Jump to content

Going for 300whp Na


gambler87

Recommended Posts

I poseted this over on 60degreev6 but i thought id repost it here to let u guys chime in on things as well

 

I have bought a 96gtp that had bad heads from the valves being bent by the broken timing belt. I have since gotten another set of heads surfaced and pressure tested. I have ported and gasket matched both sides of the heads.

 

As I was thinking about the job ahead of me of replacing said heads I thought I'd also throw on my ported lower manifold and custom short runner upper plenum with a northstar 75mm throttle body.

 

Then I started researching and all I can find out is that most people go boosted when they want to get power from these motors. So me having a love for these motors but not wanting to be like everyone else, have decided to build a NA one just to see how much a person can get out of one.

 

I have a set of SLR reground cams and will be putting those into a set of 97 cam carriers, and milzy has emailed me back saying that he does still offer 3.4 Dohc headers. So next month when my taxes get back I will be ordering them. I will also be ordering hptuners as then I can tune my Fiero (also 3.4 Dohc) and my Gtp.

I have a FFP UDP, and I have quoted a set of 11 to 1 high compression pistons out from je pistons ( and can get them pretty cheap because I know some of the people who actually make them). I will also be balancing and lightening the whole rotating assembly. I will be running e85 with 42.5lb injectors. I will also be deleting all the evap, egr, and air pump.

 

I'm hoping to get 300whp with this setup. Through a 4t60e trans.

 

 

Sent from my MB886 using Tapatalk

Link to comment
Share on other sites

"No automatic transmission can withstand 7k RPM bitchslaps for very long" :gears:

 

Forgot who said that, but very true and very relevant. Anyway, good luck with the build. High compression Lq1 definitely sounds interesting, just make sure she can REALLY breathe!

Link to comment
Share on other sites

"No automatic transmission can withstand 7k RPM bitchslaps for very long" :gears:

 

Forgot who said that, but very true and very relevant.

 

RobertISaar was the brain behind this if I'm not mistaken.

Link to comment
Share on other sites

You might be right. If OP hits the numbers they're shooting for, it's gonna turn that trans into dust. They were built to handle barely over what most stock engines put out. Even if you went with an HD trans out of a 2nd gen GTP/Regal GS, you'd still be pushing the envelope, especially if you're looking to lay 300 on the GROUND. Truth be told you'd also be losing a ton of power through an auto. I believe someone said something crazy like 40%?? :think:

Link to comment
Share on other sites

Yes I have heard him on 60degree state this. I have ordered a upgraded pump shaft for my 4t65hd. I am going to go with a 2500 stall converter and a 3.69fdr

 

Sent from my MB886 using Tapatalk

Link to comment
Share on other sites

Because the trans I have is always an auto. To swap in a Getrag 282/284 is first off a lot harder than just swap a HD trans in. And u can't find the input shaft seal for a getrag 282 anymore which is part of a almost extinct rebuild kit. Plus the 282 is only rated for around 200ftlbs. The 284 would be an option but I don't have one or any of the other parts to swap one in. I have a getrag 282 in my already LQ1 swapped 87 Fiero. Which the above mentioned motor will be going into after I get the horsepower and quarter mile goal in the Gtp.

 

Sent from my MB886 using Tapatalk

Link to comment
Share on other sites

well if the first trans doesn't last then I will just get another on to build. That's one of the perks of working at a junkyard. That is why I have three spare high flow LQ1 motors laying around to have one rebuilt.

 

Sent from my MB886 using Tapatalk

Link to comment
Share on other sites

INB4: why not just L67 swap it(even though that would clearly violate the N/A portion of the challenge).

 

 

 

but yes, you already know my opinion of the trans situation... i can't see even most of the seriously upgraded 4T6x being too happy with a high powered LQ1 feeding all of that DOHC evil into it. the 4T65 that was hooked up to the LS4 have some unique parts in them to try and prevent total failure...... but they still tend to end up broken and burned out.

 

IF i wanted to get 300 to the wheels with any kind of reliability and with widely available replacements and be stuck with an automatic...... i would be looking at adapting a 4T80, you'll have more drivetrain losses to overcome compared to a 60/65, but those were built to withstand 7000RPM shifts from northstars and do so with pretty damn good reliability. i can't think of the last time i've seen a failed 4T80.

 

if not so available stuff was allowed.... the 6T75 will be a pretty neat option in the years to come.

Link to comment
Share on other sites

my DOHC had 3.73 gears swapped in, transgo shift kit, higher stall converter. the trans still wasn't strong enough for my NA DOHC. Like said it is the RPM that kills these trans the most. also heat...

