A
Anonymous
I finally did the first dyno pulls on my new boondockers turbo (gt28) with low comp headshim (9-1).
We ran a mix of 50% c16 and premium.
First pul was at 12psi (and we hpoed to get up by next pulls)
The dyno numbers were extremely low... like 150hp, the header was glowing red-orange and kept getting the CODE 14 on the display. We finally came to the conclusion it was because we have almost NO vacuum at idle. (like 4-5 in-hg instead of normal 10-12in-hg)
We aborted dyno session at that since whatever we tried always ended with code 14 and no vaccum and extreme poor idle.
later we took engine compression and we are at 110 on all cylinders (all being equal) on a very good snap on comp tester...
Then we decided to give the thing a try on the snow just in case.... WOW this must be the most impressive 150hp I ever seen (BUT NO CODE 14 then) but still extrememe poor idleé hard to re-start and no vacuum...
We tried everything on the boondockers controller to improve idle and low range but its not near a good quality idle.
Can it be burn valves, mistimed cams, misadjusted throttle blades (not closed enough), misadjusted idle circuit or simply my engine passing away?
We ran a mix of 50% c16 and premium.
First pul was at 12psi (and we hpoed to get up by next pulls)
The dyno numbers were extremely low... like 150hp, the header was glowing red-orange and kept getting the CODE 14 on the display. We finally came to the conclusion it was because we have almost NO vacuum at idle. (like 4-5 in-hg instead of normal 10-12in-hg)
We aborted dyno session at that since whatever we tried always ended with code 14 and no vaccum and extreme poor idle.
later we took engine compression and we are at 110 on all cylinders (all being equal) on a very good snap on comp tester...
Then we decided to give the thing a try on the snow just in case.... WOW this must be the most impressive 150hp I ever seen (BUT NO CODE 14 then) but still extrememe poor idleé hard to re-start and no vacuum...
We tried everything on the boondockers controller to improve idle and low range but its not near a good quality idle.
Can it be burn valves, mistimed cams, misadjusted throttle blades (not closed enough), misadjusted idle circuit or simply my engine passing away?
Oak Hill
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If I where a betting man, Cam Timing!
jornab
Newbie
I agree with Oak Hill. It sounds like the cam timing is wrong. Have experienced the same problem on an Apex turbo.
rxrider
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Are you positively sure you are adding extra fuel under boost? How is your C0 set, on a MCXpress Apex kit we had to set it at -5 to get the idle/low end rpms working, stock setting is 0. I've seen another Apex that didn't get enough fuel under boost, and with clutches set up for turbo on the first test ride it would not rev past 9000. Why? not enough fuel, thus making only stock HP so it couldn't pull the Supertips. It went deto cause of the lack of fuel. I hope this is not the case with your sled.
Need for Speed 2
TY 4 Stroke Junkie
no vac is the key to problem here. not fuel. not idle prperly with no vac tells you cam timing is off. recheck cams you will find problem.
A
Anonymous
Yes no vac is the key!
One thing I forgot to mention is I ground the intake cam gear to retard it (60 thou) and did not touch the exhaust cam gear. Shim advanced the exhaust by itself.
So my exhaust cam is a bit in advance and intake a bit retarded in comparison to stock.
I will recheck just in case I would have made an error in there of course!
One thing I forgot to mention is I ground the intake cam gear to retard it (60 thou) and did not touch the exhaust cam gear. Shim advanced the exhaust by itself.
So my exhaust cam is a bit in advance and intake a bit retarded in comparison to stock.
I will recheck just in case I would have made an error in there of course!
slymax
TY 4 Stroke Junkie
It'll be the cam timing off. Very easy to get it wrong, After you get it back together, you should rotate the engine by hand for complete revolutions and recheck the timing marks. The exhaust cam will be slightly advanced and the intake cam hole should line up with the mark on the cap. You should also use a feeler gauge to make sure each valve has clearance, that way you know for sure that the shims are in place. Let us know what you find.
If 10"-12" vac is normal on an Apex...(stock cam/compress)...I got a problem too.
on the track stand with my chepo $20 NAPA vac/press guage I get:
4" at 1500rom
5" at 3000rpm
6" at 5000rpm
after 5000rpm the gauge switches over to pressure
on the track stand with my chepo $20 NAPA vac/press guage I get:
4" at 1500rom
5" at 3000rpm
6" at 5000rpm
after 5000rpm the gauge switches over to pressure
KnappAttack
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Its sounds like cam timing for sure! Hammer, if that is on your blower sled it wouldnt have vac. like a NA or turbo sled.
Mike -- Yep, it's on the SC sled, measured at the MAP sensor fitting.
GotMoreBoost
Veteran
mulot30th said:
I am just wondering if you got it figured out yet?
A
Anonymous
I haven't even looked at it today.... had no time for that sorry....
I will first have to undo a lot of things to remove valve cover.... should take at least tow or three days of work to get there...
I will first have to undo a lot of things to remove valve cover.... should take at least tow or three days of work to get there...
GotMoreBoost
Veteran
mulot30th said:
I too have A boondocker GT28 turbo kit. We have not got it going on the snow yet but it seems to idle fine in the garage. I am also curios on what Boondockes told you about what upgrades and clutching you should purchase?(big injectors, pistons, blow off valve,...)?
A
Anonymous
I have big injectors, fuel pump, head shim and hallman boost controller.
Last thing I did now was to start it cold (choke mode) and it gets 5 in-hg vac .... when its to normal temperature, the vac goes down to around 1 in-hg.... And it would eventually stall. Then I can't get it to start again until it gets cold enough to go in 'choke' mode again.... and so on...
I am starting to think head gasket problem....
Last thing I did now was to start it cold (choke mode) and it gets 5 in-hg vac .... when its to normal temperature, the vac goes down to around 1 in-hg.... And it would eventually stall. Then I can't get it to start again until it gets cold enough to go in 'choke' mode again.... and so on...
I am starting to think head gasket problem....
Travis Moore
Expert
That compression # is VERY low.
T
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