Skwerl's first hot rod

[skwerl]

Justin said a big part of it is the high compression heads. He said yesterday that my compression must be a lot higher than either of us thought, and he's leery of adding any more timing.

 

[555]

Thats one of the reasons I went for the stage 2 heads and not the stage 3 on new motor.
Still thats impressive numbers and you can easily hit the 9s so go have fun and enjoy.

 

[AutoXRacer]

Justin said a big part of it is the high compression heads. He said yesterday that my compression must be a lot higher than either of us thought, and he's leery of adding any more timing.

Yeah, I sort of calculated the increase of CR with your heads and the other two I bought (stock FRPP and the std CNC-Ported). You are definitely north of the stock 9.8:1...I estimate closer to mid 10s if not higher.

 

[BruceH]

Justin said a big part of it is the high compression heads. He said yesterday that my compression must be a lot higher than either of us thought, and he's leery of adding any more timing.

Do you know the dish cc? IIRC JDM was using -6.5cc but that would result in more than stock compression with the increased stroke and thinner frpp head gaskets. Add in your 48cc combustion chambers and it could get pretty high.

 

[BruceH]

I just came up with 11.12 using the following specs: 48cc chamber, 6.5cc dish, 3.551 bore, 3.8 stroke, .008 deck height, and .031 head gasket. All of the frpp 3v head changing kits I've used have had .031" compressed head gasket thickness.

If we change the dish to 11cc it's 10.42 and at 14cc it would be 10:1. I'm not sure if JDM is using shelf pistons or if they have a custom dish spec.

Edit: A web search comes up with 12.5cc dish. That would make compression 10.21.

 

[Timmbo]

698hp from the 1.9L TVS is very impressive. That's a car in the 9's right there. Congrats.

 

[07TGGT]

Holy shit!

 

[skwerl]

Just got back from the track today and unfortunately those high dyno numbers don't translate into fast time slips on hot days. I lose about 3mph for every 10 degree difference in temperature so the difference between running on a 55-60 degree evening versus an 80+ degree day in full sun is fairly drastic. I was trapping 131-132 today so I'm not even going to bother going back until we have another cool Friday evening (which may or may not happen this season).

I also am not real sure about my new tires. The Mickey Thompson ET Street Pro radials are 28.25" tall versus the 26" tall Hoosiers I was running before. My 60' dropped from 1.53 to 1.68. With the 26" tires I was almost running out of gear at the end of the track so I'm thinking I need to just go with the 27" Hoosiers. My car dead hooks with either tire so that really doesn't make any difference as far as I'm concerned. The 28+ MT is just too tall though.

On the positive side, Justin his wife Rebecca really like the Mickey Thompsons on her car so I think they will go to good use.

 

[555]

Is a different gear out of the question?

 

[skwerl]

It wouldn't help, because then I would just be running out of gear at the top end again. What would help is a shorter 1st gear but that's not happening. I'll just do the best I can with the 27" tire off the line and that should put me at the correct rpm at the finish line.

 

[AutoXRacer]

When are you going back to fine tune the beast!!??

How do you like the new cams?
Any issues with driveability?

 

[skwerl]

The cams are better than the Hot Rods I had before, but we are still having some driveability issues. Justin said the AF is going between 12-16 at part throttle and he cannot control it. He said he was going to research the issue and figure out what's going on with those heads. Full throttle is no problem though.

 

[JimIII@JDM]

The cams are better than the Hot Rods I had before, but we are still having some driveability issues. Justin said the AF is going between 12-16 at part throttle and he cannot control it. He said he was going to research the issue and figure out what's going on with those heads. Full throttle is no problem though.

What fuel injectors are in the car?

 

[skwerl]

Jim, I'm using the 48 or 52 injectors that come from Roush with the TVS2300 stock kit (I bought them from Gerald brand new).

BTW, thank you for the compression ratio information.

 

[JimIII@JDM]

Jim, I'm using the 48 or 52 injectors that come from Roush with the TVS2300 stock kit (I bought them from Gerald brand new).

BTW, thank you for the compression ratio information.

Those Roush injectors can be a little tricky with the transient fueling tables but I'm sure Justin knows what he is doing.

 

[AutoXRacer]

Skwerl, do you have a wide band in the car...?

I can't believe you're making that power with those tiny injectors!!
I'm surprised Justin hasn't sold you on some IDs.

 

[skwerl]

Yes

 

[AutoXRacer]

Yes

What are the AFRs doing when you have the driveability issues?

 

[skwerl]

When it surges at an idle, the rpms and vacuum drop until it stumbles, then it surges back up to 1800rpm before repeating. When it surges AFR swings from 11-12 up to 17 then back. Sometimes it drops low enough to stall and other times it just does it a little and each surge gets progressively smaller until it idles smoothly.

 

[19COBRA93]

It wouldn't help, because then I would just be running out of gear at the top end again. What would help is a shorter 1st gear but that's not happening. I'll just do the best I can with the 27" tire off the line and that should put me at the correct rpm at the finish line.

What RPM are you crossing at? Maybe run a deeper gear and cross at a higher RPM. Your 60' should improve, and you shouldn't lose anything crossing the line just beyond your power band. That's how most of the real drag cars are setup anyway.