Build Thread Want To Blow 5 Years And $50k On A Foxbody? Step By Step Instructions Inside!

Much appreciated Kris! Thanks again for your help. I'll have it ready to go next time and make sure she's running strong so we can turn up the wick. I'm more than happy with the power it makes now. A little more can't hurt though ;)

I was hunting around for some solutions regarding the boost issue. Seems like it can be any of the following:
- wastegate issue/bad diaphragm
- too small wastegate spring
- excessive backpressure
- boost leak
- crappy intercooler

The last suggestion came from a tech at Comp. As soon as I told him I had a cx racing intercooler, he groaned and immediately suspected that to be the problem. They have had low boost issues in the past and it was because of a cheap intercooler. He joked that those are radiators, not intercoolers. It figures that the only part on the entire car that I cheaped out on could be biting me in the ass. I'm going to rule out any other possible issues before I consider a custom intercooler from Bell. The Comp tech said it needs to flow 1500 CFM to keep up with the turbo.

The car is only making 5psi on the 10psi spring. If there is a 5psi (or so) drop across the intercooler, I'll know that is a problem. I can easily refeed my PLX gauge to just read off the compressor and then compare that to what the Holley is reading off the manifold. What I don't get it why it won't budge over 15 psi at all. I figured if it were the intercooler, the boost would still climb as I command more from the boost controller. We had it set as high as 32psi and it still made 15psi. I don't know enough about intercoolers to know if they have a point of 'saturation' where it doesn't matter how much boost is going in because they can only flow a certain amount of CFM out.
 
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Much appreciated Kris! Thanks again for your help. I'll have it ready to go next time and make sure she's running strong so we can turn up the wick. I'm more than happy with the power it makes now. A little more can't hurt though ;)

I was hunting around for some solutions regarding the boost issue. Seems like it can be any of the following:
- wastegate issue/bad diaphragm
- too small wastegate spring
- excessive backpressure
- boost leak
- crappy intercooler

The last suggestion came from a tech at Comp. As soon as I told him I had a cx racing intercooler, he groaned and immediately suspected that to be the problem. They have had low boost issues in the past and it was because of a cheap intercooler. He joked that those are radiators, not intercoolers. It figures that the only part on the entire car that I cheaped out on could be biting me in the ass. I'm going to rule out any other possible issues before I consider a custom intercooler from Bell. The Comp tech said it needs to flow 1500 CFM to keep up with the turbo.

The car is only making 5psi on the 10psi spring. If there is a 5psi (or so) drop across the intercooler, I'll know that is a problem. I can easily refeed my PLX gauge to just read off the compressor and then compare that to what the Holley is reading off the manifold. What I don't get it why it won't budge over 15 psi at all. I figured if it were the intercooler, the boost would still climb as I command more from the boost controller. We had it set as high as 32psi and it still made 15psi. I don't know enough about intercoolers to know if they have a point of 'saturation' where it doesn't matter how much boost is going in because they can only flow a certain amount of CFM out.


If your suspicion is correct, then it's because the intercooler lacks the capacity to flow the volume necessary to fill that outlet tube (and everything down-stream) sufficiently to reach any higher. You have pegged the meter, so to speak.
 
congrats! car is a gorgeous beast! you will have the winter coming to sort out things.......the only good part to the motor issue is i dont have to look around to find a new favorite build to follow for a little while good luck wit her brotha.
 
congrats! car is a gorgeous beast! you will have the winter coming to sort out things.......the only good part to the motor issue is i dont have to look around to find a new favorite build to follow for a little while good luck wit her brotha.
Thanks man. There will be plenty over the winter even without the engine work. Lots left to do in the interior.
 
If your suspicion is correct, then it's because the intercooler lacks the capacity to flow the volume necessary to fill that outlet tube (and everything down-stream) sufficiently to reach any higher. You have pegged the meter, so to speak.
I don't know know a ton about intercooler and backpressure, but I never thought an intercooler could 'saturate' to the point where it just won't allow any more pressure to get to the engine. We were effectively telling the turbo to make 26 psi and then 32 psi on two separate runs, but were still getting 15 psi both times. Horsepower was within 3 hp each pull. I can understand it being a restriction, but it just seems strange that it would be at 15 psi all the time. There must be more of a link to CFM and pressure. I just need to school myself on it a little more.
 
So what's going on with your ride lately Grover? Last I'd heard, you were bringing the power levels down from Super Saiyan 3 to SS1.
Nada, I havent done much of anything to it this year. Put the Cobra rack on it and ran 2 tanks of fuel through it is all.

I have the same Spec stage 3+ clutch and it is very on/off. I still wonder if my tune is also part of the problem but my car is very hard to take off smoothly from a stop and well that makes driving it suck.

I am on the gate spring (15psi) and its still a handful
 
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I don't even have a 3+. I have a 3 with the individual 6 puck design. It's very binary. Kris (the tuner) hated the thing. Lol. They were not friends that day.

I made a call to Clutch Dynamics in Michigan. Spent 20 minutes on the phone with Dan talking about his twin disc that they offer. $540 gets me a very nice organic twin disc setup. That's a lot cheaper than a McLeod RST. Dan seems to really enjoy coming up with tweaks to make his clutches perform better than the big name guys. He has a patent on it as well. I discovered them when I was browsing the forums and people seem to be very happy with them. He is also a phone call away if I have any issues. That beats calling a tech hotline at a large company.
 
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I don't know know a ton about intercooler and backpressure, but I never thought an intercooler could 'saturate' to the point where it just won't allow any more pressure to get to the engine. We were effectively telling the turbo to make 26 psi and then 32 psi on two separate runs, but were still getting 15 psi both times. Horsepower was within 3 hp each pull. I can understand it being a restriction, but it just seems strange that it would be at 15 psi all the time. There must be more of a link to CFM and pressure. I just need to school myself on it a little more.


I think you're still forgetting the volume portion. With a given pump, you have the option of increasing/decreasing pressure and velocity. As pressure increases, volume decreases and vice versa. Where pressure and velocity meet is at the max volume for the pump (your pump volume is variable based on the spool but does have a max).

You jambed all that air into a big and wide tube. I increased in speed a LOT. The speed increased even MORE when you tried confining it to a smaller space but the pressure within the restriction remained the same (whole enclosed circuit is 15 psi). At the exit end of that smaller space (where it opens into a larger restriction), the power used to push that air can not achieve any more speed through that small space. As a result, you're capped at 15 lbs where. There simply isn't enough power to make that volume of air move any faster through that restriction. The easy answer is to give it more room. The power needed to make even more velocity in the same space begins to grow exponentially.
 

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Along those same lines I was concerned about the 2.75" inlet/outlets on the inter-cooler and Greg Banish told me it was fine and would not be a problem

I have 3" to the intercooler then 2.75 into the cooler to 2.75 then directly into a 2.75 to 3" reducer to a 3.5" the 4" at the TB

goofy but what can I say it makes power.
 
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I smell what you're stepping in Noobz. I appreciate the mini dissertation. Definitely makes more sense now. I hope to get some pre and post-intercooler pressures this weekend.


Heh... explanation ended up longer than I'd intended. You probably recall similar discussion back the day when we all started figuring out when OEM fuel rails were too small. :D
 
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Id be willing to bet a ham sandwich that the pressure on the turbo side is higher than 15 psi. You essentially have a nozzle and a diffuser back to back, where a nozzle converts pressure into velocity and the diffuser effectively kills the velocity... Since the air lacks pressure and velocity, it is unable to pressurize V2 to the pressure that it once was.