Too much boost

Topic: Too much boost (Read 4046 times) previous topic - next topic

Too much boost

February 06, 2005, 05:50:13 PM

I went to the track this weekend and put the 17lb pulley on the blower.
Car got insane until half track, and decided to spit up both head gaskets #3 & #7. Car still went 13.33 at 90mph, (on street tires)after pulling it out of gear at 1/2 track and coasting. Guess there's not enough injector ( only 42lbs).

:shakehead

Re: Too much boost

Reply #1 – February 06, 2005, 06:45:15 PM

wow how many ponies you got about? also you should post your whole time slip, so we can see stupid little things like your 60' time and such.

Re: Too much boost

Reply #2 – February 06, 2005, 09:55:48 PM

Dyno on the motor was 379 at the flywheel, don't know what it is with the blower. ( Engine is 9.0 to 1 )

Sixty foot time was 2.03 (street tires)
:evilgrin: :evilgrin: :evilgrin:

Re: Too much boost

Reply #3 – February 06, 2005, 10:42:09 PM

So what was the 1/8 mi time and mph???

Re: Too much boost

Reply #4 – February 06, 2005, 11:59:39 PM

The 1/8 mile was 7.67 at 86.98mph. I don't have a scanner so i am gonna try to borrow my friends digital camera and upload the pic of my time slip.
:evilgrin: :evilgrin: :evilgrin:

Re: Too much boost

Reply #5 – February 07, 2005, 10:54:53 AM

i have a few questions for you and a few opinions of mine that might help you...

1 the dart heads what cc are they? and how did you come up with a comp ratio of 9.0to1 my heads are 60cc and my comp is about 9.6to1 give or take..

2 what block are you useing? stock,A4,sportsmen, so on...?

3 what brand mass air are you useing?

4 is your block oringed?

5 why 17psi of boost and a 55 shot NOS?

now just hear me out on this one i'm not trying to start a flame war just trying to help

my first opinion..

on the 9.0to1 if that is what it is if you have 63cc heads with the 17psi of boost with the 55 shot of NOS is ticking time bomb..

why?
1 injectors are to small for that level of of boost and comp..

2 topping it off with the NOS..

3 again i don't know which block your useing but i will soon find out..

on my second opinion..

is on the mass air if your useing a C&L 76mm it's not good enough for your set up it uses a sampling tube to fool the electronics.. and will peak out to early with a blower setup use a 90mm lighting meter which is calabrated allready for 42's or use a 80mm pro m..
the reason why i said your useing a C&L is becauce thats the brand that i know that uses a 76mm a pro m bullit is 75mm..

next..

is about the block .. a stock block will only handle 600 flywheel HP.. before it splits in half..

i'm not saying you won't get a number of passes with that much HP but it will split in a short time at the track with a enough runs on it..

now about the block being oringed..

even if you did have about 7.8to1 comp the block should be oringed running that much boost.. i'm only running 6psi of boost and my block is oringed..

i oringed my block just to play it safe.. and i have'nt blown a head gasket in two years..

in my opinion running 9psi or more is standard to oring the block..

now one thing i would say is in your spec's it says your running a 3core intercooler.. your smart in doing so if you plan to run that high of boost.. but again in my opinions depending on your true setup 17 psi of boost is to high..

on a final note the dyno numbers you got are great for N/A which is about 315HP at the wheels..

now with 17 psi of boost you should have no need for NOS... with ballpark numbers with 17psi of boost should yield you about 600 rear wheel HP..

i think i covered everything i wanted to ask and give my opinion on..

Nick

Re: Too much boost

Reply #6 – February 07, 2005, 11:37:58 AM

Block is stock, from 91 stang, block is o-ringed, the heads are 64cc,
I have a d.s.s. maingirdle & windage tray. The main caps are arp studded. On that run i didn't use the nitrous and since i have a 55- bird I haven't had the money lately to put on a new mass air meter
( I want a 80mm pro-m), but I also want new injectors
(probably 55lbs), and as for the nitrous I am probably going to get a spray bar for the front of the intercooler. ( from cryo-2) as the fan i have on the intercooler isn't doing a good enough job.

Re: Too much boost

Reply #7 – February 07, 2005, 12:26:32 PM

Quote from: blownbirds

Block is stock, from 91 stang, block is o-ringed, the heads are 64cc,
I have a d.s.s. maingirdle & windage tray. The main caps are arp studded. On that run i didn't use the nitrous and since i have a 55- bird I haven't had the money lately to put on a new mass air meter
( I want a 80mm pro-m), but I also want new injectors
(probably 55lbs), and as for the nitrous I am probably going to get a spray bar for the front of the intercooler. ( from cryo-2) as the fan i have on the intercooler isn't doing a good enough job.

ok so you answered some of my questions thanks so you are useing a C&L meter.. and the motor should be about 9.0to1 with those heads and the block is oringed.. but!!

the d.s.s. maingirdle is'nt going to help you much.. well as much as most people think.. and i do understand that you have asp studs and does help but it's still a stock block..
it might help you with about 50HP over the stock peak..

i'm allso useing asp main bolts.. they are still not as strong as the arp sutds but not that much weaker.. but alot stronger then stock main bolts..

if you think it will help the motor to handle anymore then that you will be left with a bunch of main caps atached to a maingirdle at the bottom of your oil pan one day..

like i said the stock block will only handle about 600 flywheel HP anything over that is risky.. and one day will go BOOM!!

and all your money will be wasted..

unless your rich!!! and don't care about building a new motor from scratch all the time..

so i'd say since you do have a d.s.s. maingirdle keep the peak flywheel HP under 650 which is about 550@ the wheels..

which would be @ about 10-12psi of boost...

hope i could be of some help

Nick

Re: Too much boost

Reply #8 – February 07, 2005, 01:24:35 PM

I have been running this engine for 4 years on 11lbs without a hiccup with the nitrous.

