Going to the dyno tomorrow....update with bad pics 11/26 :(

Josh · Post by **Josh** » October 4th, 2006, 11:45 pm

CJ,

WHAT ARE THE NUMBERS !!!!!!!!!!!

Its Killin me dont make me call you this late at night

cjthor · Post by **cjthor** » October 5th, 2006, 1:02 am

Well it seems theres a problem. Corksport thinks the cam timing is off. The engine flatlines at 250. Gonna pull the valve cover and take a look..

Josh · Post by **Josh** » October 5th, 2006, 8:26 pm

what plugs are you running?

Thats what Bugs's problem was. was putting down 148 WHP, changed the plugs to a colder plug off of a MX6, and BAM next pull was 212 WHP.

just a thought.

hey did they actually cut you new cams or did they put the Miata cams in. i rember them calling me about the Miata cam swap for your car. just wondering if they actually went through with it.

cjthor · Post by **cjthor** » October 5th, 2006, 8:54 pm

Josh wrote:what plugs are you running?

Thats what Bugs's problem was. was putting down 148 WHP, changed the plugs to a colder plug off of a MX6, and BAM next pull was 212 WHP.

just a thought.

hey did they actually cut you new cams or did they put the Miata cams in. i rember them calling me about the Miata cam swap for your car. just wondering if they actually went through with it.

Miata cams yes.

BuGS · Post by **BuGS** » October 5th, 2006, 9:12 pm

cjthor wrote:Well it seems theres a problem. Corksport thinks the cam timing is off. The engine flatlines at 265. Gonna pull the valve cover and take a look..

Got any sheets or anything? A/F Ratio? What boost??

Josh · Post by **Josh** » October 5th, 2006, 11:41 pm

they should have a cam deg wheel. and dont you have adjustable cam gears. they dont really have any excuse if the timming is off. whats the lift and duration of the cams? that could be the problem. cause if they are stage two N/A cams then its possable that it could plateau. really depends on what the lift and duration are. and if your intake and exhaust are matching or not. if they arnt than thats the problem for sure.

cjthor · Post by **cjthor** » October 6th, 2006, 12:00 pm

No paperwork as of yet. Waiting for a call this morning from Jason. Derrick said the car was running way fat. The car has plenty of gas. Even when leaning out the car still plateaus. They think either cam timing is off or the intercooler piping is too small. I dont recall the cam numbers. I will try and get that too today.

BuGS · Post by **BuGS** » October 6th, 2006, 7:14 pm

oh ya your IC piping is like 2". You might need to go 2.5 or even 3"... But I don't know for sure...

cjthor · Post by **cjthor** » October 6th, 2006, 7:17 pm

BuGS wrote:oh ya your IC piping is like 2". You might need to go 2.5 or even 3"... But I don't know for sure...

but would this cause the hp to just flatline?

Josh · Post by **Josh** » October 6th, 2006, 8:10 pm

cjthor wrote:
BuGS wrote:oh ya your IC piping is like 2". You might need to go 2.5 or even 3"... But I don't know for sure...
but would this cause the hp to just flatline?

yes it sure can. if your piping is too small you can only force so much air threw it at once. i am running 2 1/4",

you should try stepping up the piping for sure. 3" might be a bit on large side. your not running a T4, but 2 1/4" or 2.5" would proabably do the trick.

cjthor · Post by **cjthor** » October 6th, 2006, 8:40 pm

Josh wrote:
cjthor wrote:
BuGS wrote:oh ya your IC piping is like 2". You might need to go 2.5 or even 3"... But I don't know for sure...
but would this cause the hp to just flatline?
yes it sure can. if your piping is too small you can only force so much air threw it at once. i am running 2 1/4",

you should try stepping up the piping for sure. 3" might be a bit on large side. your not running a T4, but 2 1/4" or 2.5" would proabably do the trick.

pretty sure i am running 2-1/4 on the pipe. Jason seems to think I have valve overlap. He is going to run a compression check and a visual check of the valves on Monday. Is all of your IC piping the same diameter? I seem to recall derrick saying that the piping before the IC should be smaller than the piping on the other side?

