Spooling an 8847 turbo

[Stage24u]

Combo in sig.

Stall (manufacturer unknown) is currently 3500-4000 on a TH400 with a 3.90 gear.

Cam is Comp 242/242....can dig out cam card if that helps/needed.

Originally had issues spooling turbo, due to Hooker headers, bought some TA 4 bolt headers, installed them, and spool was greatly increased, but converter is older and may need to be addressed.

Cal tuned the car, before fuel pump ran out, and mentioned the converter felt too "loose".

Spoke with Lane/Dusty at PTC and they recommended a 19 blade 9.5 3200 stall.

Car is built to run 30-35lbs on C16 only, no 91 and alky tune here, and will be 20% street/80% track.

Turbo is older, I am aware, and info from search was very scarce on this turbo.

Any S2 cars run or still run this turbo?

Seen many V8's running this, but not many V6s...is 274ci enough to spool quickly, something of this size?

 

[Mike Licht]

lots of TSO cars used the 4788 turbo. The spool good on a 274 with the right converter, listen to dusty he has the right one there. That big cma will need to be shifted pretty high my 248/248 needed about 7500 RPM to work right but it was fast then 139 MPH at 19 PSI with old cast 70 turbo and p trim
Mike

 

[Stage24u]

Dusty told me shift points would be about 7300-7500.

In regards to 242/242 cam, is it too big for this turbo?

Again, not much info, to digest here, on a 242/242 cam, however info is a plenty on the smaller grinds (206-218).

IS their any major difference between the 4788 and a newer, comparable replacement?

 

[turbobitt]

More info on the cam if you have it
AG


Posted from the TurboBuick.Com mobile app

 

[Mike Licht]

that about right on the shift point, the turbo is fine for some applications bad for others. What is your goal here? What are you doing with car? How fast do you want to go?
Mike

 

[Stage24u]

More info on the cam if you have it
AG

Tonight I will dig out the cam card and post the specs.

Very curious as to everyone's thoughts on this cam, as to whether is to big, right/not right for this application, etc.

that about right on the shift point, the turbo is fine for some applications bad for others. What is your goal here? What are you doing with car? How fast do you want to go?
Mike

Car will be mainly for track use, 1/4 mile, and the occasional grudge race on the street.

Based on the build, roll cage, and suspension work from the previous owner, looks like the car was built to run 8s...should do 9s no problem.

Rear is back halved, tubbed on 15in wide slicks, with a 3.90 gear 9inch and a spool.

The tune is in by Cal, now I'm finishing up the fuel system (Weldon 2025a, race controller, pre/post filters, and dual feeding the rails, etc), then off to the track for times and data logs.

Original tune was llllleeeaaaannnn and meant for a V8, idle was very choppy, and car ran bad. Once he rewrote the tune, car runs/drives/idles perfectly now.

Car is light already- aluminum back seat, bumper supports, fiberglass hood/bumpers/deck lid, manual breaks, manual steering, no ac, no crash bars, etc.

Looking to have street-able low 9s car, that will hook on the street (for the occasional late night grudge race) and hold its own at the track, all without leaning on it too hard.

Kenny told me, when he dyno'd the motor on an engine dyno, it did 1100hp @35psi.......with Cal it out down close to 400whp @8psi, then fuel pump maxed out, so we quit.

Thanks in advance for you guys knowledge, thus far, on this topic. Much appreciated.

 

[Mike Licht]

if it is a race car and you don't mind shifting it at 7500 or so the cam is fine and will make good power as long as the L/S is for a turbo car.
Mike

 

[Mike Licht]

if Kenny D chose the cam It is fine I just noticed he built it.

