#139: so close to a 10.

[NateCrisman]

Thanks for all the props everyone! Really appriciate it.

Streetcar; totally. I drive it to & from the track and cruise around with it running errands in town. Currently it's a little rough with a few dumb thing to fix up before the car is ready for everyday driver duties: need to fix broken exhaust, get a straight alignment, and I'm considering getting new stock trans and tbelt side engine mounts to rid some vibration. Rear kid seats need to go back in as well. It has current reg/ins/inspection sticker.

I think I have decided to enjoy driving the car all winter (but it gets garaged during snow salt) with springtime sound the rollbar, race seat, harness, major weight loss, and adding my nitrous kit. Think I'm going to try running 10.xxx@130 on stock shortblock. Should take about 75-100 shot on top of current configuration. Nitrous usually adds an unusually large amount of ET compared to MPH, so I think putting a 75shot on the car would take my 11.1@123 and make it a 10.4@130. Not sure how long a stock headgasket with basic ARP's is going to hold that?

Welded diff: I have put one in nearly every dsm iv owned, it doesn't bother me at all. It really sucks if you take out power steering, and makes autox sketchy. But it's cheap, strong, and adds major dragstrip traction. On the street the only difference is a bit of tendancy to oversteer In rain in really tight corners.

WOP: What does QTF mean? (I fail at Internet!) /ubbthreads/images/graemlins/confused.gif

Brian: Dude how can you resist those qtp's calling your name in the garage? Instant 10.5! DO IT! /ubbthreads/images/graemlins/devil.gif

Race Stripes: Ehhhh. I'll pass. One thing I have been neglecting has been the exterior upgrades. Have precut tint sitting hereready to install. Green vinyl to cover the chrome strip. Paint taillights. Swap grill. Straighten the front bumper, clean cuts, new brackets. Want to make the car as clean/smooth looking as possible, but cosmetic work always takes a back seat to spending time on performance and mechanical issues. Someday it will look just right.

Going to make another attempt to nail a 10 on Oct 23. Going to add the 4" cold air intake, boost leak check an try to figure out the boost drop issue. Don't really see being able to hit consistent 10's on driving alone, iv got to pick up some power and I think getting the boost to stay up at higher rpm should be the #1 goal for that.

As for the FMIC: I'm seeing really poor air temps post ic, most of last wednesday's runs I would see gains of 45-50*F from starting line to traps. When I was running the 4" thick garret core on my evo8, the temp gain going down the track was real low, like 15* or something (I posted that data in a previous dragstrip results thread here, gotta go look). Seems the temp gain has gotten worse, which could indicate a boost leak. I still feel there is some big power to be gained in swapping the xspower core for the same size Garret core, as one would hope to expect going from a $200fmic to a $1000fmic. Question is: do I want to spend that money /ubbthreads/images/graemlins/dunno.gif

 

[Andy_S]

QFT = Quoted for Truth

 

[NateCrisman]

Air temp data from 2005 on my evo8:
Quote:

AIT is measured directly after the fmic:

At 31psi with the BR Race FMIC (garret 24"x12"x4" core) , ambient temp is 60*F. Starting line AIT is 71.6*F, top of 3rd temp is 75.2*F, end of 4th gear temp is 86.6*F.
That's a temp gain of 3.6*F in 1-3 gears and 15* in 1-4 gears.

2 Weeks ago at Island Dragway:
At 30psi with the stock evo8 fmic, ambient temp is about 78*F. Starting line AIT is 91.4*F, top of 3rd temp is 131.0*F, end of 4th gear temp is 138.2*F.
That's a temp gain of 39.4*F in 1-3 gears and 46.8*F in 1-4 gears.

This is an incredible change in AIT. The AEM logger was showing about 420whp with the stock fmic at 30psi in 3rd gear. The same math shows 480-490whp at 31psi with the new FMIC, granted there is a 18*F change in ambient temp that helped some. That's a solid 60-70whp gain from the combination of 1psi of boost, 18*F of ambient temp, and the FMIC. The 6+mph gain in trap speed indicates the ems logger is atleast somewhat in reality.




Seems at only 28 to 24psi on a 50trim turbo, the current fmic core on my car (XS Power 24x12x4") My air temps are just about as bad as I was seeing on the Evo8 with stock fmic/GT35R running more boost! Really, if that core was worth even 3mph at this stage, it would put me solidly into the tens.

 

I would do a nice meth kit. $1000 ic cores just aren't necessary when you can put on a meth kit, stay extra cool and not have to reconfigure piping as well.

 

[Barnes]

But wouldn't you say a meth kit would be a band aide fix in that case?

I wonder what kind of pressure drop the PowerXS core causes. If it is as much as it appears in Nate's case, that is a huge lose of HP. Again, it would be worth buying an expensive core if it has much lower pressure drop. Even if an IC lowers temps well, a large pressure drop is just wasted horsepower.

 

^If the IC has a leak in it then that's a different story. Repair the leak or get another similar sized cheap core and run meth. Pressure drop is pretty neglible from every cheaper ebay core I have used and even with a meth kit and new ebay IC you are still way under a grand for a "nice" core. I don't think that's a bandaid at all.