JWMotorsports · Post by **JWMotorsports** » October 6th, 2006, 10:57 pm

2.25 is a bit small for the turbo your running but should be large enough to flow for 300WHP. 2.50 IC pipes should be good on your car and you could even step the cold IC pipe up to 2.75 or even 3.00 like mine. The advantage of using a larger cold IC pipe is that it creates and even denser area for the pressurized air to flow to. This allows the IC to breath better and flow more. It also increases your plenum size at WOT. This is how I'm making the power I am with an under sized IC (I ran out of money to upgrade it to the 24x12x4 IC so I'm stuck with the APEXi Silvia IC).

What does your timing maps look like on your standalone? The GT"R" series turbos seem to really like 10* of advance at full power. I'm running 28* Advance under vac. and slowly step it down to 10* advance at 16+psi. I'm currently running 23psi on the street with 93 pump gas. This timing map is still some what conservative. As for AFR's I cruise at around 15-16:1 AFR and EGT's around 900*F on the interstate. WOT you can target 12.0:1 at peak torque and then gradually lean it out to 12.5:1 at peak power. This gives you a hair of a safety margin incase you get a tank of bad gas. It also gives you a little bit cooler EGT's at WOT. You can push the envolope and lean it out further by running 12.5 at peak torque and gradually lean to 13.1 at peak power but it's risky and usually only done on race cars with plenty of money behind them

If your running richer than the above AFRs I recommended the only thing it is worth is for cooler EGTs or if your IC is way undersized and your seeing high air temps at the intake ports. EGTs are something that gives you a solid indication how the motor is running with the AFRs your using. Don't go by just AFRs.

Cam timing is crutial in forced induction and to much over lap allows for cyl. pressure drop. Forced induction engines like mild cam durations with monster valve lifts. Since your running stage 2 miata cams you may need to use adjustable cam gears to decrease the valve overlap. I believe your supposed to retard the exhaust cam timing. This should also help with the turbo spooling making it spool faster. If you left the exhaust valves close for a few degrees on the exhaust stroke the cyl pressure would start to rise again but then as the exhaust valves open it would create a higher velocity exhaust pulse. Kind of like increasing fuel pressure to get a fuel injector to flow more. In this case you cyl pressure is your fuel pressure and the exhaust valve ports are your fuel injectors.

cjthor · Post by **cjthor** » October 7th, 2006, 11:51 am

Well Corksport is doing the work as they built the motor. Im gonna shoot a link to this thread to Derrick and see if he has any input.

Josh · Post by **Josh** » October 8th, 2006, 3:33 pm

JWMotorsports wrote: Cam timing is crutial in forced induction and to much over lap allows for cyl. pressure drop. Forced induction engines like mild cam durations with monster valve lifts. Since your running stage 2 miata cams you may need to use adjustable cam gears to decrease the valve overlap. I believe your supposed to retard the exhaust cam timing. This should also help with the turbo spooling making it spool faster. If you left the exhaust valves close for a few degrees on the exhaust stroke the cyl pressure would start to rise again but then as the exhaust valves open it would create a higher velocity exhaust pulse. Kind of like increasing fuel pressure to get a fuel injector to flow more. In this case you cyl pressure is your fuel pressure and the exhaust valve ports are your fuel injectors.

thats exactly whats wrong with my car rite now. i forgot to set the exhaust retarded a bit. with as big of cams that i have i need to.

the only reason i ask what the lift and duration the cams are, is its a common mistake to purchase differnt lift and durations for exhaust and intake side. and when you swap them into the DE head, your changing the flow dramatically, so you will be taking in more air than the engine can let out. so its kinda crutial that they are both the same lift and duration. there is one other option in doing the swap for guys that want to do it cheep. and thats to buy two intake cams, and cut the crank angle notch off of one side. that still will give you a few extra ponies. and would be easier to time.

cjthor · Post by **cjthor** » October 9th, 2006, 8:26 pm

Ok called today and found out the the intake cam was retarted and the exhaust cam was advanced. Both by like 2 teeth on the belt. After this was fixed the car is MUCH more lively. Going BACK to the dyno wednesday or Thursday.