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vvt is cool. but it adds more complications. and i remember a thread on MT claiming that vvt heads dont like to go over 7.5k. (something about the harmonics in the head) which is a bummer but you cant have your cake and eat it too i suppose.
 

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vvt is cool. but it adds more complications. and i remember a thread on MT claiming that vvt heads dont like to go over 7.5k. (something about the harmonics in the head) which is a bummer but you cant have your cake and eat it too i suppose.
Ive heard of the harmonics issue as well. I'm not sure if it has to do with the vvt actuator or something else. Not that you really need to rev to 8k if you have VVT working for you. A well tuned miata with vvt and a 7200rpm rev limit will make a much better torque curve than a BP4W reving to 8.

FWIW: faeflora revs his built vvt head to 8k with stupid boost. Of course, 8k VVT heads and sawzalls aren't for everyone. :woolery:
 

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brontosaurus
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Well good luck. It sure sounds like all your bases are covered.

The stock injector ports on the bp4w would make some awesome methanol injection ports since you are using the ones on the TWM throttles. Could be a similar setup to what the new toyota86 is running, with two banks of injection for detonation resistance.
 

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Discussion Starter #404
I dont really understand methanol injection or its benefits. Nor have i done any research on it. Obviously it would require an extra fuel tank of some sort and im sure the megasquirt would have to be sufficiently modified to run a second set of injectors at a diferent rate.
Is this something that runs all the time? Tell me more?
 

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brontosaurus
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Well in your situation it would only be of benefit if your compression was holding you back from adding more timing. Methanol greatly cools the intake charge, and is a higher octane fuel. Because of these two benefits you can tune much more aggressively due to the fuel acting like it is a higher octane fuel. Average rule of thumb is you spray about 12-15% of your total fuel system. This can controlled via rpm window switch, Your EMS, or through a seperate controller like devils own or snow performance sells. It's really up to you and your specific needs.

I don't necessarily think this is a route for you to go just yet. Just something you can look up and see if it has anything to offer you specifically. If you can't add anymore timing to your map because you were restricted by your current fuel source, then there is no need. It will cool your intake charge, but on a non FI car if this was the only benefit I would not personally bother. It's a whole other system to add and maintain, so without the need it's just another headache.
 

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Discussion Starter #407
Thanks for the info. Im going to stay away from that. When I have the head apart we are going to fill and blend the factory injector holes to improve flow. as of now there are NPT plugs in them which has to disturb flow somewhat.
 

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brontosaurus
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Sure can. You're just going to need to do it a bit differently. Really high compression being the first difference. Then the rest is in the tune. You can run much higher cylinder pressures, so you won't need as much overlap. It's all just a balancing act, any engine tuned properly with any type of aspiration can take benefit of high octane.

Edit: Hey look what Emilio just posted up. Should be a great indicator of what is to come with your new cams. Those 9mm were holding you back for sure.

http://www.miataturbo.net/showthread.php?t=63455
 

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meth/water is cool, but you gotta have good equipment.. and that adds more $$$. and, e85 does wonders.

that being said. you can tune for e85 on n/a...? never seen and n/a application, only FI...
Yes easily, my mate filled his NA6 up with E85, went into pay and the clerk goes "you know your car can't run that fuel"

smartass him goes "you'll see"

pushes the car over the parking spaces, sits there for half a hour richening his A/F by about 30%. Cranks over and starts, ran like **** because it was a rough tune but the fuel station clerk was amazed.
 

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Discussion Starter #414 (Edited)
oK. Sounds like the cams he is using is the integral stage 5 that is now ground by megacycle.
Thats encouraging that he made that much power with lower octane and lower compression than me.
so since i have higher compression and slightly better gas here in FL and my cams will have .080" lift more than his i feel pretty good about it. Plus i have the itbs so as not to restrict intake flow...

And a much better header!
 

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brontosaurus
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Well with sequential injection/ignition and individual monitoring, either 4 EGTs or 4 widebands, you could individually tune each cylinder. I have no idea how much power this could account for. I guess worst case scenario you could have the best possible tune imaginable.

You should try different length velocity stacks as well. I just posted an interesting test done on a Neon in the thread about the variable length itb runners used in the 787b. The individual tested different length runners from no runner through 11" long. There was as much as 25whp and 20ft/lbs to be gained at 4,500rpms with only a 10hp change at the top end. This would be tuning for the proper Helmholtz frequency. Should prove useful chasing the last few ponies.

http://clubroadster.net/vb_forum/showthread.php?t=56836
 
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