 

[turbobitt]

Cam sounds like it may be the same as mine spec'd by Kenny about 14 years ago. If you have any details it would be interesting to me to see if its the same. I have some dyno data on that cam.
AG


Posted from the TurboBuick.Com mobile app

 

[Stage24u]

Cam sounds like it may be the same as mine spec'd by Kenny about 14 years ago. If you have any details it would be interesting to me to see if its the same. I have some dyno data on that cam.
AG


Posted from the TurboBuick.Com mobile app

Found the cam card, and looks like I was mistaken on the size....242/242 was actually 224/224

Cam is a hydraulic roller 224/224/.335/.335/115

Cam card says it was for Duttweiller, so is this a custom grind, or an off the shelf grind? Shift points recommended?

Is this a good S2 cam for this turbo?

 

[bison]

Found the cam card, and looks like I was mistaken on the size....242/242 was actually 224/224

Cam is a hydraulic roller 224/224/.335/.335/115

Cam card says it was for Duttweiller, so is this a custom grind, or an off the shelf grind? Shift points recommended?

Is this a good S2 cam for this turbo?

That's a non aggressive 224. There are better options out there especially if trying to match up the the rest of the combo.. Personally it depends on your mph goal. If it's under 160mph trap speeds I'd look into a different turbo. To be able to run more aggressive lobes the springs need to be checked as well as the push rods and all the valvetrain clearances. I could get you into a cam/springs that will work better. Pm me if interested.

 

[turbobitt]

I'm sure it's a custom grind using lobes selected from comps catalog. Those lobes on your cam look to be 3314/3314 intake/exhaust and should be on your cam card. If you ask me it will work ok but can be greatly improved upon using a more aggressive lobe. You can pick up another 10 degrees duration at .200 lift and still retain the 224 at .050 with a different lobe selection and it will pick up more power with probably no noticeable effects on drivability or loss of spool capability. Bison and myself have spent a lot of time mapping many of these lobes and have hard data on the lobe profiles.
AG


Posted from the TurboBuick.Com mobile app

 

[Mike Licht]

The cam is of an older design, yes there is better stuff out there Bison, myself and few other all have experience in this and can give you options. In the end you need to figure out what you really want to do with the car. That cam will still make good power so before you go spending a bunch of money and tearing it apart have a moment to give your self realistic goals about the car. The turbo is likely too big but same thoughts apply

 

[turbobitt]

Based on the OP's goal of low 9's or high 8's, you have the following choices.

1-Run it and see what it will do,leaving everything as is and see what it will do.

2- change cam to better match your current combo and maybe better your goal with the turbo you have.

3- keep the cam and change the turbo to get better response while still maintaining high 8 second potential. Would make it more fun to drive on the street.

Given the information from the OP, it sounds like a mismatch of parts and would do better with a cam change. Just my opinion.
AG




Posted from the TurboBuick.Com mobile app

 

[Stage24u]

I'm sure it's a custom grind using lobes selected from comps catalog. Those lobes on your cam look to be 3314/3314 intake/exhaust and should be on your cam card. If you ask me it will work ok but can be greatly improved upon using a more aggressive lobe. You can pick up another 10 degrees duration at .200 lift and still retain the 224 at .050 with a different lobe selection and it will pick up more power with probably no noticeable effects on drivability or loss of spool capability. Bison and myself have spent a lot of time mapping many of these lobes and have hard data on the lobe profiles.
AG


Posted from the TurboBuick.Com mobile app

Turbobitt- what cam would you recommend and how much power is being left on table with the current cam, in your opinion?

Can you post some of the hard data?

 

[Stage24u]

The cam is of an older design, yes there is better stuff out there Bison, myself and few other all have experience in this and can give you options. In the end you need to figure out what you really want to do with the car. That cam will still make good power so before you go spending a bunch of money and tearing it apart have a moment to give your self realistic goals about the car. The turbo is likely too big but same thoughts apply

Seeking 8s/low 9s what would you change, and what 4 bolt turbo would you run?

I will log some data during runs to see where to current combo stands prior to anything is torn apart.

No point in improving a build, with no baseline to measure the amount of improvement from.