I just think that the 17lb pulley had a little to much adverse affect on it. The nitrous seemed to help with any sort of detonation problem I've ever had on the 11lb pulley. My car went 11.90 at 132mph on a street tire with the 11lb pulley & 55 shot of the juice

Re: Too much boost

Reply #9 – February 07, 2005, 01:33:42 PM

Quote from: blownbirds

I have been running this engine for 4 years on 11lbs without a hiccup with the nitrous.

I just think that the 17lb pulley had a little to much adverse affect on it. The nitrous seemed to help with any sort of detonation problem I've ever had on the 11lb pulley. My car went 11.90 at 132mph on a street tire with the 11lb pulley & 55 shot of the juice

with 11psi you should be ok with 42lb's but 17 no.. 17 psi is why you blew the head gasket..
a few other questions

what gas where you running and what base timming where you running and do you have any kind of boost retard?
or any kind of ecc tunner? oh and are useing a FMU i would'nt think so with 42's but i figured i'd ask..

Re: Too much boost

Reply #10 – February 07, 2005, 02:48:07 PM

I am running the factory A9L EEC, I do have an FMU, and at the time I was running half 111oct, and half 91oct.

I have the msd 6a box but no boost retard. The timing was at
8 degrees btdc, and I am running two step colder plugs Autolite #23
gapped at 35.
:wtf:

Re: Too much boost

Reply #11 – February 07, 2005, 04:14:34 PM

Quote from: blownbirds

I am running the factory A9L EEC, I do have an FMU, and at the time I was running half 111oct, and half 91oct.

I have the msd 6a box but no boost retard. The timing was at
8 degrees btdc, and I am running two step colder plugs Autolite #23
gapped at 35.
:wtf:

well the fuel mix would give you about 102 octaine mix but thats still not enough..

and i'm not concerned about the stock A9L ECM.

but i now know where you problem/problems lies..

it is 1, the level of boost you ran..

2, your not useing any kind of boost retard.. bigtime NO NO :nono:

3, 8 degrees of is not low enough with that level of boost"17 psi"

it's barely enough with 6psi..

and as for the FMU you can dump as much fuel as you want into the motor. it helps alot but with that much timming it won't matter...

just incase if you did'nt know;) stock ford ECM adds 22degrees of timming @about2500RPM's to the base timming which would give you 30degrees of timming@2500RPM's.. which is great for a N/A motor but dangerious for poweradded motor..

you better get your self some sort of boost retard... and yes i know you said you have bin running this motor for 4 years but you have bin lucky..

their are a few ways to get a boost retard..

1, an MSD boost retard which can be dialed from 0-3degrees per pound of boost..

2, get an ECM that has provisions to program in the right timming to boost level and will allso alow you to reprogram the ECM in other area allso..

or 3, do what Ed "1FSTCAT" did and have the stock ECM flashed and had them program in a timming drop as per the RPM's.. "as the RPM's get higher the more timming is droped" ie lets say @3000 the ECM will drop 2or3 dgrees @4000 2more so on and so on so that by the time you get to 6000RPM's you have enough timming retard for the boost level..
but that allso tricky you don't want to take out to little or to much.. same goes for the MSD boost retard..

i'm useing a MSD 6al and an MSD boost retard and i have the boost retard set at 1.5 degrees of retard per pound of boost which = 9 degrees of retard. my base is set @ 12degrees+the 22 the ECM adds =34 degrees by the time the MSD boost retard see's 6psi it will have taken out 9 degrees which =25 degrees

which wook fine for me but won't be enough for 9+psi..
thats where it gets tricky!!! you see you allso have to try and matain a 22degree plug saturation to get a good cyl fire.. ;)

the other thing is the plugs..

the gap is fine that what i have my plugs gapped at.and the heat range is good too and a smart idea

but!!! i would double check to see if those heads use 20 series plugs ie23/24/25/26.. most aftermarket heads use 39 series plugs ie 3923/3924/3925.. i will allso do some searching for you to.. to make sure your useing the right depth plugs... lol Eddie made the same mistake..

20's use a 1/2"depth 39's use a 3/4 depth

Nick

EDIT...http://www.dartheads.com/faq.aspx#spark

Re: Too much boost

Reply #12 – February 07, 2005, 04:29:46 PM

The plugs are right as that's what world recomended. I am aware of the others because, I set a motor up for my friend, and he has the TFS Twisted Wedge heads.

As for the timing, I lock out the distributor.
( I don't use the spout connector) (also I have an msd coil)

All in all I do agree the 17lbs is excessive on 42lb injectors.

Re: Too much boost

Reply #13 – February 07, 2005, 04:36:47 PM

Quote from: blownbirds

The plugs are right as that's what world recomended. I am aware of the others because, I set a motor up for my friend, and he has the TFS Twisted Wedge heads.

As for the timing, I lock out the distributor.
( I don't use the spout connector) (also I have an msd coil)

All in all I do agree the 17lbs is excessive on 42lb injectors.

lol i think so too.. hell i can't say you don't have boost!!

anyway i would double check on the plugs anyway never mind what world says since you have to take the heads off check for your self i would.. if they do take the 20's the thread depth will be a 1/2 and of corse if they take the 39's it will 3/4

like i said heres the link again dart says they use 3/4
http://www.dartheads.com/faq.aspx#spark but again make sure

Nick

Re: Too much boost

Reply #14 – March 05, 2005, 08:00:23 PM

you guys blow me away

so much has been learned and yet there is so much to learn. :D