23* to 18* setup differences

[swaringim25]

I switched from a 600hp 23* to a 710hp 18* motor and chased setup the rest of the year. We finally found alittle bite with some crazy bar angles but was wondering if there was a few tips for a less radical setup for high hp engines on 4bar with short pull bar setup.

[MasterSbilt_Racer]

I switched from a 600hp 23* to a 710hp 18* motor and chased setup the rest of the year. We finally found alittle bite with some crazy bar angles but was wondering if there was a few tips for a less radical setup for high hp engines on 4bar with short pull bar setup.

If two engines weigh about the same and have similar CG heights, you should make almost no change to the car. Is the 18 degree built by a reputable engine builder? If not, it may have a bad torque curve. Or the driver may need to learn to finesse the pedal a little better instead of just punching it.

[swaringim25]

I drive the car and built both the engines. The 23 is a steel headed motor in a shp block and the 18 is an aluminum headed motor in a little m block so cg weight could come into play. As for finesse, i am not going to deny that i could use more of that because im only a third year driver. Torque curves are very good as both engines were in the car on the chassis dyno.

[JustAddDirt]

what kind of car?
clamp/ spring behind?
biscuit pullbar/ spring?

gearing could play a major roll in handling differences as well.

[swaringim25]

09 shaw spring behind progressive spring 24in pull bar. We tried going from our normal 6.48 to a 6.25 and helped a little but the car just seems like its on top of the track, even when the track is heavy.

[powerslide]

I would say raise the motor a 1/2in-1in, the Lil M block is about 30pds more than the SHP and its low in the car. Not sure how much the steel heads weigh vs the 18 degree heads. But even with them being 18 degree i doubt they weigh as much as a 23degree steel head(probably 10-15lbs lighter per side). Pointing to needing to raise the motor compared to the 23 degree motor yet again. Did the %'s change when you changed motors? I figured if you needed to change gears it would of been the other direction

[swaringim25]

% did not change and we geared it that way hoping to not be in the heart of the torque coming out of the turn. We are also considering retarding the cam.

[JustAddDirt]

well its a typical shaw....lol... good luck

[MasterSbilt_Racer]

I would say raise the motor a 1/2in-1in, the Lil M block is about 30pds more than the SHP and its low in the car. Not sure how much the steel heads weigh vs the 18 degree heads. But even with them being 18 degree i doubt they weigh as much as a 23degree steel head(probably 10-15lbs lighter per side). Pointing to needing to raise the motor compared to the 23 degree motor yet again. Did the %'s change when you changed motors? I figured if you needed to change gears it would of been the other direction

I agree with this 100%.

[HEAVY DUTY]

Restrictor plate

[QQQQ]

If the % was the same, I cant see where raising the motor 1/2 in is going to be the miracle fix to all your problems. There is a big difference in a 23 deg 600 hp motor and a 18 deg 700+ motor, like night and day. Sounds like a right foot problem for sure! Hows that tire wear? Burning them up? Restricting it and giving it a go isnt a bad idea.

[charcoal01]

As I think everyone in Imca land is learning by the regular ass kicking the open motors are getting by the little crate that could, in a modified you really don't need 600 hp. Unless you're on open tires and tacky gumbo clay. Not to be rude or arrogant, but were you finding yourself flat footing the car all the way around the track and still being beat? If so that's the only reason I can see to add 100 more hp to a perfect handling car. You're probably having handling issues because you have more hp and tq than you're tires can possibly hold.

[swaringim25]

as i said before i could use a little more finesse but racing at i55 and tri city if you dont have good hp you might as well go fishing. After racing just 7 times my rookie year in 2011 then winning a track championship in 2012 im not just some joker that cant drive. i have a true setup issue that needs to be identified.

[QQQQ]

as i said before i could use a little more finesse but racing at i55 and tri city if you dont have good hp you might as well go fishing. After racing just 7 times my rookie year in 2011 then winning a track championship in 2012 im not just some joker that cant drive. i have a true setup issue that needs to be identified.Well since your not just some joker, it must be the car. You dont really explain what the car is doing, other than it feels like its on top of the track. Soooo, How much travel are you getting on the pull bar? Have you tried a stiffer spring?

[charcoal01]

Have you weighed both motors? I'm surprised your rear percentage didn't change at all. Have you tried throwing more rear to it? When you say it feels like the car is on top of the track, are you talking about all the way through the corner or just on exit?

[clbaker25x]

Agree too with an earlier post, you went down in gear which means that once you spin the tires they are going to spin like crazy. I am a big believer in going the other way with gear, it does make it a little harder at first to get used to, but it would help you pedal the gas easier because it will shutdown quicker when you let off.

[MM90]

Maybe you found the HP limit of what your chassis/rules can use for traction?

[powerslide]

Have you weighed both motors? I'm surprised your rear percentage didn't change at all. Have you tried throwing more rear to it? When you say it feels like the car is on top of the track, are you talking about all the way through the corner or just on exit?

His block is about 30 pds heavier than the old block(unless he spent 1600 on lightening) then the heads are about 20-30 pds lighter than the old heads. So if he used a crank/rods close to the weight of the other combo i can see how his %'s didnt change. But the mass has been lowered in the car. I would bet he lost RF travel meaning he is "on top" of the track

[MasterSbilt_Racer]

His block is about 30 pds heavier than the old block(unless he spent 1600 on lightening) then the heads are about 20-30 pds lighter than the old heads. So if he used a crank/rods close to the weight of the other combo i can see how his %'s didnt change. But the mass has been lowered in the car. I would bet he lost RF travel meaning he is "on top" of the track

Exactly what I was thinking. There is a big difference in engine, but it seems he is having more trouble than that based on his "on top of the track" comment. I am surprised the engines guys use in mods too when my team has won a lot of super late races with basically his first combo with aluminum heads.

[swaringim25]

Holy cow!!! Some of you guys gave me some really good insight on what I think some of my problems are. I have tried a lot of different things to compensate for a lower cg. And then there's you other guys who just want to grill me for apparently being retarded. I am new so I figured I good get a few different opinions. If I wanted to be told how dumb I was I would have just asked my wife. Now on with more insight. With the setup we are at now I have and will continue to run top five with some very competitive guys. Such as Matt cooper, Lucas lee, and other guys of high caliber. But running with them and running away from them is different. I am not content in spending a ton of money and driving all over the country and running top 5. I want to win!!! So I ask around to get different perspectives. Anyway back to my original problem. I started with a 23* with standard bell housing with block mount starter. Switched to 18* aluminum headed motor with mag bell housing and reverse mount starter. An overall weight change of 3 pounds lighter after the switch. That's why I said no weight % changes on the scale because I didn't want to write all of this if I didn't have too. There simply wasn't hardly any change. I've tried softening rf shock rebound, less preload in pull bar, more lr separation, offsetting pullbar to the left, running more rear% and several other things assuming I just wasn't transferring the weight rearward quick enough and the extra hp was shocking the tires. When I try to finesse the throttle and not spin the tires everyone was flying by me because I had no side bite or drive off. So I move to the top of the track and slam the cushion I usually did decent my won rarely. With the setup I have now I'm pretty much to my limit on bars so I was looking for alternatives. The heightening of the motor sounds like a pretty good place to start. Thank you for those decided to help not bash I sincerely appreciate it.

[MM90]

Easy there buddy, I just re-read through all the post and with the exception of maybe one or two they all had info for you to digest from their own personal experiences. Please do post back to this thread with what you changed and results that followed that change.

[clbaker25x]

How much is your car getting on the RF in the feature? Have you thought about softening your RF spring?

[1Mower]

If you have 100 more hp, why soften pull bar? you should have gone other direction on that. Also, what about cu in of motors? I would be looking at the torgue #'s and possibly a redegree of the cam. What does shaw say to do with sidebite?

[1Mower]

Where did you win Championship? I race at both tracks for referring to...

[swaringim25]

I won championship at sfcr. Went down to 600 on rf. works good on slick but plows the frame on heavy tracks. I put Ina spring rubber in for the heats and worked good at Farmington but still " crazy as it seems" no matter what I do I can't hit my butt with bit hands at pevely or tri city. I haven't go to run there with my bar angles jacked to the sky but I was looking for an answer to not have to run such steep angles. As for softening pullbar, I was trying to slow down torque application.

[swaringim25]

Sorry forgot motor. Both are 4.125 bore 3.75 stroke. 400s. 23 made 609 hp and 515 torque. 18 made 710 hp and 570 torque but it came in a lil earlier. 18 had a Lil sharper torque curve but I only assume it was smooth because its the only 18 I've ever built or ran. Heads are over 300cc with .760 lift I aske around if that seemed radicle but was told that was type sizes and numbers for 18* applications.

[1Mower]

Without knowing all your cars details, I would go back to a standard baseline set up that you know worked with your 600 hp motor and put an additional 1/4 in of preload in pullbar. raise j-bar on frame 1 hole or @ an inch. If you don't have a chain on left rear, make sure your top bar doesn't index passed 46-48 degrees. Remember to only change 1 thing at a time. good luck.

[let-r-eat]

I've seen more than one back up after going to more hp. Part throttle on that 18* with 300CC ports is going to be piss poor and when you try to rpm it where it's running decent you can't plant the power. I saw your high side comment earlier. I bet that thing is junk on the bottom of the racetrack because you have to wait on the thing so much. I'd put a smaller *650* carb on or a slick track carb *something that the secondaries aren't 1:1 and try it. There will likely be no cure for your ailment because putting gear in it increases the multiplication further blowing off the tires. Taking gear out makes you wait longer.