didn't know if larger than stock valves or extra machine work would be a good idea with the H89.

This engine is in unknown shape. All I know is they PO said it was swapped in, is a JDM import, and never idled correctly (vacuum hoses are very suspect here) so it was parked for 4-5 years before I got it. I figure the safest thing is to rebuild it now considering I am moving out of state in a year and would rather have the B reliable than have to call AAA to get it home.

If anyone has a junk A-series head that they wouldn't mind letting me use to modify and shave the flanges on the manifolds that would be great. I'm kinda scared to jinx it but I think the bogg manifold flanges are off because holding them up to the kirk manifold doesn't even look close to a match.

[RedBanner]

There are so many port desighns, big oval small oval high oval low oval round, that maybe its built to match a different port? Or do you meen there not square?
As for valves, bigger wouldnt be worse lol. I think you can get another mm or 2 without changing the seats, just recut the stock ones. It would possibly give you a few percent more hp in the higher rpm range, but if your paying someone to do it it might not be a good investment, the money might not equal the benifits.

[RedBanner]

Ive never messed with this type of intake, are you able to leave the peice of aluminum inbetween the flanges? I would have to assume it needs to be cutt off to fit, exaust should be there.

[Kirden]

Sadly Kirk and Bogg used different flange styles. The diagram I provided to Bogg for the flange was the 5 peices flange, but the Kirk flange is the 3 peice style. I have to cut the aluminum from the intake (it was only there to line up the spacing for manufacturing) and decide if I want to modify the bottom of the intake flange or the cross section between the exhaust flanges. I am leaning more towards modifying the intake since it has so much more material to work with and the flange is much thicker. I just need a junk head with the same manifold bolt pattern as the H89 head since this is only going to be used for flange fitment.

I guess I could just wait until I pull the head for the rebuild. Atleast then the machine shop can modify the manifold and I won't have a chance of destroying it... If the valve seats are in good shape I'll probably stick with stock. If not I may oversize 1mm and get a fresh valve angle job. I just have to remember that this won't be a race engine, so no need to go overboard.