Thread: What kind of boost psi are you seeing on 2.8 setup?

Hey guys I'm just trying to see if the numbers I'm getting are accurate, I've thought I might have a boost leak after installing my intercooler. I know its normal to lose a little pressure but I was at about 10-10.5 on a 3.2 and after the intercooler I'm running a 2.8 but am seeing almost exactly the same boost pressure 10-10.5#. I have a topswapped, headers, fsic, ported tb, ported gen3 supercharger, ported lim, 1.9 ytrr. Thanks for your input everyone.

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I got 11psi. Headers cam ssic 80mm t.b

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I hit 11.5 max boost on a 2.6 pulley. I like to think it's called diminishing returns. the faster you spin the blower the hotter it get's and the less boost that is made.

Originally Posted by Scottydoggs

i see 12 at the top of second gear, 1 st gear i only make 10.

we got pretty much the same set up. but i have ported heads.

3.2 made 8 ish, 3.0 made 10 ish, the 2.8 now 12 ish.

Ya we have identical setups pretty much. I wonder if it's just the summer heat causing my boost to be lower then I would expect after dropping .4 pullies. On a side note I can't even measure top of second or third. Its weird I have zero kr all the way through first and all the way through 2nd or 3rd right up till about 5k and ill get 1-2* out of no where.

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Hmm. Idk maybe I'm just over thinking it. How much boost do you guys lose going from winter to summer. Another factor in my situation is the last time I had logged boost it was 40* out back when I was non intercooled but now I'm intercooled and it's about 90* on average now

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I thought even 1* was bad when you were running a small pulley? Like 1* on a 2.8 would be like 4* on a stock pulley. I have no idea if that's true but its what I heard.

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Originally Posted by Scottydoggs

if you own a tuner, its best to not have anything more then blips of kr. any kr thats not going away you need to address.

Well it doesnt happen at night time when its 80-90* out only in the day when its 110+ so I'm just being cautious to stay out of full boost in that area and it'll cool down quite a bit in October so I think ill be okay when that happens.

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Originally Posted by Scottydoggs

before i added meth when i was still on a 3.2, once temps went to 60 or less i could run 3 degrees more wot timing.

really hope i can do the same still.

just adding meth let me drop to a 2.8 and add 3 degrees more wot timing. in the dead heat of summer here. im running washer fluid and i use a gallon every 1.5 weeks or so. that 2 bucks i can afford to spend lol

Ya I'm running 19.5* timing right now on my 2.8 so I dont plan on raising it any higher when winter comes in pretty content with where I'm at. The only things I've been thinking about is getting a built transmission and possibly a gen v swap but after a turn down adapter, the gen v, the throttle body adapter, and all the work modifying my gen 3 ic or buying a gen v I'm not sure it's even worth it. Especially when my gen 3 is already ported with a fresh rebuilt snout.

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Hey scottydogs!!!! I was just thinking that I never replaced my spark plugs when I installed my intercooler so I'm wondering if I should step down to 103s instead of my current 104s. What are you running?

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Originally Posted by Scottydoggs

funny, but i just tried 103's, car hated them. got 104's again gaped at 0.48 and shes all happy.

What do you mean she hated um? Like just felt like lost power? I know 103s are usually recommended when running a 2.8 setup especially with are higher compression. But since were both intercooled and running e85/meth cooling I wondered if it was still a good idea.

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Originally Posted by Scottydoggs

they misfired all over the place no matter what gap i tried. put the old 104's back in and she came back to life, installed new 104's the next day, runs just fine still.

i only went with the 103 to see if they would help/work good i suppose, my 104s were two years old, not that they had any where near 10,000 miles. i felt it was time to change em.

Well I just got done installing the autolite 103's and my car seems to love them. I haven't done a full blown comparison yet but I can tell it deffinately helped with the little kr I was seeing in the top of 2nd and 3rd. I will let ya know more accurately how much it helped tomorow when I can take it out longer. I also gapped them at .46 which is a little less then what's reccomend which I believe is .50 but I was running my 104s at .50 and that worked great so since this is a colder plug I figured I would shorten the gap just a tad.

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Ya I change my plugs every 2k and my oil every 1.5k or basically whenever I have a day off and I'm extremely bored. Haha, ill probably buy some 103s since there so cheap and try them out see if it takes care of the little kr I'm getting. If not ill take drop back to 18* timing. I should probably plug my caspers hotwire back in although I don't think that's the problem since I have an aem pump and my afr seems to stay around 11.5 when the kr hits.

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