Bottom End Recommendations???

D

dumptube

New Member
Joined
Sep 5, 2002
What would you guys recommend for the following?

I want to stay with a 109 block, as I can't afford a stage 1 or 2.
I currently have stock cnc ported heads with larger valves, and a 206/206 flat tappet cam.

My ultimate goal is to have a mid 7 second street car (i.e. pump gas) that I can beat the hell out of, consistently, and not have too many concerns about doing so. Thus, I guess it would be a car that can handle a high 10 in race trim.

What crank? What caps? Rods? Pistons? Girdle? Keep in mind, I'm not made out of money, so if I can stay with any stock stuff, tell me what you think.

TIA
BA
 
Stock pistons will hold up fine, I'd just go witht the 2 center caps if you are on a budget.

If you want to spend some money, go with JE pistons next.
 
The stock turbo crank and rods will be fine for high to mid tens. (Jason has gone 9.90's with the add'n of a girdle) Of course detonation is the killer here. Make sure to have the crank cked before any machine work. Mine was cracked...

The two center mains with studs should be sufficient for your goals, and you avoid the added expense, oil leaks, etc. associated w/a girdle. Use ARP rod bolts. The seat that the rod bolt sits in needs to be chamfered so the ARP bolt seats completely. Piston choice is up to you. As many will tell you here, the stockers are pretty stout. TRW's are an inexpensive alternative that ups the anti in terms of strength.

Finally, I HIGHLY recommend that you seek out a machine shop that has done some of these motors. Not rocket science, but if your average Chevy machine shop is unaware of the tight clearances needed for these motors, disaster is assured.
 
Thanks for the info. I'd rather not girdle the block if I don't have to. Therefore, I could theoretically put on two steel center caps with ARPs, a good crank, and either stock or JE/TRW pistons, and be done with it?

Sounds too easy for 10's.......pretty interesting, if you think about it.

BA
 
Therefore, I could theoretically put on two steel center caps with ARPs, a good crank, and either stock or JE/TRW pistons, and be done with it?
Click to expand...

People have gone easy 10's on less than what you just mentioned. Its all in the tuning and in the quality of the build and machine work. I think when it comes time to rebuild the girdled motor in my street car, I'm gonna go back with stock pistons. The seal w/ them is awesome and they make less noise than aftermarkets.
 
If you have the original turbo crank w/no cracks, you already have a good crank. As John says, people have already gone well into the tens reliably with less. The billet main caps are just added insurance, and if you're like the rest of us, you'll always want to go faster..:D

Also agree w/John about the stock pistons. My Corvette sounds like a Mack truck for the 1st 5 minutes after a cold start. Just have them ck'd for cracks and concentricity as well. You can realize a considerable savings on your rebuild if you retain the stockers. If you don't change crank, rods, or pistons, you won't even need to have the rotating assembly balanced, altho doing so is nice. The factory balance can be off on these motors by a considerable amt. But due to the fact it's a relatively low rpm motor, and you are on a tight budget, it's not absolutely necessary. You realize that you will need to have the block line bored for the main cap installation?

The best place you can spend money on the bottom end of your motor is a fuel system, and data acquisition. What kills these motors is detonation, most often due to insufficient fuel supply. I don't know your setup, but you can't go wrong with a bit of overkill in the fuel pump and injector dept. Make sure to hotwire the fuel pump no matter which one you choose. Turbo Link or Data Scan give real-time data from the sensors, while units like Scan Masters and OTC go thru the ADL and reporting is much slower. They are helpful in tuning, but often if something goes wrong, they can only tell you why your engine blew up. A wideband O2 based system like FAST is the ultimate, but $$$

John, I lived in Plano for many years. (Now in NRH) Do you run your car at Kennedale or Ennis? Member of the Lone Star Performance Buick Club? Look forward to meeting you out there one day.
 
Stock crank and rods. TRW pistons. Main ARP studs, ARP rod bolts and if you have extra $$ 2 center caps.:) Frank
 
Here's the dish.......I've run in the mid 7's in the 1/8th, on many occasions, and still have some tuning to do. I know there's a little more in the combo that I currently have, but feel that I will be close to maxing it out soon. Therefore, as my engine is in need of a rebuild, I figured I'd go ahead and set it up for what I ultimately want to do.

Currently I have:
CNC ported heads with larger valves
206/206 cam
TE-44
THDP
3000 stall converter
Lubrant 110 chip
CAS V2 intercooler
009 injectors
340 pump (hotwired)

I figure I will definitely go up to 50# injectors (for some reason, I really really don't want to go with low impedence, so these will have to be my max injector size). My only question will be how far my single fuel pump can take me?