That's a non aggressive 224. There are better options out there especially if trying to match up the the rest of the combo.. Personally it depends on your mph goal. If it's under 160mph trap speeds I'd look into a different turbo. To be able to run more aggressive lobes the springs need to be checked as well as the push rods and all the valvetrain clearances. I could get you into a cam/springs that will work better. Pm me if interested.

Will send you a PM on the cam/spring.

What is this build capable of NOW and what would it be capable of with your improvements?

Car weighs approx 3000 w/driver, 3.90 gear, 32 in tire, engine combo in sig.

 

[turbobitt]

Car is very light. I would run it and see what it would do and establish a baseline.
AG


Posted from the TurboBuick.Com mobile app

 

[turbobitt]

Turbobitt- what cam would you recommend and how much power is being left on table with the current cam, in your opinion?

Can you post some of the hard data?

The cam data is something that bison and I been accumulating and would like to keep the details to ourselves for now. There are a lot of choices when it comes to lobe selection and many of these change when ground on a Buick cam core. We did an extensive study to document this and just would like to speak in very general terms for now. With that being said, your cam is very non aggressive and could be greatly improved upon. So the following is my opinion on your combo,
It sounds like your car is a serious drag car. At 3000# your goal should easily be reached and can also be considered a little conservative considering the existing equipment. Depending on your heads and compression, you may be able to get down to low 8's with some work. The cam specs you published are really low for a 7000 rpm target. At the very least there are better 224 lobe profiles with 10 degrees more duration at .200+ lift. This would be a better cam by far but still may not be the best for your application. Being 80% raced as you stated I would lean more towards optimizing the turbo capabilities and that would mean a definite cam change.
So to answer your question on my idea of a good cam would be a newer 224/224 hyd with solid rollers on a little tighter LSA or something in the 230 to low 240 range with aggressive profile and solid roller. Your heads may need some work to accept the appropriate spring.
The rest of the combo will need to up to par. Fuel pump and injectors of course would need to be adequate for the job.
AG


Posted from the TurboBuick.Com mobile app

 

[Stage24u]

The cam data is something that bison and I been accumulating and would like to keep the details to ourselves for now. There are a lot of choices when it comes to lobe selection and many of these change when ground on a Buick cam core. We did an extensive study to document this and just would like to speak in very general terms for now

Understood.

What exact grind/grinds, accompanied by supporting parts (springs, etc) would you recommend?

This motor was built in July 2007, so the cam is a few years old, and I'm sure much more info has been documented performance-wise on 224/224 grinds in the past 6yrs.

With that being said, your cam is very non aggressive and could be greatly improved upon.

This would be a better cam by far but still may not be the best for your application. Being 80% raced as you stated I would lean more towards optimizing the turbo capabilities and that would mean a definite cam change.

Willing to look at other cam grinds if you want to PM some ideas.

So to answer your question on my idea of a good cam would be a newer 224/224 hyd with solid rollers on a little tighter LSA or something in the 230 to low 240 range with aggressive profile and solid roller.

Difference between solid roller and hydraulic roller? Pros/Cons of each?

Your heads may need some work to accept the appropriate spring.

Current heads are M&A aluminum, fully ported by Duttweiller. Not sure on springs, but I am sure I can call him to find out.

The rest of the combo will need to up to par. Fuel pump and injectors of course would need to be adequate for the job.

In the process of redoing the fuel system, as my Aeromotive A1000 is on its way out.

Adding- Weldon 2025a, pre/post filters, Weldon race controller, -10 line from pump to Y block, 2 -8 split to each rail feed and return, back Y block, -10 return line.

Cal highly recommended a Weldon pump, and I know the fuel system is one are not to skimp on.

Car is very light. I would run it and see what it would do and establish a baseline.

I agree and that is the plan.

 

[norbs]

For what you want to do I would say the turbo is too big. You would be better off with something like a gt42-76, that would put you closer to the air flow capabilities of your current set-up.