Cam timing corrected, now seeing less boost... - Boost Forum

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Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 4:32 PM
hey guys, i recently found out my cam timing on the LD9 was off a tooth (thanks dad lol). so threw a new timing chain/gears/guides in and got the timing 100% spot on perfect. now, before the car would see around 9-10psi (via M45) with the timing off a tooth. NOW it is seeing around 6-7psi. i understand that cam timing events certainly can affect boost levels but what i dont understand is why i LOST boost. does this mean the engine is THAT much more efficient? did a 5speed swap at the same time so honestly i cant tell if it lost any power down low or gained any up top. i feel that it pulls harder on the interstate just passing traffic, etc though.

i am running the straight up LO cams, as well. i dont know that anybody else has done these with an m45 so its hard to gauge the boost level as in just comparing to other builds.

could it possibly be bleeding off more boost with the timing corrected now? hell maybe it woulda been better to leave it alone idk...

im not the brightest when it comes to cam timing events and such so an explanation in laymans terms on this would be greatly appreciated.



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!

Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 4:37 PM
Think of it this way since psi is the opposition of flow.

If the valves are now more open your going to have lower opposition to flow, thus lower boost psi. If your valves were not as open then your going to have a higher opposition to flow, thus higher boost pressure.

On the M62 I started out with 12psi with stock exhaust and non intercooled. I then went down to 10psi when I intercooled it, and now im down around 9 psi after the exhaust. But it makes more power with lower psi because there is less restriction.
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 4:47 PM
ok cool. completely understood that...

now, what i dont understand is how the valves are now not open as much? cam timing doesnt affect the actual specs of lift and duration, they do affect at which point they act though. so basically what i am gathering here is i lost cylinder pressure and/or the boost is not staying in the cylinders as long as it was before. does that sound right?



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 5:26 PM
Hmm...how do I word it...

With the valves not as open at a given time your creating a restriction.

It is covering half of your intake ports up. Youd get higher boost.

The engine is a air pump and if the parts arent working in the correct "time" its going to pump less air..? That one may be a bit off.
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 6:56 PM
lol i know what ur getting at. oh well, im putting a different engine in soon, has a ported head and HO cams so yea, might see 2 psi then haha



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 7:00 PM
It has to do with the overlapping of the intake and exhaust cams as well. If it wasn't timed right it's possible that there was little to no overlap. Just remember less psi doesn't mean less cfm. Like Philly was saying it's not uncommon to see intake and exhaust mods reduce psi but increase cfm.



"In Oldskool we trust"
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 7:09 PM
well one positive thing i have definitely noticed, my crusing IAT's have gone down, closer to ambiant, and my WOT iat's off meth definitely arent as bad. on meth, holy hell it really keeps it in check, and in some cases, depending on ambiant temp, it will drop below the cruising temp which is awesome. i can even blip the throttle for a few seconds under boost just to purge the meth a little bit and it will literally drop the iat's 20-30* in a matter of seconds. this was not possible before.

so, obviously the blower isnt working as hard now, so thats a plus for sure.



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 7:13 PM
That's awesome. I CAN'T WAIT to get my meth kit installed. I was thinking I'll be doing exactly the same sort of purge just to shoot the temps down. The other day I was driving around and seeing 150* WITH a good, working IC setup. Heat soak is the ]:->



"In Oldskool we trust"
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 7:27 PM
dear lord man i was cruising yesterday and my iat's never got above 130* and it was 95 and humid as a mofo out! LOL and i have no heat exchanger!

i actually tried a smaller meth nozzle today too, works much better. the larger one wasnt working out unfortunately. that one needs some real good tuning and a LOT of fuel pulled to make it work right. but once thats done i think its gonna fly with it. dropped down to a 375cc nozzle and dumped a bottle of snow's nitromethane booster in. ohhhhh did she love that. that stuff smells epic. whats really messed up is i can probably dump another bottle in and still be safe AFR wise. it was doing low 11's with just one bottle.

i also ordered up all the pieces to complete my second, water-only setup i am going to be installing into the front s/c soft plug. this one will be my purge so im not wasting the expensive boost juice/nitromethane mix. if a 49/51 water/meth mix can drop the iat's 20-30* just doing a small purge i cant even imagine what straight water spraying directly into the path of the heated air is gonna do.

im gonna be using a stock headlight washer pump i found off a mercedes in the junkyard, and a small, 70cc nozzle for this system. the washer pump should be good for 40-60psi at 12 volts. i was told by the company i got my second nozzle from that it would work just fine on even 30psi so it should be fine for just some purging i would think. if not, ill piggy back two of them together. they are so small you could daisy chain 45 of them together and still have room LOL

the purging definitely does get harder the closer you get to ambiant though. it gets to a point where it doesnt cool any better.





M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 7:38 PM
lol Brad you're insane, I love it. I definitely think smaller nozzles are the way to go for a DD or any car that sees regular street use. Hell I'm gonna run a 175cc just so I don't feel like I'm driving with a live grenade under the hood. Pumps fail, lines split/clog, couplers leak, etc. I'm just looking for a little help with cooling and hopefully some more fuel on the top end so I can lower my damn fuel pressure from 72psi base LOL. Still, I want an ice box like nobody's business. All I want is to watch my IATs go below ambient. I have wet dreams about that happening.



"In Oldskool we trust"
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 7:41 PM
Y3llowCav wrote:

All I want is to watch my IATs go below ambient. I have wet dreams about that happening.


you and me both, bud!



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!

Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 7:48 PM
When I saw those terrible IATs it was a nasty hot day and I got stuck at a lot of lights. I'm wondering if something like these wouldn't help me out. Maybe throw 2 on the back on the intercooler or something. Frozenboost.com has all kinds of good stuff if you haven't checked them out before. But knowing you, it's probably already bookmarked on your browser



"In Oldskool we trust"
Re: Cam timing corrected, now seeing less boost...
Wednesday, July 10, 2013 8:09 PM
lol there is absolutely nothing on that website that will benefit me. yet.



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!
Re: Cam timing corrected, now seeing less boost...
Thursday, July 11, 2013 3:54 AM
Go big or go home. I have been running a big nozzle for years now. Perfectly safe to run on a street car.



FU Tuning



Re: Cam timing corrected, now seeing less boost...
Thursday, July 11, 2013 4:38 AM
Addicted to meth wrote:

Go big or go home. I have been running a big nozzle for years now. Perfectly safe to run on a street car.


i absolutely agree. i will be throwing the big un' back in for tuning thats for damn sure...



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!
Re: Cam timing corrected, now seeing less boost...
Thursday, July 11, 2013 5:23 AM
I think you corrected the problem, and the engine is running a lot more efficient. Now go redyno it.





Re: Cam timing corrected, now seeing less boost...
Thursday, July 11, 2013 6:03 AM
PSI is just for the ricers anyway. More power on less boost is always something to be proud of.




Re: Cam timing corrected, now seeing less boost...
Thursday, July 11, 2013 7:27 AM
well jeez i just find it odd that my setup, with both pullies maxed out is seeing less boost than most see without an os crank pulley and with say a 2.7" snout pulley. i am running the os crank and a friggen 2.4" snout pulley for crist sakes LOL i guess the LO cams make the engine that much more efficient. its not really that surprising when you think about it though as they really are basically the same thing as HO cams but a little bit smaller. and we all know how well ho cams do with turbo's...

these are LO cams, not "secret" cams. they are a matched set, i think this makes a huge difference. and mike, i agree... i cant wait to get it on the dyno. i cant even believe it made 154whp NA with the cam timing off a tooth.. but, that definitely explains how it also put down 175wtq at the same time.... jeez, this motor could have probably made upwards of around 165whp n/a... thats pretty damn insane considering its ONLY internal mods are the LO cams. but alas, she's got a tick now anyway. time to yank it out in favor for one thats got HO cams and a ported head thats ready and waiting.



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!
Re: Cam timing corrected, now seeing less boost...
Thursday, July 11, 2013 2:00 PM
also on a ported blower.Less can be more.


You might just have the new record holder M45 LD9.


Edited 1 time(s). Last edited Thursday, July 11, 2013 2:01 PM


FU Tuning



Re: Cam timing corrected, now seeing less boost...
Thursday, July 11, 2013 10:16 PM
Addicted to meth wrote:

also on a ported blower.Less can be more.


You might just have the new record holder M45 LD9.


after a tune, MAYBE. and i say maybe with the a new motor in the car and the meth system working flawlessly in time with the tune. it does haul ass though but its gotta be pulling mondo timing due to this ticking and it doesnt help that the shifter in it feels like a big flopping effing dildough. i really need to figure out how to get this damn mantapart shifter to work..



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!
Re: Cam timing corrected, now seeing less boost...
Friday, July 12, 2013 4:45 AM
My stock shifter feels like a big dildo as well it sucks ass but its wore out where the ball sits in the shifter assymbuly I put it in gear and damn near feels in nutral lol

I Love My J ♡

Re: Cam timing corrected, now seeing less boost...
Wednesday, July 17, 2013 5:55 AM
-Z Yaaaa- wrote:

i guess the LO cams make the engine that much more efficient. its not really that surprising when you think about it though as they really are basically the same thing as HO cams but a little bit smaller.


That is the silliest thing that I have heard you say brad. .035 lift and 12 duration at 50 are quite a bit in the world of cams, especially the smaller the engine, not to forget that the valve event timing are probably totally different. LO cams were for regular people everyday vehicles the HO cams were performance driven design.

I will agree that the drop in your PSI does suggest more efficiency and rightfully so as they are more agressive cams than factory LD9 cams and the change in your timing allowing more valve overlap, or valves opening at same time. This is engineered to cause a scavaging effect for upper rpms. So basically you are loosing boost through the exhaust but gainimg power because more cfms are moving through the engine. I am interested to see track times. Just an interesting side note, this is the reason you dont want too much overlap in a turbo application. There is so much pressure in the exhaust manifold that reversion can occur and actually blow exhaust into the intake manifold.

The only other thing I can think of that could be reason for the lower psi than others is that you have the od crank pulley and smallest snout pulley and it is possible that you are overspinning the bejesus out of it and pushing it way past its area of efficiency. I hope that is not the case though.



Re: Cam timing corrected, now seeing less boost...
Wednesday, July 17, 2013 7:28 AM
Im surprised no one has asked which cam was off and whether it was retarded or advanced with respect to the crank. Without knowing either of those youre just make a broad assumptions.

If both cams were a tooth off in the same direction then overlap does NOT change.



Re: Cam timing corrected, now seeing less boost...
Wednesday, July 17, 2013 8:04 AM
Brad told me, though I'm having a brain fart as to what it was now.



Re: Cam timing corrected, now seeing less boost...
Wednesday, July 17, 2013 10:04 AM
Brian wrote:

Im surprised no one has asked which cam was off and whether it was retarded or advanced with respect to the crank. Without knowing either of those youre just make a broad assumptions.

If both cams were a tooth off in the same direction then overlap does NOT change.


thats exactly what i was saying. the CRANK dots were off a tooth, making BOTH cams off.



M45/OS crank/2.4 snout. Now with 5 speed! It's nice to be injected but I love being blown!
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