 

[onesickcrx]

Yea I think getting the part you need being a bigger intercooler would be a wise investment. Since no matter what you do the turbo xs one will be holding you back. If you think about it it will help your boost issue probally less of a pressure drop along with the horse power drop because of the IAT.

 

[turbofonz]

ETS 4" core. MUCH cheaper than the BR cores, and they work very well.

 

[NateCrisman]

Brent & I pressure tested the ic to 50psi after he welded the endtank and elbow back in may, so I doubt there is a leak in the core itself. Ifthere is a leak, I bet it's going to be around fuel injectors, tb seals, ic pipe couplings, compressor housing oring, or maybe bov leaking. Or combo of all those.

While a meth kit would help ait, I do see it as a band-aid. I'd rather get the best fmic core that is the ideal, but a meth shot would sure be easier and quicker as I can weld new ic pipes myself nor fab endtanks. On the other hand a nitrous kit does even better, I already own one, and the instal is pretty much exactly the sAme. Frankly, I'd instal the nos kit before buying a meth kit. Maybe I will and just use the smallest 50shot, that would pretty much insure a 10. Hahahah

but none of these solutions fixes the root problem of why boost is dropping off with rpm.

 

[RedTwo]

Hmmm I will let your views on racing stripes slide now that you've told us it is a street car with a factory block!
I don't know any more adjectives to describe it so emoicon (wait, that's not right - I don't cut my self...) will have to do
/ubbthreads/images/graemlins/worthy.gif

 

[NateCrisman]

Well seems I found another issue while the car was up on the lift for the broken axle. Typical /ubbthreads/images/graemlins/mad.gif

the small part of the engine block that has the threaded hole for the front lower trans to block bolt has a crack. Iv had multiple times In the whopping 600miles iv driven the car since building it, had to tighten the 4 trans-block bolts.

First I noticed the top two 14mm bolts loose after the first night at the track and cracked them down. While I had the oil pan off 2 weeks ago, noticed the lower rear 12mm bolt was backed out. At the track last wed, Act250r cought the upper two loose again. Now the lower front is cracked and the 12mm lower is backed out, this time in literally 25miles.

Any ideas on the problem? The engine vibrates real bad with the prothane mounts.

 

[atc250r]

I would start by getting rid of those end mounts and switch over to rubber. Are you going to have a go at having it welded?

 

[Hertz]

Weld it together? /ubbthreads/images/graemlins/devil.gif Locktite?

 

[NateCrisman]

Arg! Big chuck of block is broken off, I think leaking oil. There was about 2/3 quart on the floor under the car. Called Brent @ JMF for his opinion on welding, which he says block casting is shitty metal that gives porous welds. I'd imagine it would be nearly impossible to do a leak-free clean weld with the engine in the car, not to mention the trams has to come off anyway.

Sooo.... Looks like 11.1 will be my season best, as if the engine has to come out, I might as well take my time and do additional fixup at the same time.

 

[turbowop]

The poly mounts don't cause the engine to vibrate anymore than normal, they just allow you to feel it more. Whatever is making those bolts back out will do it with rubber or poly mounts.

 

[atc250r]

I know they don't make it vibrate more but they don't allow the engine to move much at all and that may be "retaining" more vibration in the motor if you know what I mean. I think the broken bolt might be contributing to it somehow. I'm assuming that there's no balance shafts in the motor anymore based on the amount of work Nate put into building the car.

John

 

[turbowop]

There has to be something else doing it though. None of my transmission bolts come loose and I have poly mounts, BS delete and a noisy/rattly twin disk. /ubbthreads/images/graemlins/dunno.gif

 

[atc250r]

Maybe that broken piece of the block is contributing to the problem?

 

[Brianawd]

99% of the time that is caused because the block is missing 1 or both dowels that help locate the trans to the block. When they are not there the trans can move in a twisting motion and losses up the bolts. That will then make the tranny flex away from the block when you are pushing in the clutch. Over time it crack's the block.

 

[NateCrisman]

I'm not sure what's causing the bolts to come loose. Maybe I just haven't ever had all 4 tight at the same time and that little bit of flex from one being loose allows the other 2 to come out? WTF? The front 14mm bolt has never been loose and it was still screwed tight today (into the snapped of chunk of block shown above). Front and rear dowels were in. The correct length bolts were in the right holes. I'v built DSM's from the ground up over and over and done, seriously, 75 DSM tranny swaps & clutch replacements over the years. I'v never seen issues with trans bolts that just refuse to stay tight.

Never had issue with my last racecar w/ poly mounts, no BS shafts, bigger clutch, more vibration.

The thing that is really weird is I tightened up the 12mm lower rear bolt and the top two 14mm bolts when I had the oil pan off 2 weeks ago. The car sat on the lift, drove to my house and the gas station, then to Island last wednesday. Maximum of 25miles total. In that 25 mile span, the rear 12mm was about to fall out, and the top 14mm was real loose at the track after maybe 14miles on the street. Both dowels were there, the correct 6bawd starter plate is there. Clutch engagement is fine. Just don't see how these bolts are coming loose in such little time when all 4 were tight to start this last time.

REALLY sucks that the engine is going to have to come out to fix this, and I may have to get another block if it can't be welded cleanly to stop the oil leak. Won't be getting to the track to run a 10 this year I guess. /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif