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Chip Birks wrote: ↑Sat Jun 09, 2018 3:38 pm Well, it appears that this under sell/over deliver thing is an industry wide thing. The new CBs measure out at 1.50, giving me .606" at the valve! Gonna have to knock the top off of the guides for clearance, and get rid of my newly installed titanium retainers in order to get the needed spring installed height. Gotta love it.

The more I've thought about it, and consulted with others on the subject, the more I feel like trying yet another direction with this valvetrain. I've contacted my vendor to see if they'd be willing to trade me for a set of 1.3s. Assuming they measure out correctly, it would put me at about .516". I think I'm okay with that. It would allow me to use my ti retainers, and would put way less stress on the valvetrain in general. And like Kalle said, I'll just turn up the boost if i need to.

I wondered about that. I saw on their site they had some 1.3's, and if history repeats it should put you almost where you wanted to be in the first place.

Picked up some SCAT 1.25s, haven't had time to measure them though. The mouse got back burnered for a week or two. Time got away from me, I realized Thursday that I have a big 2 day race weekend next week. I just don't see having the time to get all of the new bits sorted by that point. So out came the big engine. I pulled it apart last night to re-ring, change cylinders and re-seal it. It'll hopefully be headed back into the car in the next couple of days. The compound stuff is getting shelved for a little bit too. I just want to race on something pretty proven and right now the big single works well for what I want. Hopefully back to the mouse in a week or two.

That's weird that they aren't what they advertise.

You measure up those scat rockers yet?

Nah, family is out for the next 4 days though. Probably should spend some time in the oven, I mean garage, while they are gone...

I feel ya! 95 in the shop everyday. Gettin real tired of sweating 12 hours a day!

Well a couple weeks turned into a couple months in a hurry. 5 days after my last post on this thread my wife and i found a house that we love, and just about a month later we moved in. Not a thing has happened to the mouse since then. I attempted to mount it to an engine stand a couple days ago, but didn't have the needed hardware to hold it. I'll get it together through. It's ready to go.

Life happens! That's the fun part of it!

My Scat 1.4's were just over 1.4 and I am running .522" of lift on my 1516cc. It pulls hard from 5-7500 rpm. I just need boost sooner and more of it. So far I have only been able to get 8 lbs and it doesn't start till 4,000. More to play with. Good to see a little work back on yours.

WickedWagens wrote: ↑Tue Oct 09, 2018 12:03 pm My Scat 1.4's were just over 1.4 and I am running .522" of lift on my 1516cc. It pulls hard from 5-7500 rpm. I just need boost sooner and more of it. So far I have only been able to get 8 lbs and it doesn't start till 4,000. More to play with. Good to see a little work back on yours.

You should just be able to swap the turbine for a smaller A/R? This would be a good time to add an exhaust back pressure gauge to see how efficient you are. It could be you just don have enough exhaust gas to push your current turbine and a sub 1:1 ratio.

This was my 2276 with a .48A/R housing. Almost 1:1 boost pressure to exhaust back pressure. I was able to be full boost by about 3500. People told me I should be running a larger A/R for my engine, but a larger size would have just slowed the spool to an RPM not efficient to my setup.

That's interesting. I thought I'd have to buy a giant turbo for my 2276. Glad to see one of the ones I have might work just fine! Also I have never heard of using a back pressure gauge. That's awesome! I always wondered if it was only be feel to know how it was working .

buguy wrote: ↑Tue Oct 09, 2018 5:01 pm That's interesting. I thought I'd have to buy a giant turbo for my 2276. Glad to see one of the ones I have might work just fine! Also I have never heard of using a back pressure gauge. That's awesome! I always wondered if it was only be feel to know how it was working .

Here is my ghetto data logging before I added a input channel to my ECU

[BBvideo=560,315]https://www.youtube.com/watch?v=-tCt4XN2kBM[/BBvideo]

I like your data logger!! Is there an ideal back pressure? Would you ultimately want zero?

WickedWagens wrote: ↑Tue Oct 09, 2018 12:03 pm My Scat 1.4's were just over 1.4 and I am running .522" of lift on my 1516cc. It pulls hard from 5-7500 rpm. I just need boost sooner and more of it. So far I have only been able to get 8 lbs and it doesn't start till 4,000. More to play with. Good to see a little work back on yours.

Do you have a hp goal you are trying to hit???

You can size the turbo for the max hp you want....

The old Subaru RHB5 from the 86-87 GL-10 would probably work well for you.....it's capable of probably 160-180 crank hp and 17 lbs boost. It would have to be in a blow through config though. It would give full boost at less than 3500 rpm on my 1679cc engine.
You would then need an intercooler and probably W/I too to keep the IAT's down.
FI wouldn't hurt either.

An MHI TD04L-13T would be the next step up and support 270 crank hp and 24 plus lbs. boost. It's not for drawthrough either though.

Figure out how much hp you need and then find a turbo that will support that in the middle of it's efficiency map.