Re: SP# or Dual Plane for Eventual Boosted 350 Thank you Mark! I was actually planning on using a self learning fuel injection throttle body setup, but it sounds like the single plane may not even be needed until I run more than 6psi?
Re: SP# or Dual Plane for Eventual Boosted 350 My son is running the SP3 intake on his internally stock 350. His has the Holley intake...because he is running a 750DP on it. Just had a set of Doug's ceramic coated headers installed, along with an "American Thunder" 2 1/2" dual exhaust installed. First start of the day, it's a bit cold hearted, but after a few minutes of warming up, there is no stumble. He can bark the "tire" off the line, and that's with 3.08 gears, and 295/50/15's (Off idle, no brake load) Honestly, he is in love with it right now.
Re: SP# or Dual Plane for Eventual Boosted 350 I lost VERY VERY little, actually cant feel any difference in my low end, between the Stage 1 and SP3.
Re: SP# or Dual Plane for Eventual Boosted 350 Under boost I don't see a lot of difference for either manifold , just a trade off between lower end and upper end same as without boost. The sp would give you more options later on. But as far as boost on a 9.4 SP engine you will need to be careful of detonation. I'm thinking either e85 conversion or alky injection with highest octane you can run. Good luck . Get good brake upgrades
Re: SP# or Dual Plane for Eventual Boosted 350 No more boost than you plan on running 9.4 would be fine if timing is kept in check, I would run a Razor or AIS meth kit and no intercooler on such low boost
Re: SP# or Dual Plane for Eventual Boosted 350 Real world feedback will always trump mathematical or scientific theories.
Re: SP# or Dual Plane for Eventual Boosted 350 I was thinking about maybe switching to TA composite head gaskets that are thicker which should drop my compression a bit and hopefully give me more headroom as far as detonation goes. Any other easy ways to loose some compression (besides finding a non SP 350)? No intercooler needed on 6psi? Interesting, that would help save me some $$! At this point I'm leaning towards the SP3. Everything hinges on the results of the compression and leak down tests though, if those don't check out I have bigger problems. Just ordered a leak down tester from Summit! I live pretty close to their Arizona warehouse so stuff usually arrives in a day or two. Is there anything special I should do to try and wash out the coolant that fell in my oil when I took off the intake out? I was going to buy some extra oil and pour it over the lifter valley with the drain plug open . . .
Re: SP# or Dual Plane for Eventual Boosted 350 This often doesn't work. The compression # is less important than many other variables. Not theory, fact. If you already don't have much quench action, then it can help. There is a "danger zone" pertaining to quench distance. There still is quench on an open chamber head, it just isn't a flat, machined surface. Coolant temp and exhaust valve temperature via seat contact (width) have significantly more influence than a .4 or whatever compression bump.
Re: SP# or Dual Plane for Eventual Boosted 350 Agree.., chamber, vehicle weight, gearing, cam events, environment etc all contribute to detonation more so than the actual compression number. And yes boost is heat and with 6psi or anything under 10psi for that matter inter cooling isn't really needed, and to exemplify what has changed and what is done now a days, its nothing unusual to see a 11.1 and even higher sometimes hot air setup with 12or so pounds running 20+ degrees of timing on e85 or a 93 and a heavy squirt of meth...and live. Tune has to be spot on cam selection is pivotal, but years ago the above would have been ridiculous to even consider.
Re: SP# or Dual Plane for Eventual Boosted 350 Now granted the LS Body stuff is aluminum block,aluminium head and a very highly engineered efficient engine but bolting a hot air blower on its 10.1+ bottom ends are done daily with full warranties, granted an iron 1970ish 350 isn't in the same universe as an LS3 but just goes to show that old theories on boost are being tested and terminated
Re: SP# or Dual Plane for Eventual Boosted 350 Other than the material of the head casting, the major attribute to the LS's gift of octane tolerance IS the shape of the combustion chamber and it's manner of behavior imparted to the squeezed mix prior to the combustion event...much like the general shape of Buick chambers. Nothing really magical about the LS. The electronic benefits would hold their value on any engine platform. I'm agreeing with you Hugger but offering a distinction; I'm suggesting to the OP to NOT move the quench distance further out until they fully understand what's happening and are in command of the variables. The high compression combinations you say would have been ridiculous to consider years ago were being done successfully by folks with the education and understanding to do it, just not by the general enthusiast that formerly got their information from magazines. The reason we see more of it now is because of the dissemination of information reaching the masses. The info has always been there. If removing the heads isn't an obstacle, I can think of many better improvements to the engine. Some relatively inexpensive ones, too. I guess all of this hinges on the OP's ability to tune things...or follow an EXACT recipe rather than picking up out of context tidbits from the internet.
Re: SP# or Dual Plane for Eventual Boosted 350 This is great info! I realize that I'm stepping into a vast world that I know little about when it comes to forced induction and how the heads/cam etc work with it. I know the basics of how turbo works but the 2 years will also give me time to do more research before I do anything drastic to the engine. My idea of the head gaskets comes from Mark, but he also said it may be easier to just find a lower compression engine to build. He says that he doesn't really do anything besides a new cam, lifters, and valve springs for a 6psi 350. As far as tuning I am a newb there also. I will be testing my power timing skills when I put my new HEI in (when the tests check out, when the manifold goes on ect. ect.) but I have never tuned a carb or anything else really. The fuel injection throttle body units they are coming out with now make me hopeful that I can dial things in with a laptop, and the unit I was looking at can even control timing through the coil. I am still very far off but it definitely helps me to brainstorm and make a solid plan of action!
Re: SP# or Dual Plane for Eventual Boosted 350 Just for some info to help you out... If you don't need to remove the stock intake manifold then leave it on for now... And leave the engine together. I had a car I was building that I sold recently and the new owner recently had it on the chassis dyno and it made 460 hp and 460 tq at the tires at 10 psi using the burton machine kit. The engine build was super super mild. It was basically a stock rebuild except adding some trw forged pistons, Ta stage 1 valvesprings, single plane intake and a mild poston 114 cam. No real head porting, stock valves etc and it runs 11s in the quarter with street tires and a heavy weight of about 3900 pounds with a roll bar etc. My current car was built by Mark and it ran low 10s, weighs under 3000 pounds and also has a mild engine with pretty much the same combo as above... Mine made 450 hp at the wheels on low boost with about 22% converter slip. Swapping in a better converter And a new engine with the alum heads soon. Regarding the compression, the engine in my old car has 10:1 pistons but measured out to 9:1 compression and runs great on boost... I would not worry too much about the compression but I would buy another 350 to build up with nice rods and pistons while you get he turbos up and running.
Re: SP# or Dual Plane for Eventual Boosted 350 Thanks Sean, this is useful info. 460hp/460tq is amazing with that low boost and mostly stock engine! If I can get somewhere around 350hp from 6psi I'll be happy. Unfortunately the intake is off already, I had to take it off because it was leaking oil from the front seal.
Re: SP# or Dual Plane for Eventual Boosted 350 No need.. A cheap methanol kit would be added mind comfort. I would get the 8lb springs. If you don't you'll get them eventually:TU:
Thanks!! I just realized that I need a warm engine to get accurate results with either a compression test or leak down test . . . so I will just have to buy the intake, install it, and hope for the best. I will do both tests once the engine is running again.
Re: SP# or Dual Plane for Eventual Boosted 350 I was going to add more, but you're doing a fine job already. The text in bold reiterates something I've said a long time ago. Nice to see it being brought up again. :TU: Gary