 

I honestly think the northstar TB is way to big for the DOHC. even on L67 cars the northstar can be too big. going too large can lower the velocity of the incoming air. thus slowing intake velocities and lowering tq and overall flow. also the shape of the northstar tb has very abrupt angles that aren't good for flow.

 

I guess the real question for the build will be around the cams. are they going to be cut for high rpm hp or mid range? after that then figure out if you need to change the length or volume of your short runner intake to accommodate the air flow requirements. Next will be tuning, tuning, more tuning, and once you are sick of it....More tuning.

 

I think your goals for power are more then doable with your listed mods. My DOHC was never dyno'd but it had to be at least 260 hp for me to put down the 14.81 at the track. I had intake, ported maf, tb, upper and lower intake, gasket matched heads, ported front manifold, 2.5" exhaust, FFP ud pulley, L67 injectors, egr/evap/airpump delete, 104 plugs, 3.73 gears, and plenty of tuning.

 

i know you are looking for something different then everyone else, but if power is the final goal, the 3.8 engine is the way to go. when my timing chain died on my DOHC i decided it was time to do the swap. right now i currently am running a top swapped l36 with ported: heads, LIM, blower, TB, Headers, SI valves, light weight push rods and retainers, G8 springs, and a stock pulley. at the track i put down a 13.91 @99.8 because i shift at 6000-6100 i am not in a danger zone on the trans and i have plenty of power and room for improvement as well. with a cam and pulley drops that time will drop considerably.

Link to comment
Share on other sites

I understand ur comment phoenix and I appreciate this whole forums general input on this build.

 

The cams were ground to my and Steve's recommendations for the weight of the car and the flow capacity of the heads that I have.

 

The short runner intake tunes the resonance waves of the intake to around 6,000 rpm and pulls it pretty hard all the way up to 7k.

 

Ben on 60degreev6 has done a lot of flow testing on the n* throttle body on these Dohc motors and he runs on on his grand Prix that he road course races. He has listed that the n* throttle body is a great improvement (yes at a loss of a little low end torque).

 

I have quit with the idea of trying to pull more torque and low end out of this engine because the real capabilities are offered up high. And as anyone knows to make power na its all about rpm and airflow.

 

I am still looking into possibly building a 4t65hd to be able to shift at 7k but that's more money than I have right now.

 

Just a question but what tuner did u use for your 3.4 Dohc?

 

Sent from my MB886 using Tapatalk

Link to comment
Share on other sites

Not too familiar with upgrades to the auto but I think this engine has lots to be gained by just tuning and some exhaust port work. I know Ive seen flow number somewhere.. Im not one to be big on changing fuel so Im biased but I have seen E85 engines apart and there are gummy and the stuff doesn't want to come off just be aware. I think your on the right track as far as the motor goes.

Link to comment
Share on other sites

I honestly think the northstar TB is way to big for the DOHC. even on L67 cars the northstar can be too big. going too large can lower the velocity of the incoming air. thus slowing intake velocities and lowering tq and overall flow. also the shape of the northstar tb has very abrupt angles that aren't good for flow.

 

 

Not to threadjack, but any suggestions on this? I plan on doing the 96/96 intake swap and was thinking of going N* TB on it, but not if there's something better. Or would it be just as good in that case to keep the stock DOHC TB?

Link to comment
Share on other sites

what if you had the stock throttle body bore? smooth flow and youd be maximizing your potential. too big not always good and can potentially make harder to drive. Maxbore seems to be reputable and I used MRZ for mine since he sleeves the 3.1 throttle bodys. Only issue is wait time

Link to comment
Share on other sites

the 3.4 has some to gain from the better/later intakes....

 

but either set of heads already flow...... just ridiculous amounts of air in and out. the biggest issues feel like the cams and compression. for some reason, when GM finalized stuff for the LQ1, they decided on 9.25:1 compression for the 91-95 engines and with relatively tame cam profiles.... you can run on a mixture of piss and ricewater for octane, but no spectacular results like a Q4HO.

Link to comment
Share on other sites

I used a DHP for tuning

 

Also I ported my stock tb. I never out flowed it even at 7150rpm! With a short runner intake and cams you just might out flow it... If you do I recommend an LS1/2 TB as those have a smoother inlet the the North Stars

Link to comment
Share on other sites

I got a ls1 throttle body today and will be making a flange in cadd for it this weekend. Then after it gets done that will be the one I use on my short runner intake.

 

Sent from my MB886 using Tapatalk

Link to comment
Share on other sites

I have found a 4t65hd with 3.29 FDR. I need some info, I'm wanting to switch my 96 motor and trans for my 97 motor with 97 Monte Carlo wiring harness and ecu. And then swap in the 4t65hd. What I'm wondering is what wiring will I need to do? And is there anything else I will need to do to do this swap

 

Sent from my MB886 using Tapatalk

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...