Road Race Carbureted Ls1 Dry sump

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ctk30
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Road Race Carbureted Ls1 Dry sump

Post by ctk30 »

Building an engine for my road course late model

Image

It's an ls1 out of a 97 corvette, trying to keep it somewhat budget

So far I have

Probe FPS forged pistons
Scat I beam rods 6.1 bushed
ported 862 heads with pac 1905 springs
Ati Balancer
650 double pumper with choke horn
Moroso 3 stage dry sump
Champ dry sump pan
Clevite H bearings, cam bearings, total seal rings

Need to figure out what lifters I'm going to use, It seems like the morel drop in lifters are pretty decent. Will be shifting before 7000 rpm, probably around 6500-6800. I kind of like the idea of tiebar lifters also

Also thinking about running a dual plane intake, maybe the holley. Will probably run a carb spacer so that the the cowl induction air box stuff is somewhat close to fitting, or I can just modify the air box to raise it. Not sure how the carb sapcer would work with the dual plane, a small one might be helpful since the divider isn't cut down like a lot of manifolds

I need to plug the factory oil pump galley up also for the external dry sump, looks to be two on the pan rail and one in the front

Feel free to make any suggestions, I'm far from an expert

Will be getting a custom ground cam, the class that my car fits in is technically limited to .550 lift and 9.5:1 compression but I'll likely never be on the podium so they'll probably never check, plus with the heads its probably closer to 11:1 so why not go a little bigger with the cam.

This is the cam Mike Jones suggested when I didn't know what heads I was going to run. I'll get all my stuff together and ask him again, don't wanna waste any more of his time.
Cam# LS1, HR73353-74341-110
235/239 @ .050"
.600"/.580" Valve Lift
110 LSA

HR73353
292° @ .06
233° @ .050
151° @ .200
600″

LSHR74341
298°@ .06
239°@ .050
152°@ .200
.580″


Flow sheet for heads

Image

The accessory mounts I've made so far

Image

And dry sump mock up, not sure how I'm going to mount it yet. Have HTD pulleys now

Image

Image
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Re: Road Race Carbureted Ls1 Dry sump

Post by MadBill »

If rules permit, for that RPM range and head flow, I'd say you need a 1,000+ CFM and a good ultra tall single plane manifold. With a close ratio box, the revs shouldn't drop much below 5500 anywhere you can use full throttle and any benefit of a dual plane will be long gone by then. We used a 1,000 CFM Braswell on our 308" SBF road racer and had no problems at all at the bottom end with a production ratio TKO600. My guess: A big carb/single combo would be worth 40 HP average 5-7,000 and 75 HP peak Vs. a 650/dual.

Definitely finalize such details before getting Mike on the case!
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Re: Road Race Carbureted Ls1 Dry sump

Post by af2 »

MadBill wrote:
Definitely finalize such details before getting Mike on the case!
Yes!
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Re: Road Race Carbureted Ls1 Dry sump

Post by ctk30 »

Here's an engine combo from someone that has built many of these cars
My mild road race build by Byron Koury Racing Engines

* freshened ex ASA LS1 short block with Katech rod bolts
* stock 243's with ISKY 165-A valve springs
*Comp rocker trunion upgrade
*Crane 550/550 236/246 106 LSA
* 3 stage Aviaid dry sump system
* Performer RPM intake
* Holley 80541 650 cfm carb


On superflow engine dyno made:

487 HP @ 6400
451 torque @ 3900

400 plus pds ft torque from 3200-6400

We have found previously the EFI version with LS6 intake and stock throttle body usually makes a few less HP, but a bit more torque.

should be an excellent, reliable road race motor for club racing
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Re: Road Race Carbureted Ls1 Dry sump

Post by F1Fever »

Out of curiosity do the 862 heads have the stock size valves
I was no longer driving the car consciously. I was driving it by a kind of instinct, only I was in a different dimension.
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Re: Road Race Carbureted Ls1 Dry sump

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According to the flow sheet they are 2.05/1.55

I should get the heads next week
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Re: Road Race Carbureted Ls1 Dry sump

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I decided not to use the 10an fitting on the pan for the oil inlet because I don't want to trust this pan to seal with 60-70psi of oil flowing through it, the rail isn't the flattest. I'm going to use an adapter on the rear of the block instead

What is your opinions of roller rockers vs stock rockers? I found some roller rockers that will cost about the same as the trunion upgrade. The springs are 394 rate so I figured the stock sliding wouldn't be the best

At this point I think I'm lacking a cam, lifters, an intake, timing chain, msd 6010, and probably some random stuff I forgot

Need to do some research on the timing chain

Image

Keyway cut

Image

Plus on pan rail

Image

Plug in front

Image

Oil pan

Image
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Re: Road Race Carbureted Ls1 Dry sump

Post by pamotorman »

I would go with a katech timing chain setup as they have built more road race LS engines than most other shops.
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Re: Road Race Carbureted Ls1 Dry sump

Post by F1Fever »

Thanks, I could only see the flow #s until I clicked the photo. Nice build btw
I was no longer driving the car consciously. I was driving it by a kind of instinct, only I was in a different dimension.
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Re: Road Race Carbureted Ls1 Dry sump

Post by ctk30 »

Heads arrived, will get some better pictures this weekend. Might have a few questions on what to look for before running them

I think I'll go with the katech chain, I guess a double roller needs clearancing. I need to figure out the timing chain dampener now, the one that fits an ls1 is around 100$ and the ls2 one is 10$

What would be the pros/cons of going to a 1.8 crane lifter? I have some available to me for a really good price
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Re: Road Race Carbureted Ls1 Dry sump

Post by ctk30 »

What would cause these on the exhaust valves only. I was told these were run about 10 1/4 mile passes on a turbo and less than 100 street miles. I don't what they were run on before that.

Valve float?

Do the valves need to be replaced

Image

Image

And this picture which you really can't see anything. There seems to be some variances between valve tip heights, the exhaust is supposed to be higher but on one it seems to be even

Image
Last edited by ctk30 on Thu Dec 17, 2015 12:08 pm, edited 1 time in total.
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Re: Road Race Carbureted Ls1 Dry sump

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Looks like
Yes and Yes
I was no longer driving the car consciously. I was driving it by a kind of instinct, only I was in a different dimension.
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Re: Road Race Carbureted Ls1 Dry sump

Post by pamotorman »

looks like a mixture of new and used valves to me. the ones with the messed up tips can be refaced smooth.
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Re: Road Race Carbureted Ls1 Dry sump

Post by MadBill »

Can't see in the straight edge pic, but if it's only one, maybe a hard tip fell off.
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Re: Road Race Carbureted Ls1 Dry sump

Post by Rick1999 »

MadBill wrote:If rules permit, for that RPM range and head flow, I'd say you need a 1,000+ CFM and a good ultra tall single plane manifold. With a close ratio box, the revs shouldn't drop much below 5500 anywhere you can use full throttle and any benefit of a dual plane will be long gone by then. We used a 1,000 CFM Braswell on our 308" SBF road racer and had no problems at all at the bottom end with a production ratio TKO600. My guess: A big carb/single combo would be worth 40 HP average 5-7,000 and 75 HP peak Vs. a 650/dual.

Definitely finalize such details before getting Mike on the case!
no doubt that would be worth some power but those numbers seem a little optimistic unless the 650 is very, very poorly tuned
Rick Cole
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