I do have Turbolink, and an AFPR.

Thanks again,
BA
 
With the 44 and the 50's, I can't see a single 340 getting you too much quicker than some 7.20's. To go quicker, you ought to overcome your reservations toward low-impedence injectors. I'd guess that some 55's with maybe a 62 or 63 turbo and the hotwired 340 would let you see some 7.0's. You can get the ECM modded for ALL injectors for around $120-150 look for them in the Parts for Sale.

Good Luck with it.

John Purdom: Sent you a PM, give me a call sometime.
 
Dumptube-

I emailed you and PM'd you about some parts.

JE's, stock crank, ARP bolts on stock rods, 2 center billet main caps and everything balanced with ported stock iron heads/intake with 70MM TB went 10.40@128mph best in a friend's car with 55's and a TE-63 turbo at 24psi. He had over 150 low 11 and high 10 second passes on his engine. High boost causes the cranks to flex and ultimately after a while the 2 center bearings are toast. Sometimes with high boost 25psi+ the block can crack even with billet center main caps from all the stress.

Good machine work and a shop familiar with these engines is very very important and worth the extra expense.

These cars are ridicously easy to go mid 11's with a stock engine and bolt ons.... and with heads/cam and built bottom end they can handle high to low 10's and high 9's if you are a madman and like pushing the envelope.

-GNX7
 
Originally posted by gnx7
Dumptube-

I emailed you and PM'd you about some parts.

JE's, stock crank, ARP bolts on stock rods, 2 center billet main caps and everything balanced with ported stock iron heads/intake with 70MM TB went 10.40@128mph best in a friend's car with 55's and a TE-63 turbo at 24psi. He had over 150 low 11 and high 10 second passes on his engine. High boost causes the cranks to flex and ultimately after a while the 2 center bearings are toast. Sometimes with high boost 25psi+ the block can crack even with billet center main caps from all the stress.

Good machine work and a shop familiar with these engines is very very important and worth the extra expense.

These cars are ridicously easy to go mid 11's with a stock engine and bolt ons.... and with heads/cam and built bottom end they can handle high to low 10's and high 9's if you are a madman and like pushing the envelope.

-GNX7
Click to expand...

An RX7 w/a GN drivetrain! Gotta love that! I know there's someone on the board w/a 240Z that goes mid 10's. I have a couple of Miatas, and have had some crazy thoughts.... 2275 lbs stock...Hmmm
 
Thanks guys.....hopefully gnx7 will reply, and I'll have the pistons and main caps. I also found a block from Chris McDade. Once I find a good crank, it looks like I am on my way.

Further, I am seriously looking at Cottons CPT66 ball bearing turbo, and I have a 9/11 3200 stall converter on the shelf. I'm not sure why I don't want to go further than 50's, but I really like the fact that I can drive my car wherever I want, and then beat the hell out of it, and run mid 7's to possibly high 6's. However, if I never run a 10, I won't be too disappointed. I just want to make it take the abuse, and have room to spare.

Therefore, would low 7's (consistently) be safe with 50's, 340 hotwired, and a CPT 66 BB turbo not be conceivable?

Thanks again,
BA
 
WHAT SIZE INJECTOR?

Go with Jack's recommendation for his turbo.

A safe DC for injectors is in the 80-85% range, maximum.

HTH :)
 
ummm, no

although you won't need that much boost (23 lbs or so) but adequate fuel will be an issue (ASSumes a stock weight car...36-3700 or so)

if all you do is run 1/8 mile, you will be ok with the 50's and single pump........if you want to go the rest of the way, bigger injectors and a double pump would be better
 
Alright, I have the block, caps, pistons, and crank. Would a good set of lightweight rods be worthwhile, or should I stick with the stockers? If so, which vendors do you go with for the rods?

Thanks,
Brett
 
stock rods have been 9.90's in a few fullweight GN's.

Not worth the dough.... Spend the extra money on ported heads/lower intake......

-GNX7
 
Now, I have a block sent to the machine shop, billet center caps, TRWs, and a new crank........looks like I'll stick with the stock rods.

Thanks for the info.

BA
 
Hey Brett!

Yeah, I left warm Savannah for Anchorage, Alaska. I've lived up here the past 2 years. I'm in the process of buying a TE-45A for my Limited. You haven't swapped turbos out yet? Good luck with the buildup, Ted
 
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